Create Fillable Forms

curl --request POST \
  --url https://api.gonitro.dev/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form method=create-fillable-forms \
  --form 'params={
  "formFields": [
    {
      "pageIndex": 0,
      "fieldType": "TextBox",
      "name": "firstName",
      "boundingBox": [
        72,
        680,
        200,
        18
      ],
      "value": ""
    },
    {
      "pageIndex": 0,
      "fieldType": "CheckBox",
      "name": "agreeToTerms",
      "boundingBox": [
        72,
        620,
        14,
        14
      ],
      "value": ""
    }
  ]
}' \
  --form 'file=<string>'

import requests

url = "https://api.gonitro.dev/generations"

payload = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--"
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "multipart/form-data"
}

response = requests.post(url, data=payload, headers=headers)

print(response.text)

const form = new FormData();
form.append('method', 'create-fillable-forms');
form.append('params', '{
  "formFields": [
    {
      "pageIndex": 0,
      "fieldType": "TextBox",
      "name": "firstName",
      "boundingBox": [
        72,
        680,
        200,
        18
      ],
      "value": ""
    },
    {
      "pageIndex": 0,
      "fieldType": "CheckBox",
      "name": "agreeToTerms",
      "boundingBox": [
        72,
        620,
        14,
        14
      ],
      "value": ""
    }
  ]
}');
form.append('file', '<string>');

const options = {method: 'POST', headers: {Authorization: 'Bearer <token>'}};

options.body = form;

fetch('https://api.gonitro.dev/generations', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.gonitro.dev/generations",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: multipart/form-data"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.gonitro.dev/generations"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.gonitro.dev/generations")
  .header("Authorization", "Bearer <token>")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.gonitro.dev/generations")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "file": {
    "URL": "<string>",
    "contentType": "application/json",
    "metadata": {
      "fileSizeBytes": 123,
      "pageCount": 123
    }
  }
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#400-bad-request",
  "title": "Bad Request",
  "status": 400,
  "detail": "Request validation failed",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#401-unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "Missing or invalid Authorization header",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#404-not-found",
  "title": "Not Found",
  "status": 404,
  "detail": "Resource not found",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#413-content-too-large",
  "title": "Content too large",
  "status": 413,
  "detail": "Uploaded document exceeds the file size limit",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#422-unprocessable-entity",
  "title": "Unprocessable Entity",
  "status": 422,
  "detail": "The request was well-formed but could not be processed",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#500-internal-server-error",
  "title": "Internal Server Error",
  "status": 500,
  "detail": "An unexpected error occurred",
  "instance": "/platform/generations"
}

POST

generations

Create Fillable Forms

curl --request POST \
  --url https://api.gonitro.dev/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form method=create-fillable-forms \
  --form 'params={
  "formFields": [
    {
      "pageIndex": 0,
      "fieldType": "TextBox",
      "name": "firstName",
      "boundingBox": [
        72,
        680,
        200,
        18
      ],
      "value": ""
    },
    {
      "pageIndex": 0,
      "fieldType": "CheckBox",
      "name": "agreeToTerms",
      "boundingBox": [
        72,
        620,
        14,
        14
      ],
      "value": ""
    }
  ]
}' \
  --form 'file=<string>'

import requests

url = "https://api.gonitro.dev/generations"

payload = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--"
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "multipart/form-data"
}

response = requests.post(url, data=payload, headers=headers)

print(response.text)

const form = new FormData();
form.append('method', 'create-fillable-forms');
form.append('params', '{
  "formFields": [
    {
      "pageIndex": 0,
      "fieldType": "TextBox",
      "name": "firstName",
      "boundingBox": [
        72,
        680,
        200,
        18
      ],
      "value": ""
    },
    {
      "pageIndex": 0,
      "fieldType": "CheckBox",
      "name": "agreeToTerms",
      "boundingBox": [
        72,
        620,
        14,
        14
      ],
      "value": ""
    }
  ]
}');
form.append('file', '<string>');

const options = {method: 'POST', headers: {Authorization: 'Bearer <token>'}};

options.body = form;

