Fill PDF Forms

Sample request

cURL

curl --request POST \
  --url 'https://api.pdf.co/v1/pdf/edit/add' \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: YOUR_API_KEY' \
  --data '{
    "async": false,
    "inline": true,
    "name": "f1040-form-filled",
    "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789"
  }'

const response = await fetch(
  "https://api.pdf.co/v1/pdf/edit/add",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-key": "YOUR_API_KEY",
    },
    body: JSON.stringify({
      async: false,
      inline: true,
      name: "f1040-form-filled",
      url: "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
      fieldsString: "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    }),
  }
);
const result = await response.json();
if (!response.ok || result.error) {
  throw new Error(result.message ?? "PDF.co request failed");
}
console.log(result.url);

import requests

response = requests.post(
    "https://api.pdf.co/v1/pdf/edit/add",
    headers={"x-api-key": "YOUR_API_KEY"},
    json={
        "async": False,
        "inline": True,
        "name": "f1040-form-filled",
        "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
        "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    },
)
result = response.json()
if result.get("error"):
    raise RuntimeError(result.get("message", "PDF.co request failed"))
print(result["url"])

using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Text.Json;

var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var payload = JsonSerializer.Serialize(new Dictionary<string, object>
{
    ["async"] = false,
    ["inline"] = true,
    ["name"] = "f1040-form-filled",
    ["url"] = "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    ["fieldsString"] = "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
});

var response = await client.PostAsync(
    "https://api.pdf.co/v1/pdf/edit/add",
    new StringContent(payload, Encoding.UTF8, "application/json")
);
var json = await response.Content.ReadAsStringAsync();
Console.WriteLine(json);

OkHttpClient client = new OkHttpClient();

String jsonPayload = "{\"async\": false, \"inline\": true, \"name\": \"f1040-form-filled\", \"url\": \"https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf\", \"fieldsString\": \"1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789\"}";

Request request = new Request.Builder()
    .url("https://api.pdf.co/v1/pdf/edit/add")
    .addHeader("x-api-key", "YOUR_API_KEY")
    .addHeader("Content-Type", "application/json")
    .post(RequestBody.create(MediaType.parse("application/json"), jsonPayload))
    .build();

try (Response response = client.newCall(request).execute()) {
    System.out.println(response.body().string());
}

<?php
$payload = json_encode([
    "async" => false,
    "inline" => true,
    "name" => "f1040-form-filled",
    "url" => "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString" => "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
]);

$curl = curl_init("https://api.pdf.co/v1/pdf/edit/add");
curl_setopt_array($curl, [
    CURLOPT_HTTPHEADER => [
        "x-api-key: YOUR_API_KEY",
        "Content-Type: application/json",
    ],
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POSTFIELDS => $payload,
]);

echo curl_exec($curl);
curl_close($curl);

{
    "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "url": "https://pdf-temp-files.s3.us-west-2.amazonaws.com/I0C35YE2U9G79PKS443RWZ4ZZSD7CPMS/f1040-form-filled.pdf?X-Amz-Expires=3600&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIA4NRRSZPHPZV7KQXY%2F20260914%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260914T093104Z&X-Amz-SignedHeaders=host&X-Amz-Signature=d2ae6765cf911f8426c757fb484a4bcf0e34827a960588440a86afdd5750a2cd",
    "outputLinkValidTill": "2026-09-14T10:31:04.2051588+00:00",
    "pageCount": 1,
    "error": false,
    "status": 200,
    "name": "f1040-form-filled.pdf",
    "duration": 254,
    "credits": 21,
    "remainingCredits": 88824
}

{
  "error": true,
  "status": 400,
  "message": "Bad request. Typically due to bad input parameters or unreachable input URLs (e.g., access restrictions like login or password)."
}

{
  "error": true,
  "status": 401,
  "message": "Unauthorized. Authentication is required and has failed or has not yet been provided."
}

{
  "error": true,
  "status": 402,
  "message": "Not enough credits."
}

{
  "error": true,
  "status": 403,
  "message": "Access forbidden for input URL."
}

{
  "error": true,
  "status": 404,
  "message": "The requested resource could not be found."
}

{
  "error": true,
  "status": 408,
  "message": "The server timed out waiting for the request."
}

{
  "error": true,
  "status": 429,
  "message": "Too many requests in a given time period."
}

{
  "error": true,
  "status": 441,
  "message": "Invalid Password. Password protected document."
}

{
  "error": true,
  "status": 442,
  "message": "Input document is damaged or of incorrect type."
}

{
  "error": true,
  "status": 443,
  "message": "Permissions. The operation is prohibited by document security settings."
}

{
  "error": true,
  "status": 444,
  "message": "Profiles parsing error. Please ensure that the configuration is supported."
}

{
  "error": true,
  "status": 445,
  "message": "Timeout error. For large documents, use asynchronous mode (async=true) and check status via /job/check."
}

{
  "error": true,
  "status": 446,
  "message": "Some files required for conversion are missing."
}

{
  "error": true,
  "status": 447,
  "message": "Invalid template."
}

{
  "error": true,
  "status": 448,
  "message": "Invalid URL or HTML. Ensure the provided URL is valid and accessible."
}

{
  "error": true,
  "status": 449,
  "message": "Invalid index range. Page index is out of range."
}

{
  "error": true,
  "status": 450,
  "message": "Invalid page range specified."
}

