Use the PDF-to-HTML API to convert PDF documents to HTML. Nutrient DWS Processor API supports HTML output for workflows such as web publishing, content migration, and document review in browser-based systems.
The /build endpoint handles PDF-to-HTML conversion. Add the source PDF as a parts item, and set output.type to html.
For signup, pricing, and task-level examples, refer to the PDF-to-HTML API task page.
Convert a PDF to HTML
The following example converts document.pdf to result.html:
curl -X POST https://api.nutrient.io/build \ -H "Authorization: Bearer your_api_key_here" \ -o result.html \ --fail \ -F file=@document.pdf \ -F instructions='{ "parts": [ { "file": "file" } ], "output": { "type": "html" } }'curl -X POST https://api.nutrient.io/build ^ -H "Authorization: Bearer your_api_key_here" ^ -o result.html ^ --fail ^ -F file=@document.pdf ^ -F instructions="{\"parts\": [{\"file\": \"file\"}], \"output\": {\"type\": \"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( "file", "document.pdf", RequestBody.create( MediaType.parse("application/pdf"), new File("document.pdf") ) ) .addFormDataPart( "instructions", new JSONObject() .put("parts", new JSONArray() .put(new JSONObject() .put("file", "file") ) ) .put("output", new JSONObject() .put("type", "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.html"), 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("file", "document.pdf") .AddParameter("instructions", new JsonObject { ["parts"] = new JsonArray { new JsonObject { ["file"] = "file" } }, ["output"] = new JsonObject { ["type"] = "html" } }.ToString());
request.AdvancedResponseWriter = (responseStream, response) => { if (response.StatusCode == HttpStatusCode.OK) { using (responseStream) { using var outputFileWriter = File.OpenWrite("result.html"); 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: "file" } ], output: { type: "html" }}))formData.append('file', fs.createReadStream('document.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.html")) } 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 = { 'file': open('document.pdf', 'rb') }, data = { 'instructions': json.dumps({ 'parts': [ { 'file': 'file' } ], 'output': { 'type': 'html' } }) }, stream = True)
if response.ok: with open('result.html', 'wb') as fd: for chunk in response.iter_content(chunk_size=8096): fd.write(chunk)else: print(response.text) exit()<?php
$FileHandle = fopen('result.html', '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": "file" } ], "output": { "type": "html" } }', 'file' => new CURLFILE('document.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": "file" } ], "output": { "type": "html" }}--customboundaryContent-Disposition: form-data; name="file"; filename="document.pdf"Content-Type: application/pdf
(file data)--customboundary--Use page layout or reflow layout
HTML output supports two layout modes:
page— Preserves the original page structure and segments content by page.reflow— Converts the document to a continuous flow of content without page breaks.
Use page layout when you need to preserve the original page structure. Use reflow layout when the HTML should behave more like a web article or continuous document.
Use this instructions object to set the layout to reflow:
{ "parts": [ { "file": "document" } ], "output": { "type": "html", "layout": "reflow" }}Convert a PDF from a URL
For remotely hosted source files, send a JSON request and pass the source URL in parts[].file.url. Use this instructions object:
{ "parts": [ { "file": { "url": "https://example.com/document.pdf" } } ], "output": { "type": "html", "layout": "page" }}Shell
Run this request to convert a PDF from a URL:
curl -X POST https://api.nutrient.io/build \ -H "Authorization: Bearer $NUTRIENT_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "parts": [ { "file": { "url": "https://example.com/document.pdf" } } ], "output": { "type": "html", "layout": "page" } }' \ -o result.htmlConvert selected PDF pages
Use parts[].pages to convert only a page range from the source PDF. Page indexes are zero-based, and negative values count from the end of the document.
The following example converts the first three pages to HTML:
{ "parts": [ { "file": "document", "pages": { "start": 0, "end": 2 } } ], "output": { "type": "html", "layout": "page" }}The end value is inclusive, so { "start": 0, "end": 2 } includes pages zero, one, and two.
Convert password-protected PDFs
If the source PDF is password-protected, include the password on the part. Use this instructions object:
{ "parts": [ { "file": "protected_document", "password": "document-password" } ], "output": { "type": "html", "layout": "reflow" }}Nutrient DWS Processor API uses the password only to open the source document for processing.
Choose a layout
Choose the HTML layout based on how you’ll use the output.
| Layout | Use when |
|---|---|
page | You want to preserve the original document’s page boundaries and page-oriented structure. |
reflow | You want continuous HTML for content migration, web publishing, indexing, or responsive display. |
PDF is a fixed-layout format, while HTML is a flow-based format. Complex PDF layouts, scanned pages, and heavily visual documents may require manual review, depending on your output quality requirements.
Compare PDF-to-HTML and data extraction
PDF-to-HTML conversion works well when you need HTML output from a document conversion workflow. If you need layout-aware structured extraction, bounding boxes, key-value pairs, tables, schema-shaped JSON, or Markdown for retrieval-augmented generation (RAG) pipelines, use the DWS Data Extraction API.
Combine PDF-to-HTML with other processing
The /build endpoint can assemble or prepare a PDF before it converts the file to HTML. For example, you can merge multiple PDFs and convert the merged output to HTML.
Use this instructions object to merge two PDFs and convert them to HTML:
{ "parts": [ { "file": "cover" }, { "file": "body" } ], "output": { "type": "html", "layout": "page" }}You can also extract selected pages before conversion with parts[].pages.
Reference
A PDF-to-HTML request uses the Build API output object with HTML output:
type HTMLOutput = { type: "html",
// The layout type to use for HTML conversion. layout?: "page" | "reflow",};
type FilePart = { // Multipart field name, or a remote URL object. file: string | { url: string },
// Optional password for encrypted input PDFs. password?: string,
// Optional page range to convert. pages?: { start?: number, end?: number, },};
type BuildInstructions = { parts: FilePart[], output: HTMLOutput,};Related API reference operations
- Refer to the build document endpoint API reference to convert PDFs to HTML and combine conversion with page selection or document assembly.
Related guides
- Refer to the PDF-to-Markdown API guide.
- Refer to the PDF-to-Office API guide.
- Refer to the PDF-to-image API guide.
- Refer to the PDF OCR API guide.
- Refer to the PDF merge API guide.
- Refer to the PDF split API guide.
- Refer to the tools and APIs guide.