fetch('https://api.gonitro.dev/generations', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.gonitro.dev/generations",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: multipart/form-data"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.gonitro.dev/generations"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.gonitro.dev/generations")
  .header("Authorization", "Bearer <token>")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.gonitro.dev/generations")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"method\"\r\n\r\ncreate-fillable-forms\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"params\"\r\n\r\n{\r\n  \"formFields\": [\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"TextBox\",\r\n      \"name\": \"firstName\",\r\n      \"boundingBox\": [\r\n        72,\r\n        680,\r\n        200,\r\n        18\r\n      ],\r\n      \"value\": \"\"\r\n    },\r\n    {\r\n      \"pageIndex\": 0,\r\n      \"fieldType\": \"CheckBox\",\r\n      \"name\": \"agreeToTerms\",\r\n      \"boundingBox\": [\r\n        72,\r\n        620,\r\n        14,\r\n        14\r\n      ],\r\n      \"value\": \"\"\r\n    }\r\n  ]\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n<string>\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "file": {
    "URL": "<string>",
    "contentType": "application/json",
    "metadata": {
      "fileSizeBytes": 123,
      "pageCount": 123
    }
  }
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#400-bad-request",
  "title": "Bad Request",
  "status": 400,
  "detail": "Request validation failed",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#401-unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "Missing or invalid Authorization header",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#404-not-found",
  "title": "Not Found",
  "status": 404,
  "detail": "Resource not found",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#413-content-too-large",
  "title": "Content too large",
  "status": 413,
  "detail": "Uploaded document exceeds the file size limit",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#422-unprocessable-entity",
  "title": "Unprocessable Entity",
  "status": 422,
  "detail": "The request was well-formed but could not be processed",
  "instance": "/platform/generations"
}

{
  "type": "https://developers.gonitro.com/docs/build-nitro/errors#500-internal-server-error",
  "title": "Internal Server Error",
  "status": 500,
  "detail": "An unexpected error occurred",
  "instance": "/platform/generations"
}

The Create Fillable Forms method of the Generations endpoint takes a PDF document plus a description of the form fields to create, and writes those fields into the PDF as a real AcroForm, returning a fillable PDF. Pass the source PDF as the file multipart part and the field definitions as a params JSON body. The params payload is exactly the detected-fields output of the Smart Detect Form Fields extraction method — you typically run that method first and pipe its result straight into this one with zero transformation, since both use the same flat formFields shape.

The params body is identical to what Smart Detect Form Fields returns. The usual flow is: call Smart Detect Form Fields to locate the fields, then pass that exact payload here to write them into the PDF.

Parameters

The params object is a flat list of the form fields to create. Each field carries its own pageIndex:

formFields — array of fields to create. Each field has:
- pageIndex — zero-based index of the page the field belongs to.
- fieldType — TextBox or CheckBox.
- name — the field name (becomes the AcroForm field name).
- boundingBox — [x, y, width, height] in PDF points.
- value — optional initial value (defaults to "").

File Upload

Pass the PDF document via the file parameter and the field definitions via params:

curl --request POST \
  --url https://api.gonitro.dev/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Accept: application/pdf' \
  --form method=create-fillable-forms \
  --form 'file=@document.pdf;type=application/pdf' \
  --form 'params={
    "formFields": [
      {
        "pageIndex": 0,
        "fieldType": "TextBox",
        "name": "firstName",
        "boundingBox": [72, 680, 200, 18],
        "value": ""
      },
      {
        "pageIndex": 0,
        "fieldType": "CheckBox",
        "name": "agreeToTerms",
        "boundingBox": [72, 620, 14, 14],
        "value": ""
      }
    ]
  };type=application/json'

The response is a PDF (application/pdf / application/octet-stream) with the supplied fields written as a real AcroForm.

Output File Format

The endpoint can return output either as JSON or as a binary file. The format depends on the Accept header (details below), which defaults to application/json.

Processing

When requesting JSON, you can run the operation synchronously or asynchronously. This is determined by the Prefer header (details below).

In sync mode, the response includes a URL pointing to the processed file.
In async mode, the request creates a Job, and the response contains the Job ID and status so you can track progress.

Binary (octet-stream) responses are only available for synchronous operations.

Custom File Delivery

The endpoint supports custom file-delivery destinations through the optional delivery parameter. You can provide an upload target, such as your own PUT endpoint or a pre-signed S3 URL, and Nitro will upload the resulting file there. This works for both synchronous and asynchronous processing.

Sync delivery
In synchronous calls, the delivery parameter lets you direct Nitro to upload the output file to a custom URL endpoint or a pre-signed URL (e.g S3), by providing an upload url in the uploadResultTo or uploadResultsTo properties.
Custom endpoint

If implementing the upload endpoint by yourself, make sure your code or middleware configuration accepts requests without content-type headers.