{
  "error": true,
  "status": 452,
  "message": "Invalid URL."
}

{
  "error": true,
  "status": 454,
  "message": "Invalid parameters."
}

{
  "error": true,
  "status": 500,
  "message": "Something went wrong. Please try again or contact support."
}

cURL

curl --request POST \
  --url 'https://api.pdf.co/v1/pdf/edit/add' \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: YOUR_API_KEY' \
  --data '{
    "async": false,
    "inline": true,
    "name": "f1040-form-filled",
    "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789"
  }'

const response = await fetch(
  "https://api.pdf.co/v1/pdf/edit/add",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-key": "YOUR_API_KEY",
    },
    body: JSON.stringify({
      async: false,
      inline: true,
      name: "f1040-form-filled",
      url: "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
      fieldsString: "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    }),
  }
);
const result = await response.json();
if (!response.ok || result.error) {
  throw new Error(result.message ?? "PDF.co request failed");
}
console.log(result.url);

import requests

response = requests.post(
    "https://api.pdf.co/v1/pdf/edit/add",
    headers={"x-api-key": "YOUR_API_KEY"},
    json={
        "async": False,
        "inline": True,
        "name": "f1040-form-filled",
        "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
        "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    },
)
result = response.json()
if result.get("error"):
    raise RuntimeError(result.get("message", "PDF.co request failed"))
print(result["url"])

using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Text.Json;

var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var payload = JsonSerializer.Serialize(new Dictionary<string, object>
{
    ["async"] = false,
    ["inline"] = true,
    ["name"] = "f1040-form-filled",
    ["url"] = "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    ["fieldsString"] = "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
});

var response = await client.PostAsync(
    "https://api.pdf.co/v1/pdf/edit/add",
    new StringContent(payload, Encoding.UTF8, "application/json")
);
var json = await response.Content.ReadAsStringAsync();
Console.WriteLine(json);

OkHttpClient client = new OkHttpClient();

String jsonPayload = "{\"async\": false, \"inline\": true, \"name\": \"f1040-form-filled\", \"url\": \"https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf\", \"fieldsString\": \"1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789\"}";

Request request = new Request.Builder()
    .url("https://api.pdf.co/v1/pdf/edit/add")
    .addHeader("x-api-key", "YOUR_API_KEY")
    .addHeader("Content-Type", "application/json")
    .post(RequestBody.create(MediaType.parse("application/json"), jsonPayload))
    .build();

try (Response response = client.newCall(request).execute()) {
    System.out.println(response.body().string());
}

<?php
$payload = json_encode([
    "async" => false,
    "inline" => true,
    "name" => "f1040-form-filled",
    "url" => "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString" => "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
]);

$curl = curl_init("https://api.pdf.co/v1/pdf/edit/add");
curl_setopt_array($curl, [
    CURLOPT_HTTPHEADER => [
        "x-api-key: YOUR_API_KEY",
        "Content-Type: application/json",
    ],
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POSTFIELDS => $payload,
]);

echo curl_exec($curl);
curl_close($curl);

{
    "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "url": "https://pdf-temp-files.s3.us-west-2.amazonaws.com/I0C35YE2U9G79PKS443RWZ4ZZSD7CPMS/f1040-form-filled.pdf?X-Amz-Expires=3600&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIA4NRRSZPHPZV7KQXY%2F20260914%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260914T093104Z&X-Amz-SignedHeaders=host&X-Amz-Signature=d2ae6765cf911f8426c757fb484a4bcf0e34827a960588440a86afdd5750a2cd",
    "outputLinkValidTill": "2026-09-14T10:31:04.2051588+00:00",
    "pageCount": 1,
    "error": false,
    "status": 200,
    "name": "f1040-form-filled.pdf",
    "duration": 254,
    "credits": 21,
    "remainingCredits": 88824
}

{
  "error": true,
  "status": 400,
  "message": "Bad request. Typically due to bad input parameters or unreachable input URLs (e.g., access restrictions like login or password)."
}

{
  "error": true,
  "status": 401,
  "message": "Unauthorized. Authentication is required and has failed or has not yet been provided."
}

{
  "error": true,
  "status": 402,
  "message": "Not enough credits."
}

{
  "error": true,
  "status": 403,
  "message": "Access forbidden for input URL."
}

{
  "error": true,
  "status": 404,
  "message": "The requested resource could not be found."
}

{
  "error": true,
  "status": 408,
  "message": "The server timed out waiting for the request."
}

{
  "error": true,
  "status": 429,
  "message": "Too many requests in a given time period."
}

{
  "error": true,
  "status": 441,
  "message": "Invalid Password. Password protected document."
}

{
  "error": true,
  "status": 442,
  "message": "Input document is damaged or of incorrect type."
}

{
  "error": true,
  "status": 443,
  "message": "Permissions. The operation is prohibited by document security settings."
}

{
  "error": true,
  "status": 444,
  "message": "Profiles parsing error. Please ensure that the configuration is supported."
}

{
  "error": true,
  "status": 445,
  "message": "Timeout error. For large documents, use asynchronous mode (async=true) and check status via /job/check."
}

{
  "error": true,
  "status": 446,
  "message": "Some files required for conversion are missing."
}

{
  "error": true,
  "status": 447,
  "message": "Invalid template."
}

{
  "error": true,
  "status": 448,
  "message": "Invalid URL or HTML. Ensure the provided URL is valid and accessible."
}

{
  "error": true,
  "status": 449,
  "message": "Invalid index range. Page index is out of range."
}

{
  "error": true,
  "status": 450,
  "message": "Invalid page range specified."
}

{
  "error": true,
  "status": 452,
  "message": "Invalid URL."
}

{
  "error": true,
  "status": 454,
  "message": "Invalid parameters."
}

{
  "error": true,
  "status": 500,
  "message": "Something went wrong. Please try again or contact support."
}

