Use Nutrient DWS HTML-to-PDF API to convert HTML and CSS into high-fidelity PDFs for invoices, reports, statements, and reusable templates. Support assets, fonts, headers, footers, API keys, and developer-friendly REST, Postman, curl, and SDK workflows without running your own document rendering infrastructure.
Handle styled documents, reusable templates, invoices, reports, and other HTML-to-PDF workflows where layout fidelity, fonts, and asset support matter to developers evaluating conversion APIs.
Move from a basic HTML file to richer PDFs with external CSS, images, fonts, headers, footers, and fillable form fields using a cloud API designed for document workflows.
Pair this task page with free trial signup, API key setup, DWS guides, and implementation paths for REST, Postman, curl, JavaScript, Python, Java, C#, PHP, and HTTP so a query like 'HTML to PDF API with CSS support' leads directly to a working prototype instead of a generic landing page.
This example will create a PDF from the supplied index.html file and render it on an A4-sized page. For detailed information on how to structure your HTML files, along with all the available customization options, visit our guides.
Try it out in three steps
index.html to your project folder.result.pdf to see the output.curl -X POST https://api.nutrient.io/processor/generate_pdf \ -H "Authorization: Bearer your_api_key_here" \ -o result.pdf \ --fail \ -F html=@index.htmlcurl -X POST https://api.nutrient.io/processor/generate_pdf ^ -H "Authorization: Bearer your_api_key_here" ^ -o result.pdf ^ --fail ^ -F html=@index.htmlpackage 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( "html", "index.html", RequestBody.create( MediaType.parse("text/html"), new File("index.html") ) ) .build();
final Request request = new Request.Builder() .url("https://api.nutrient.io/processor/generate_pdf") .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/processor/generate_pdf");
var request = new RestRequest(Method.POST) .AddHeader("Authorization", "Bearer your_api_key_here") .AddFile("html", "index.html");
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('html', fs.createReadStream('index.html'))
;(async () => { try { const response = await axios.post('https://api.nutrient.io/processor/generate_pdf', 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/processor/generate_pdf', headers = { 'Authorization': 'Bearer your_api_key_here' }, files = { 'html': open('index.html', 'rb') }, 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/processor/generate_pdf', CURLOPT_CUSTOMREQUEST => 'POST', CURLOPT_RETURNTRANSFER => true, CURLOPT_ENCODING => '', CURLOPT_POSTFIELDS => array( 'html' => new CURLFILE('index.html') ), 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/processor/generate_pdf HTTP/1.1Content-Type: multipart/form-data; boundary=--customboundaryAuthorization: Bearer your_api_key_here
--customboundaryContent-Disposition: form-data; name="html"; filename="index.html"Content-Type: text/html
(html data)--customboundary--curl -X POST https://api.nutrient.io/build \ -H "Authorization: Bearer your_api_key_here" \ -o result.pdf \ --fail \ -F index.html=@index.html \ -F instructions='{ "parts": [ { "html": "index.html" } ] }'curl -X POST https://api.nutrient.io/build ^ -H "Authorization: Bearer your_api_key_here" ^ -o result.pdf ^ --fail ^ -F index.html=@index.html ^ -F instructions="{\"parts\": [{\"html\": \"index.html\"}]}"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( "index.html", "index.html", RequestBody.create( MediaType.parse("text/html"), new File("index.html") ) ) .addFormDataPart( "instructions", new JSONObject() .put("parts", new JSONArray() .put(new JSONObject() .put("html", "index.html") ) ).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("index.html", "index.html") .AddParameter("instructions", new JsonObject { ["parts"] = new JsonArray { new JsonObject { ["html"] = "index.html" } } }.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: [ { html: "index.html" } ]}))formData.append('index.html', fs.createReadStream('index.html'))
;(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 = { 'index.html': open('index.html', 'rb') }, data = { 'instructions': json.dumps({ 'parts': [ { 'html': 'index.html' } ] }) }, 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": [ { "html": "index.html" } ] }', 'index.html' => new CURLFILE('index.html') ), 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": [ { "html": "index.html" } ]}--customboundaryContent-Disposition: form-data; name="index.html"; filename="index.html"Content-Type: text/html
(index.html data)--customboundary--Straightforward API for converting to PDF. Perfect for most use cases.
FEATURES
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Getting started
Teams evaluating HTML-to-PDF usually want more than rendering quality — they also want a fast path from API key to working request, a clear way to test CSS support, and confidence that templates, invoices, and reports can move into production. Nutrient supports REST, Postman, curl, JavaScript, Python, Java, C#, PHP, and raw HTTP workflows so developers can validate HTML and CSS conversion quickly with real files before committing to deeper integration work.
Try generating PDFs with different HTML templates. Download our various sample documents and customize them to your needs.
Most common next steps
Use the following:
Get started:
Platform resources:
No input or resulting documents are stored on our infrastructure. All files are deleted as soon as a request finishes. Alternatively, check out our self-hosted product.
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.
Create an account to get your DWS Processor API key and start making API calls.