Combine multiple PDF files into a single, organized document using a fast, secure, and reliable PDF merge API. Perfect for reports, archives, or batch processing.
Merge PDFs in any order with full control over page sequence. Ideal for assembling invoices, contracts, scanned forms, or multipart reports.
Automatically merge new PDF files in Google Drive using our Zapier integration. Simply drop your PDFs into a folder, and let the Nutrient API handle the rest.
Select a package that suits your needs according to the number of credits you wish to spend. Each API tool and action has a specific credit cost.
This example will merge the two supplied documents into one PDF. The order of the documents in the final PDF is controlled by the order of the parts array.
Try it out in three steps
first-half.pdf and second-half.pdf to your project folder.result.pdf to see the output.curl -X POST https://api.nutrient.io/build \ -H "Authorization: Bearer your_api_key_here" \ -o result.pdf \ --fail \ -F first_half=@first_half.pdf \ -F second_half=@second_half.pdf \ -F instructions='{ "parts": [ { "file": "first_half" }, { "file": "second_half" } ] }'curl -X POST https://api.nutrient.io/build ^ -H "Authorization: Bearer your_api_key_here" ^ -o result.pdf ^ --fail ^ -F first_half=@first_half.pdf ^ -F second_half=@second_half.pdf ^ -F instructions="{\"parts\": [{\"file\": \"first_half\"}, {\"file\": \"second_half\"}]}"package com.example.pspdfkit;
import java.io.File;import java.io.IOException;import java.nio.file.FileSystems;import java.nio.file.Files;import java.nio.file.StandardCopyOption;
import org.json.JSONArray;import org.json.JSONObject;
import okhttp3.MediaType;import okhttp3.MultipartBody;import okhttp3.OkHttpClient;import okhttp3.Request;import okhttp3.RequestBody;import okhttp3.Response;
public final class PspdfkitApiExample { public static void main(final String[] args) throws IOException { final RequestBody body = new MultipartBody.Builder() .setType(MultipartBody.FORM) .addFormDataPart( "first_half", "first_half.pdf", RequestBody.create( MediaType.parse("application/pdf"), new File("first_half.pdf") ) ) .addFormDataPart( "second_half", "second_half.pdf", RequestBody.create( MediaType.parse("application/pdf"), new File("second_half.pdf") ) ) .addFormDataPart( "instructions", new JSONObject() .put("parts", new JSONArray() .put(new JSONObject() .put("file", "first_half") ) .put(new JSONObject() .put("file", "second_half") ) ).toString() ) .build();
final Request request = new Request.Builder() .url("https://api.nutrient.io/build") .method("POST", body) .addHeader("Authorization", "Bearer your_api_key_here") .build();
final OkHttpClient client = new OkHttpClient() .newBuilder() .build();
final Response response = client.newCall(request).execute();
if (response.isSuccessful()) { Files.copy( response.body().byteStream(), FileSystems.getDefault().getPath("result.pdf"), StandardCopyOption.REPLACE_EXISTING ); } else { // Handle the error throw new IOException(response.body().string()); } }}using System;using System.IO;using System.Net;using RestSharp;
namespace PspdfkitApiDemo{ class Program { static void Main(string[] args) { var client = new RestClient("https://api.nutrient.io/build");
var request = new RestRequest(Method.POST) .AddHeader("Authorization", "Bearer your_api_key_here") .AddFile("first_half", "first_half.pdf") .AddFile("second_half", "second_half.pdf") .AddParameter("instructions", new JsonObject { ["parts"] = new JsonArray { new JsonObject { ["file"] = "first_half" }, new JsonObject { ["file"] = "second_half" } } }.ToString());
request.AdvancedResponseWriter = (responseStream, response) => { if (response.StatusCode == HttpStatusCode.OK) { using (responseStream) { using var outputFileWriter = File.OpenWrite("result.pdf"); responseStream.CopyTo(outputFileWriter); } } else { var responseStreamReader = new StreamReader(responseStream); Console.Write(responseStreamReader.ReadToEnd()); } };
client.Execute(request); } }}// This code requires Node.js. Do not run this code directly in a web browser.