Sample request

cURL

curl --request POST \
  --url 'https://api.pdf.co/v1/pdf/edit/add' \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: YOUR_API_KEY' \
  --data '{
    "async": false,
    "inline": true,
    "name": "f1040-form-filled",
    "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789"
  }'

const response = await fetch(
  "https://api.pdf.co/v1/pdf/edit/add",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-key": "YOUR_API_KEY",
    },
    body: JSON.stringify({
      async: false,
      inline: true,
      name: "f1040-form-filled",
      url: "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
      fieldsString: "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    }),
  }
);
const result = await response.json();
if (!response.ok || result.error) {
  throw new Error(result.message ?? "PDF.co request failed");
}
console.log(result.url);

import requests

response = requests.post(
    "https://api.pdf.co/v1/pdf/edit/add",
    headers={"x-api-key": "YOUR_API_KEY"},
    json={
        "async": False,
        "inline": True,
        "name": "f1040-form-filled",
        "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
        "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    },
)
result = response.json()
if result.get("error"):
    raise RuntimeError(result.get("message", "PDF.co request failed"))
print(result["url"])

using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Text.Json;

var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var payload = JsonSerializer.Serialize(new Dictionary<string, object>
{
    ["async"] = false,
    ["inline"] = true,
    ["name"] = "f1040-form-filled",
    ["url"] = "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    ["fieldsString"] = "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
});

var response = await client.PostAsync(
    "https://api.pdf.co/v1/pdf/edit/add",
    new StringContent(payload, Encoding.UTF8, "application/json")
);
var json = await response.Content.ReadAsStringAsync();
Console.WriteLine(json);

OkHttpClient client = new OkHttpClient();

String jsonPayload = "{\"async\": false, \"inline\": true, \"name\": \"f1040-form-filled\", \"url\": \"https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf\", \"fieldsString\": \"1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789\"}";

Request request = new Request.Builder()
    .url("https://api.pdf.co/v1/pdf/edit/add")
    .addHeader("x-api-key", "YOUR_API_KEY")
    .addHeader("Content-Type", "application/json")
    .post(RequestBody.create(MediaType.parse("application/json"), jsonPayload))
    .build();

try (Response response = client.newCall(request).execute()) {
    System.out.println(response.body().string());
}

<?php
$payload = json_encode([
    "async" => false,
    "inline" => true,
    "name" => "f1040-form-filled",
    "url" => "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString" => "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
]);

$curl = curl_init("https://api.pdf.co/v1/pdf/edit/add");
curl_setopt_array($curl, [
    CURLOPT_HTTPHEADER => [
        "x-api-key: YOUR_API_KEY",
        "Content-Type: application/json",
    ],
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POSTFIELDS => $payload,
]);

echo curl_exec($curl);
curl_close($curl);

{
    "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "url": "https://pdf-temp-files.s3.us-west-2.amazonaws.com/I0C35YE2U9G79PKS443RWZ4ZZSD7CPMS/f1040-form-filled.pdf?X-Amz-Expires=3600&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIA4NRRSZPHPZV7KQXY%2F20260914%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260914T093104Z&X-Amz-SignedHeaders=host&X-Amz-Signature=d2ae6765cf911f8426c757fb484a4bcf0e34827a960588440a86afdd5750a2cd",
    "outputLinkValidTill": "2026-09-14T10:31:04.2051588+00:00",
    "pageCount": 1,
    "error": false,
    "status": 200,
    "name": "f1040-form-filled.pdf",
    "duration": 254,
    "credits": 21,
    "remainingCredits": 88824
}

{
  "error": true,
  "status": 400,
  "message": "Bad request. Typically due to bad input parameters or unreachable input URLs (e.g., access restrictions like login or password)."
}

{
  "error": true,
  "status": 401,
  "message": "Unauthorized. Authentication is required and has failed or has not yet been provided."
}

{
  "error": true,
  "status": 402,
  "message": "Not enough credits."
}

{
  "error": true,
  "status": 403,
  "message": "Access forbidden for input URL."
}

{
  "error": true,
  "status": 404,
  "message": "The requested resource could not be found."
}

{
  "error": true,
  "status": 408,
  "message": "The server timed out waiting for the request."
}

{
  "error": true,
  "status": 429,
  "message": "Too many requests in a given time period."
}

{
  "error": true,
  "status": 441,
  "message": "Invalid Password. Password protected document."
}

{
  "error": true,
  "status": 442,
  "message": "Input document is damaged or of incorrect type."
}

{
  "error": true,
  "status": 443,
  "message": "Permissions. The operation is prohibited by document security settings."
}

{
  "error": true,
  "status": 444,
  "message": "Profiles parsing error. Please ensure that the configuration is supported."
}

{
  "error": true,
  "status": 445,
  "message": "Timeout error. For large documents, use asynchronous mode (async=true) and check status via /job/check."
}

{
  "error": true,
  "status": 446,
  "message": "Some files required for conversion are missing."
}

{
  "error": true,
  "status": 447,
  "message": "Invalid template."
}

{
  "error": true,
  "status": 448,
  "message": "Invalid URL or HTML. Ensure the provided URL is valid and accessible."
}

{
  "error": true,
  "status": 449,
  "message": "Invalid index range. Page index is out of range."
}

{
  "error": true,
  "status": 450,
  "message": "Invalid page range specified."
}