S3 delivery
If you are using S3 to manage delivery uploads, follow this AWS documentation to generate a pre-signed PUT URL.
If using the AWS provided Python script, omit the Content-Type in Params to get the pre-signed url. For example:
url = generate_presigned_url( s3_client, "put_object", { "Bucket": args.bucket, "Key": args.key, # Content-Type: "application/octet-stream" => Omit! }, 1000)
Async delivery
In asynchronous flows, you can also provide a custom URL or pre-signed S3 object via uploadResultTo or uploadResultsTo, to upload your file(s) once the Job is done processing.
Callback
For asynchronous processing, you can also include a callback URL within the delivery parameter. This callback is a POST endpoint that Nitro will call once the Job is created and running, providing details about the file-processing job. Example of Nitro’s callback request body:
{ "jobID": "babe2aa7-9b5d-4eb2-a679-5fc12cf0a490", "location": "https://api.gonitro.dev/jobs/babe2aa7-9b5d-4eb2-a679-5fc12cf0a490" }

Response behavior Matrix

This matrix shows the expected response behavior based on content type, sync/async mode, and custom file-delivery settings.

	JSON (`application/json`)	Binary (`application/octet-stream`)
Synchronous	Returns a JSON object with a file(s) URL(s).	Returns the processed file directly as binary.
Asynchronous (`respond-async`)	Returns a JSON object with a Job ID and status.	Async preference ignored, returns sync binary.
Synchronous delivery	File delivered to custom endpoint / Bucket, returns success confirmation.	N/A
Asynchronous delivery	Returns a JSON object with a Job ID and status. The file(s) will be uploaded to the provided PUT endpoint / S3 Bucket at the end of process. If `callback` url is provided, Nitro will notify the endpoint with a JOB ID and location.	N/A

Limits

The Platform API has the following limits:

File size: Maximum of 100 MB per request for direct uploads and synchronous requests; asynchronous requests with remote-file (URL) input allow up to 300 MB. This applies to single-file and multi-file requests (multi-file requests are limited by their combined size). Some operations allow more — Merge accepts up to 1.5 GB for asynchronous remote-file input.
Page count: Maximum of 500 pages per individual document, or 2500 pages for asynchronous requests with remote-file (URL) input. This applies to single-file and multi-file requests. Multiple documents may exceed the page limit in total.
Retention time: Inputs and outputs are deleted approximately 15 minutes after the operation completes.

Request

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

enum<string>

default:*/*

Controls response format and behavior. See endpoint description above for detailed response combinations.

application/json: Returns JSON response with operation result
application/octet-stream: Returns binary file content
*/*: Defaults to JSON response

Available options:

application/json,

application/octet-stream,

*/*

Prefer

enum<string>

Controls synchronous vs asynchronous operation. See endpoint description above for behavior details.

respond-async: Makes request asynchronous, returns job status for polling
No value: Synchronous response

Available options:

respond-async

Body

multipart/form-data

method

enum<string>

default:create-fillable-forms

required

The Generations' endpoint method: create-fillable-forms

Available options:

create-fillable-forms

params

Create Fillable Forms · object

required

A flat list of form fields to write into the PDF, each carrying its own pageIndex. This is the exact detected-fields payload returned by the Smart Detect Form Fields extraction method, which you typically pipe straight into this method with no transformation.

Show child attributes

Example:

{
  "formFields": [
    {
      "pageIndex": 0,
      "fieldType": "TextBox",
      "name": "firstName",
      "boundingBox": [72, 680, 200, 18],
      "value": ""
    },
    {
      "pageIndex": 0,
      "fieldType": "CheckBox",
      "name": "agreeToTerms",
      "boundingBox": [72, 620, 14, 14],
      "value": ""
    }
  ]
}

file

required

The file to process. It can be provided as a binary upload or as a JSON remote file reference.

delivery

object

This endpoint lets you supply your own URL to receive the single-file output. The URL may point to a custom API endpoint or a pre-signed S3 URL.

The HTTP method defaults to PUT, but you can change it based on your implementation needs via the verb parameter. You can also provide custom headers, such as authentication headers or any others required by your endpoint.

Show child attributes

Response

Returns either JSON or binary output depending on the Accept header (defaults to JSON). JSON responses include a file URL for synchronous tasks or a job status for asynchronous tasks. Binary responses return the generated PDF.

Sync - Single File
Async - Job

file

object

Show child attributes

Start Here

PDF Services

Sign API

Reference

Create Fillable Forms

Parameters

File Upload

Output File Format

Processing

Custom File Delivery

Sync delivery

Custom endpoint

S3 delivery

Async delivery

Callback

Response behavior Matrix

Limits

Request

Authorizations

Headers

Body

Response