const axios = require('axios')const FormData = require('form-data')const fs = require('fs')
const formData = new FormData()formData.append('instructions', JSON.stringify({ parts: [ { file: "first_half" }, { file: "second_half" } ]}))formData.append('first_half', fs.createReadStream('first_half.pdf'))formData.append('second_half', fs.createReadStream('second_half.pdf'))
;(async () => { try { const response = await axios.post('https://api.nutrient.io/build', formData, { headers: formData.getHeaders({ 'Authorization': 'Bearer your_api_key_here' }), responseType: "stream" })
response.data.pipe(fs.createWriteStream("result.pdf")) } catch (e) { const errorString = await streamToString(e.response.data) console.log(errorString) }})()
function streamToString(stream) { const chunks = [] return new Promise((resolve, reject) => { stream.on("data", (chunk) => chunks.push(Buffer.from(chunk))) stream.on("error", (err) => reject(err)) stream.on("end", () => resolve(Buffer.concat(chunks).toString("utf8"))) })}import requestsimport json
response = requests.request( 'POST', 'https://api.nutrient.io/build', headers = { 'Authorization': 'Bearer your_api_key_here' }, files = { 'first_half': open('first_half.pdf', 'rb'), 'second_half': open('second_half.pdf', 'rb') }, data = { 'instructions': json.dumps({ 'parts': [ { 'file': 'first_half' }, { 'file': 'second_half' } ] }) }, stream = True)
if response.ok: with open('result.pdf', 'wb') as fd: for chunk in response.iter_content(chunk_size=8096): fd.write(chunk)else: print(response.text) exit()<?php
$FileHandle = fopen('result.pdf', 'w+');
$curl = curl_init();
curl_setopt_array($curl, array( CURLOPT_URL => 'https://api.nutrient.io/build', CURLOPT_CUSTOMREQUEST => 'POST', CURLOPT_RETURNTRANSFER => true, CURLOPT_ENCODING => '', CURLOPT_POSTFIELDS => array( 'instructions' => '{ "parts": [ { "file": "first_half" }, { "file": "second_half" } ] }', 'first_half' => new CURLFILE('first_half.pdf'), 'second_half' => new CURLFILE('second_half.pdf') ), CURLOPT_HTTPHEADER => array( 'Authorization: Bearer your_api_key_here' ), CURLOPT_FILE => $FileHandle,));
$response = curl_exec($curl);
curl_close($curl);
fclose($FileHandle);POST https://api.nutrient.io/build HTTP/1.1Content-Type: multipart/form-data; boundary=--customboundaryAuthorization: Bearer your_api_key_here
--customboundaryContent-Disposition: form-data; name="instructions"Content-Type: application/json
{ "parts": [ { "file": "first_half" }, { "file": "second_half" } ]}--customboundaryContent-Disposition: form-data; name="first_half"; filename="first_half.pdf"Content-Type: application/pdf
(first_half data)--customboundaryContent-Disposition: form-data; name="second_half"; filename="second_half.pdf"Content-Type: application/pdf
(second_half data)--customboundary--Most common next steps
Use the following:
Get started:
Platform resources:
Nutrient’s infrastructure is SOC 2 Type 2 audited and GDPR-compliant. See our privacy policy and security documentation for details on data handling.
All communication between your application and Nutrient is done via HTTPS to ensure your data is encrypted when it’s sent to us.
All payments are handled by Paddle. Nutrient DWS Processor API never has direct access to any of your payment data.
A PDF merge API combines multiple PDF documents into a single output file over a REST endpoint. Nutrient’s DWS Processor API handles the merge through its build endpoint — each input PDF is added as a parts item, and the output is assembled in the same order.
Each request is authenticated with an HTTP header of the form Authorization: Bearer your_api_key_here using either a live or a test API key. A JSON Web Token (JWT) generated from the API key can be used instead — JWTs can be scoped to specific operations and origins, time-limited, and revoked. See getting started for API key setup.
Yes. The order of the parts array controls the order of documents in the merged PDF, and the same input file can be referenced more than once with different page ranges to reorder or duplicate pages in the output — for example, placing the last page first.
Yes. Live API keys are rate limited to 100 requests per minute per API key across all plan levels. Test API keys are limited to 10 requests per minute, with request and output size capped at 5 MB and watermarked output. See Processor API pricing for details.
Yes. The API is backed by Nutrient’s SOC 2 Type 2-audited infrastructure — built for use in business-critical and regulated workflows.
Yes. Sign up to receive free processing credits and test PDF merging before choosing a plan. See the Processor API pricing page for credit details.
Create an account to get your DWS Processor API key and start making API calls.