{
  "error": true,
  "status": 452,
  "message": "Invalid URL."
}

{
  "error": true,
  "status": 454,
  "message": "Invalid parameters."
}

{
  "error": true,
  "status": 500,
  "message": "Something went wrong. Please try again or contact support."
}

cURL

curl --request POST \
  --url 'https://api.pdf.co/v1/pdf/edit/add' \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: YOUR_API_KEY' \
  --data '{
    "async": false,
    "inline": true,
    "name": "f1040-form-filled",
    "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789"
  }'

const response = await fetch(
  "https://api.pdf.co/v1/pdf/edit/add",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-key": "YOUR_API_KEY",
    },
    body: JSON.stringify({
      async: false,
      inline: true,
      name: "f1040-form-filled",
      url: "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
      fieldsString: "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    }),
  }
);
const result = await response.json();
if (!response.ok || result.error) {
  throw new Error(result.message ?? "PDF.co request failed");
}
console.log(result.url);

import requests

response = requests.post(
    "https://api.pdf.co/v1/pdf/edit/add",
    headers={"x-api-key": "YOUR_API_KEY"},
    json={
        "async": False,
        "inline": True,
        "name": "f1040-form-filled",
        "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
        "fieldsString": "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
    },
)
result = response.json()
if result.get("error"):
    raise RuntimeError(result.get("message", "PDF.co request failed"))
print(result["url"])

using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Text.Json;

var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var payload = JsonSerializer.Serialize(new Dictionary<string, object>
{
    ["async"] = false,
    ["inline"] = true,
    ["name"] = "f1040-form-filled",
    ["url"] = "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    ["fieldsString"] = "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
});

var response = await client.PostAsync(
    "https://api.pdf.co/v1/pdf/edit/add",
    new StringContent(payload, Encoding.UTF8, "application/json")
);
var json = await response.Content.ReadAsStringAsync();
Console.WriteLine(json);

OkHttpClient client = new OkHttpClient();

String jsonPayload = "{\"async\": false, \"inline\": true, \"name\": \"f1040-form-filled\", \"url\": \"https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf\", \"fieldsString\": \"1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789\"}";

Request request = new Request.Builder()
    .url("https://api.pdf.co/v1/pdf/edit/add")
    .addHeader("x-api-key", "YOUR_API_KEY")
    .addHeader("Content-Type", "application/json")
    .post(RequestBody.create(MediaType.parse("application/json"), jsonPayload))
    .build();

try (Response response = client.newCall(request).execute()) {
    System.out.println(response.body().string());
}

<?php
$payload = json_encode([
    "async" => false,
    "inline" => true,
    "name" => "f1040-form-filled",
    "url" => "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fieldsString" => "1;topmostSubform[0].Page1[0].f1_02[0];John A. Doe|1;topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1];true|1;topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0];123456789",
]);

$curl = curl_init("https://api.pdf.co/v1/pdf/edit/add");
curl_setopt_array($curl, [
    CURLOPT_HTTPHEADER => [
        "x-api-key: YOUR_API_KEY",
        "Content-Type: application/json",
    ],
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POSTFIELDS => $payload,
]);

echo curl_exec($curl);
curl_close($curl);

{
    "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "url": "https://pdf-temp-files.s3.us-west-2.amazonaws.com/I0C35YE2U9G79PKS443RWZ4ZZSD7CPMS/f1040-form-filled.pdf?X-Amz-Expires=3600&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIA4NRRSZPHPZV7KQXY%2F20260914%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20260914T093104Z&X-Amz-SignedHeaders=host&X-Amz-Signature=d2ae6765cf911f8426c757fb484a4bcf0e34827a960588440a86afdd5750a2cd",
    "outputLinkValidTill": "2026-09-14T10:31:04.2051588+00:00",
    "pageCount": 1,
    "error": false,
    "status": 200,
    "name": "f1040-form-filled.pdf",
    "duration": 254,
    "credits": 21,
    "remainingCredits": 88824
}

{
  "error": true,
  "status": 400,
  "message": "Bad request. Typically due to bad input parameters or unreachable input URLs (e.g., access restrictions like login or password)."
}

{
  "error": true,
  "status": 401,
  "message": "Unauthorized. Authentication is required and has failed or has not yet been provided."
}

{
  "error": true,
  "status": 402,
  "message": "Not enough credits."
}

{
  "error": true,
  "status": 403,
  "message": "Access forbidden for input URL."
}

{
  "error": true,
  "status": 404,
  "message": "The requested resource could not be found."
}

{
  "error": true,
  "status": 408,
  "message": "The server timed out waiting for the request."
}

{
  "error": true,
  "status": 429,
  "message": "Too many requests in a given time period."
}

{
  "error": true,
  "status": 441,
  "message": "Invalid Password. Password protected document."
}

{
  "error": true,
  "status": 442,
  "message": "Input document is damaged or of incorrect type."
}

{
  "error": true,
  "status": 443,
  "message": "Permissions. The operation is prohibited by document security settings."
}

{
  "error": true,
  "status": 444,
  "message": "Profiles parsing error. Please ensure that the configuration is supported."
}

{
  "error": true,
  "status": 445,
  "message": "Timeout error. For large documents, use asynchronous mode (async=true) and check status via /job/check."
}

{
  "error": true,
  "status": 446,
  "message": "Some files required for conversion are missing."
}

{
  "error": true,
  "status": 447,
  "message": "Invalid template."
}

{
  "error": true,
  "status": 448,
  "message": "Invalid URL or HTML. Ensure the provided URL is valid and accessible."
}

{
  "error": true,
  "status": 449,
  "message": "Invalid index range. Page index is out of range."
}

{
  "error": true,
  "status": 450,
  "message": "Invalid page range specified."
}

{
  "error": true,
  "status": 452,
  "message": "Invalid URL."
}

{
  "error": true,
  "status": 454,
  "message": "Invalid parameters."
}

{
  "error": true,
  "status": 500,
  "message": "Something went wrong. Please try again or contact support."
}

Try it live: PDF Add → API Tester — send a real request from your browser.

`POST /v1/pdf/edit/add`

You can fill existing form fields in a PDF after identifying the form field names. Once form fields are identified then the fields[] attribute should be used to populate the fields by fieldName .

To see the request size limits, please refer to the Request Size Limits.

Request body

Attributes are case-sensitive and should be inside JSON for POST request. for example: { "url": "https://example.com/file1.pdf" } There are no query parameters.

string

required

URL to the source file url attribute

array[object]

Show field properties

string

required

Name of the form field. To find form fields please use PDF Edit Add Helper.

string

required

Value to set for this field. If you have a checkbox, set X, true, 1, or another text which is different from false to enable the checkbox. For radio buttons and combo boxes, you need to set the item value in text or index of the item to select. To find form fields please use PDF Edit Add Helper.

string

Specify page indices as comma-separated values or ranges to process (e.g. “0, 1, 2-” or “1, 2, 3-7”). The first-page index is 0, Use ”!” before a number for inverted page numbers (e.g. “!0” for the last page). To process all pages, use “0-”. If not specified, the default configuration processes all pages. The input must be in string format.

integer

Override the font size of the text inside the given input field.

string

Name of the font to use to fill out the input field.

boolean

Override font bold style of the text input field.

boolean

Override font italic style of the text input field.

boolean

Override font strikeout style of the text input field.

boolean

Override font underline style of the text input field.

string

Set values for fillable PDF field objects. Each object is made of parameter separated by the ; symbol. See fieldsString for more information.

string

See Profiles for more information.

Show profiles properties

array

Flattening a document renders it as read-only. Handy if you want to remove editing or copying capability.

string

The callback URL (or Webhook) used to receive the POST data. see Webhooks & Callbacks. This is only applicable when async is set to true.

string

HTTP auth user name if required to access source URL.

string

HTTP auth password if required to access source URL.

string

Password for the PDF file.

string

File name for the generated output, the input must be in string format.

integer

default:"60"

Set the expiration time for the output link in minutes. After this specified duration, any generated output file(s) will be automatically deleted from PDF.co Temporary Files Storage. The maximum duration for link expiration varies based on your current subscription plan. To store permanent input files (e.g. re-usable images, pdf templates, documents) consider using PDF.co Built-In Files Storage.

boolean

default:"false"

Set to true to return results inside the response. Otherwise, the endpoint will return a URL to the output file generated.

boolean

default:"false"

Set async to true for long processes to run in the background, API will then return a jobId which you can use with the Background Job Check endpoint. Also see Webhooks & Callbacks

fieldsString

Set values for fillable PDF fields (i.e. fill pdf fields in pdf forms). To fill fields in PDF form, use the following format: page;fieldName;value. Also, the advanced format can be used to override font name, size and style: 0;fieldName;Field Text;12+bold+italic+underline+strikeout;FontName Where: 0;editbox1;text is here;12+bold;Arial To fill the checkbox, use true, for example: 0;checkbox1;true. If you have a checkbox, set X, true, 1, or another text which is different from false to enable the checkbox. For radio buttons and combo boxes, you need to set the item value in text or index of the item to select. To find form fields please use PDF Edit Add Helper. To separate multiple objects, use the | separator. To get the list of all fillable fields in a PDF form, use the /pdf/info/fields endpoint. If you need to include a pipe character within a value, escape it by prefixing with \\ (for example, | should be written as \\| and in a JSON string as \\|).

Flatten Document

Flattening a document renders it as read-only. Handy if you want to remove editing or copying capability.

{
 "profiles": "{ 'FlattenDocument()': [] }"
}

`Example` Payload (Fill PDF Forms)

{
  "async": false,
  "inline": true,
  "name": "f1040-filled",
  "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
  "fields": [
      {
          "fieldName": "topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1]",
          "pages": "1",
          "text": "True"
      },
      {

          "fieldName": "topmostSubform[0].Page1[0].f1_02[0]",
          "pages": "1",
          "text": "John A."
      },
      {

          "fieldName": "topmostSubform[0].Page1[0].f1_03[0]",
          "pages": "1",
          "text": "Doe"
      },
      {
          "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0]",
          "pages": "1",
          "text": "123456789"
      },
      {
          "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]",
          "pages": "1",
          "text": "Joan B.",
          "fontName": "Arial",
          "size": 6,
          "fontBold": true,
          "fontItalic": true,
          "fontStrikeout": true,
          "fontUnderline": true
      },
      {
          "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]",
          "pages": "1",
          "text": "Joan B."
      },
      {
          "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_06[0]",
          "pages": "1",
          "text": "Doe"
      },
      {
          "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_07[0]",
          "pages": "1",
          "text": "987654321"
      }
  ]
}

`Example` Response (Fill PDF Forms)

{
    "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "url": "https://pdf-temp-files.s3.amazonaws.com/cd15a09771554bed88d6419c1e2f2b16/f1040-filled.pdf",
    "pageCount": 3,
    "error": false,
    "status": 200,
    "name": "f1040-filled.pdf",
    "remainingCredits": 99999369,
    "credits": 63
}

Code samples (For Fill PDF Forms)

curl --location --request POST 'https://api.pdf.co/v1/pdf/edit/add' \
--header 'Content-Type: application/json' \
--header 'x-api-key: *******************' \
--data-raw '{
    "async": false,
    "inline": true,
    "name": "f1040-filled",
    "url": "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf",
    "fields": [
        {
            "fieldName": "topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1]",
            "pages": "1",
            "text": "True"
        },
        {

            "fieldName": "topmostSubform[0].Page1[0].f1_02[0]",
            "pages": "1",
            "text": "John A."
        },
        {

            "fieldName": "topmostSubform[0].Page1[0].f1_03[0]",
            "pages": "1",
            "text": "Doe"
        },
        {
            "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0]",
            "pages": "1",
            "text": "123456789"
        },
        {
            "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]",
            "pages": "1",
            "text": "Joan B.",
            "fontName": "Arial",
            "size": 6,
            "fontBold": true,
            "fontItalic": true,
            "fontStrikeout": true,
            "fontUnderline": true
        },
        {
            "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]",
            "pages": "1",
            "text": "Joan B."
        },
        {
            "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_06[0]",
            "pages": "1",
            "text": "Doe"
        },
        {
            "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_07[0]",
            "pages": "1",
            "text": "987654321"
        }
    ],
    "annotations":[
        {
            "text":"Sample Filled with PDF.co API using /pdf/edit/add. Get fields from forms using /pdf/info/fields. This text is be added on the first (0) and the last (!0) pages.",
            "x": 400,
            "y": 10,
            "width": 200,
            "height": 500,
            "size": 12,
            "pages": "0-",
            "color": "FF0000",
            "link": "https://pdf.co"
        }
    ]
  }'

var https = require("https");
var path = require("path");
var fs = require("fs");

// The authentication key (API Key).
// Get your own by registering at https://app.pdf.co
const API_KEY = "***********************************";

// Direct URL of source PDF file.
const SourceFileUrl = "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf";

// PDF document password. Leave empty for unprotected documents.
const Password = "";

// Destination PDF file name
const DestinationFile = "./result.pdf";

// Runs processing asynchronously. Returns Use JobId that you may use with /job/check to check state of the processing (possible states: working, failed, aborted and success). Must be one of: true, false.
const async = false;

// Form field data
var fields = [
    {
        "fieldName": "topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1]",
        "pages": "1",
        "text": "True"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].f1_02[0]",
        "pages": "1",
        "text": "John A."
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].f1_03[0]",
        "pages": "1",
        "text": "Doe"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0]",
        "pages": "1",
        "text": "123456789"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]",
        "pages": "1",
        "text": "Joan B."
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]",
        "pages": "1",
        "text": "Joan B."
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_06[0]",
        "pages": "1",
        "text": "Doe"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_07[0]",
        "pages": "1",
        "text": "987654321"
    }
];

// * Fill forms *
// Prepare request to `PDF Edit` API endpoint
var queryPath = `/v1/pdf/edit/add`;

// JSON payload for api request
var jsonPayload = JSON.stringify({
    name: path.basename(DestinationFile),
    password: Password,
    url: SourceFileUrl,
    async: async,
    fields: fields
});

var reqOptions = {
    host: "api.pdf.co",
    method: "POST",
    path: queryPath,
    headers: {
        "x-api-key": API_KEY,
        "Content-Type": "application/json",
        "Content-Length": Buffer.byteLength(jsonPayload, 'utf8')
    }
};
// Send request
var postRequest = https.request(reqOptions, (response) => {
    response.on("data", (d) => {
        // Parse JSON response
        var data = JSON.parse(d);

        if (data.error == false) {
            // Download the PDF file
            var file = fs.createWriteStream(DestinationFile);
            https.get(data.url, (response2) => {
                response2.pipe(file).on("close", () => {
                    console.log(`Generated PDF file saved to '${DestinationFile}' file.`);
                });
            });
        }
        else {
            // Service reported error
            console.log(data.message);
        }
    });
}).on("error", (e) => {
    // Request error
    console.error(e);
});

// Write request data
postRequest.write(jsonPayload);
postRequest.end();

import os
import requests # pip install requests

# The authentication key (API Key).
# Get your own by registering at https://app.pdf.co
API_KEY = "**************************************"

# Base URL for PDF.co Web API requests
BASE_URL = "https://api.pdf.co/v1"

def main(args = None):
    fillPDFForm()

def fillPDFForm():
    """Fill PDF form using PDF.co Web API"""

    # Prepare requests params as JSON
    # See documentation: https://developer.pdf.co
    payload = "{\n    \"async\": false,\n    \"encrypt\": false,\n    \"name\": \"f1040-filled\",\n    \"url\": \"https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf\",\n    \"fields\": [\n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1]\",\n            \"pages\": \"1\",\n            \"text\": \"True\"\n        },\n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].f1_02[0]\",\n            \"pages\": \"1\",\n            \"text\": \"John A.\"\n        },        \n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].f1_03[0]\",\n            \"pages\": \"1\",\n            \"text\": \"Doe\"\n        },        \n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0]\",\n            \"pages\": \"1\",\n            \"text\": \"123456789\"\n        },\n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]\",\n            \"pages\": \"1\",\n            \"text\": \"Joan B.\"\n        },\n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]\",\n            \"pages\": \"1\",\n            \"text\": \"Joan B.\"\n        },\n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_06[0]\",\n            \"pages\": \"1\",\n            \"text\": \"Doe\"\n        },\n        {\n            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_07[0]\",\n            \"pages\": \"1\",\n            \"text\": \"987654321\"\n        }     \n\n\n\n    ],\n    \"annotations\":[\n        {\n            \"text\":\"Sample Filled with PDF.co API using /pdf/edit/add. Get fields from forms using /pdf/info/fields\",\n            \"x\": 10,\n            \"y\": 10,\n            \"size\": 12,\n            \"pages\": \"0-\",\n            \"color\": \"FFCCCC\",\n            \"link\": \"https://pdf.co\"\n        }\n    ],    \n    \"images\": [        \n    ]\n}"

    # Prepare URL for 'Fill PDF' API request
    url = "{}/pdf/edit/add".format(BASE_URL)

    # Execute request and get response as JSON
    response = requests.post(url, data=payload, headers={"x-api-key": API_KEY, 'Content-Type': 'application/json'})
    if (response.status_code == 200):
        json = response.json()

        if json["error"] == False:
            #  Get URL of result file
            resultFileUrl = json["url"]
            # Download result file
            r = requests.get(resultFileUrl, stream=True)
            if (r.status_code == 200):
                with open(destinationFile, 'wb') as file:
                    for chunk in r:
                        file.write(chunk)
                print(f"Result file saved as \"{destinationFile}\" file.")
            else:
                print(f"Request error: {response.status_code} {response.reason}")
        else:
            # Show service reported error
            print(json["message"])
    else:
        print(f"Request error: {response.status_code} {response.reason}")

if __name__ == '__main__':
    main()

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Net;
using System.Runtime.InteropServices;

namespace PDFcoApiExample
{
    class Program
    {
        // The authentication key (API Key).
        // Get your own by registering at https://app.pdf.co
        const String API_KEY = "*************************";

        // Direct URL of source PDF file.
        const string SourceFileUrl = "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf";
        // PDF document password. Leave empty for unprotected documents.
        const string Password = "";
        // File name for generated output. Must be a String
        const string FileName = "f1040-form-filled";

        // Destination File Name
        const string DestinationFile = "./result.pdf";

        static void Main(string[] args)
        {
            // Create standard .NET web client instance
            WebClient webClient = new WebClient();

            // Set API Key
            webClient.Headers.Add("x-api-key", API_KEY);

            // Values to fill out pdf fields with built-in pdf form filler
            var fields = new List<object> {
                new { fieldName = "topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1]", pages = "1", text = "True" },
                new { fieldName = "topmostSubform[0].Page1[0].f1_02[0]", pages = "1", text = "John A." },
                new { fieldName = "topmostSubform[0].Page1[0].f1_03[0]", pages = "1", text = "Doe" },
                new { fieldName = "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0]", pages = "1", text = "123456789" },
                new { fieldName = "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]", pages = "1", text = "John  B." },
                new { fieldName = "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_06[0]", pages = "1", text = "Doe" },
                new { fieldName = "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_07[0]", pages = "1", text = "987654321" }
            };

            // If enabled, Runs processing asynchronously. Returns Use JobId that you may use with /job/check to check state of the processing (possible states: working,
            var async = false;

            // Prepare requests params as JSON
            // See documentation: https://developer.pdf.co
            Dictionary<string, object> parameters = new Dictionary<string, object>();
            parameters.Add("url", SourceFileUrl);
            parameters.Add("name", FileName);
            parameters.Add("password", Password);
            parameters.Add("async", async);
            parameters.Add("fields", fields);

            // Convert dictionary of params to JSON
            string jsonPayload = JsonConvert.SerializeObject(parameters);

            try
            {
                // URL of "PDF Edit" endpoint
                string url = "https://api.pdf.co/v1/pdf/edit/add";

                // Execute POST request with JSON payload
                string response = webClient.UploadString(url, jsonPayload);

                // Parse JSON response
                JObject json = JObject.Parse(response);

                if (json["error"].ToObject<bool>() == false)
                {
                    // Get URL of generated PDF file
                    string resultFileUrl = json["url"].ToString();

                    // Download generated PDF file
                    webClient.DownloadFile(resultFileUrl, DestinationFile);

                    Console.WriteLine("Generated PDF file saved as \"{0}\" file.", DestinationFile);
                }
                else
                {
                    Console.WriteLine(json["message"].ToString());
                }
            }
            catch (WebException e)
            {
                Console.WriteLine(e.ToString());
            }
            finally
            {
                webClient.Dispose();
            }

            Console.WriteLine();
            Console.WriteLine("Press any key...");
            Console.ReadKey();
        }
    }
}

package com.company;

import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import okhttp3.*;

import java.io.*;
import java.net.*;
import java.nio.file.Path;
import java.nio.file.Paths;

public class Main
{
    // The authentication key (API Key).
    // Get your own by registering at https://app.pdf.co
    final static String API_KEY = "****************************";

    // Direct URL of source PDF file.
    final static String SourceFileUrl = "pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf";
    // PDF document password. Leave empty for unprotected documents.
    final static String Password = "";

    // Destination PDF file name
    final static Path ResultFile = Paths.get(".\\result.pdf");

    public static void main(String[] args) throws IOException
    {
        // Create HTTP client instance
        OkHttpClient webClient = new OkHttpClient();

        // Prepare URL for `PDF Edit` API call
        String query = "https://api.pdf.co/v1/pdf/edit/add";

        // Prepare form filling data
        String fields = "[\n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"True\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].f1_02[0]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"John A.\"\n" +
                "        },        \n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].f1_03[0]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"Doe\"\n" +
                "        },        \n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"123456789\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"Joan B.\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"Joan B.\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_06[0]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"Doe\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"fieldName\": \"topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_07[0]\",\n" +
                "            \"pages\": \"1\",\n" +
                "            \"text\": \"987654321\"\n" +
                "        }     \n" +
                "    ]";

        // Asynchronous Job
        String async = "false";

        // Make correctly escaped (encoded) URL
        URL url = null;
        try
        {
            url = new URI(null, query, null).toURL();
        }
        catch (URISyntaxException e)
        {
            e.printStackTrace();
        }

        // Create JSON payload
        String jsonPayload = String.format("{\n" +
                "    \"url\": \"%s\",\n" +
                "    \"async\": %s,\n" +
                "    \"encrypt\": false,\n" +
                "    \"name\": \"f1040-filled\",\n" +
                "    \"fields\": %s"+
                "}", SourceFileUrl, async, fields);

        // Prepare request body
        RequestBody body = RequestBody.create(MediaType.parse("application/json"), jsonPayload);
        // Prepare request
        Request request = new Request.Builder()
                .url(url)
                .addHeader("x-api-key", API_KEY) // (!) Set API Key
                .addHeader("Content-Type", "application/json")
                .post(body)
                .build();

        // Execute request
        Response response = webClient.newCall(request).execute();

        if (response.code() == 200)
        {
            // Parse JSON response
            JsonObject json = new JsonParser().parse(response.body().string()).getAsJsonObject();

            boolean error = json.get("error").getAsBoolean();
            if (!error)
            {
                // Get URL of generated output file
                String resultFileUrl = json.get("url").getAsString();

                // Download the image file
                downloadFile(webClient, resultFileUrl, ResultFile);

                System.out.printf("Generated file saved to \"%s\" file.", ResultFile.toString());
            }
            else
            {
                // Display service reported error
                System.out.println(json.get("message").getAsString());
            }
        }
        else
        {
            // Display request error
            System.out.println(response.code() + " " + response.message());
        }
    }

    public static void downloadFile(OkHttpClient webClient, String url, Path destinationFile) throws IOException
    {
        // Prepare request
        Request request = new Request.Builder()
                .url(url)
                .build();
        // Execute request
        Response response = webClient.newCall(request).execute();

        byte[] fileBytes = response.body().bytes();

        // Save downloaded bytes to file
        OutputStream output = new FileOutputStream(destinationFile.toFile());
        output.write(fileBytes);
        output.flush();
        output.close();

        response.close();
    }
}

<?php

// The authentication key (API Key).
// Get your own by registering at https://app.pdf.co
$API_KEY = "***********************************";

// Direct URL of source PDF file.
$SourceFileUrl = "https://pdfco-test-files.s3.us-west-2.amazonaws.com/pdf-form/f1040.pdf";


fillPdfForm($API_KEY, $SourceFileUrl);


function fillPdfForm($apiKey, $sourceFileUrl)
{
    // Prepare URL for Fill PDF API call
    $url = "https://api.pdf.co/v1/pdf/edit/add";

    // Field Strings
    $fields = '[{
        "fieldName": "topmostSubform[0].Page1[0].FilingStatus[0].c1_01[1]",
        "pages": "1",
        "text": "True"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].f1_02[0]",
        "pages": "1",
        "text": "John A."
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].f1_03[0]",
        "pages": "1",
        "text": "Doe"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_04[0]",
        "pages": "1",
        "text": "123456789"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_05[0]",
        "pages": "1",
        "text": "Joan B."
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_06[0]",
        "pages": "1",
        "text": "Doe"
    },
    {
        "fieldName": "topmostSubform[0].Page1[0].YourSocial_ReadOrderControl[0].f1_07[0]",
        "pages": "1",
        "text": "987654321"
    }]';// JSON string

    // Convert JSON string to Array
    $fieldsArray = json_decode($fields, true);

    // Prepare requests params
    // See documentation: https://developer.pdf.co
    $parameters = array();

    // Direct URL of source PDF file.
    $parameters["url"] = $sourceFileUrl;

    // Name of resulting file
    $parameters["name"] = "f1040-form-filled";

    // If large input document, process in async mode by passing true
    $parameters["async"] = false;

    $parameters["fields"] = $fieldsArray;

    // Create Json payload
    $data = json_encode($parameters);

    // Create request
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_HTTPHEADER, array("x-api-key: " . $apiKey, "Content-Type: application/json"));
    curl_setopt($curl, CURLOPT_POST, true);
    curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

    // Execute request
    $result = curl_exec($curl);
    $statusCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
    $curlError = curl_error($curl);
    curl_close($curl);

    if ($result === false) {
        // Display CURL error
        echo "fillPdfForm(): " . $curlError . PHP_EOL;
        return;
    }

    if ($statusCode != 200) {
        // Display request error
        echo "fillPdfForm(): request error " . $statusCode . PHP_EOL . $result . PHP_EOL;
        return;
    }

    $json = json_decode($result, true);

    if (!empty($json["error"])) {
        // Display service reported error
        echo "fillPdfForm(): " . $json["message"] . PHP_EOL;
        return;
    }

    // Display URL of the generated PDF file
    echo "Generated PDF file: " . $json["url"] . PHP_EOL;
}

?>

Welcome

Extraction

Editing

PDF Conversion

Excel Conversion

PDF Merging & Splitting

Forms

Find & Search

Document, File & System

Pages

Barcodes

Glossary

Site Index

`POST /v1/pdf/edit/add`

Request body

fieldsString

Flatten Document

`Example` Payload (Fill PDF Forms)

`Example` Response (Fill PDF Forms)

Code samples (For Fill PDF Forms)

​POST /v1/pdf/edit/add

​Request body

​fieldsString

​Flatten Document

​Example Payload (Fill PDF Forms)

​Example Response (Fill PDF Forms)

​Code samples (For Fill PDF Forms)

`POST /v1/pdf/edit/add`

Request body

fieldsString

Flatten Document

`Example` Payload (Fill PDF Forms)

`Example` Response (Fill PDF Forms)

Code samples (For Fill PDF Forms)