PDF to HTML in Node.js

Overview

Convert PDF documents to HTML from server-side Node.js code using the PDFCrowd client. Conversions run on PDFCrowd's servers.

Installation

This guide uses SDK 7 or later, supported on Node.js 18 and later. Install the client with npm, or see other installation options.

npm install pdfcrowd

See upgrading to SDK 7 when updating an existing installation.

Quick Start

You can run the examples below with the displayed API credentials. Update the input URLs and filenames as needed.

const pdfcrowd = require('pdfcrowd');

import * as pdfcrowd from 'pdfcrowd';

import pdfcrowd = require('pdfcrowd');

import pdfcrowd from 'pdfcrowd';

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");
    
    const filePath = await client.convertUrlToFile(
        "https://your-server.com/invoice.pdf", "invoice.html"
    );
    console.log("Saved:", filePath);
} catch (error) {
    // Handle the error in your application.
    console.error(String(error));
}

import pdfcrowd from 'pdfcrowd';

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");
    
    client.convertUrlToFile(
        "https://your-server.com/invoice.pdf", "invoice.html",
        (error, filePath) => {
            if (error) {
                // Handle the error in your application.
                console.error(error.toString());
                return;
            }
            console.log("Saved:", filePath);
        }
    );
} catch (error) {
    // Handle the error in your application.
    console.error(String(error));
}

import pdfcrowd from 'pdfcrowd';

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");
    
    const filePath = await client.convertFileToFile("logo.pdf", "logo.html");
    console.log("Saved:", filePath);
} catch (error) {
    // Handle the error in your application.
    console.error(String(error));
}

import pdfcrowd from 'pdfcrowd';

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");
    
    client.convertFileToFile("logo.pdf", "logo.html", (error, filePath) => {
        if (error) {
            // Handle the error in your application.
            console.error(error.toString());
            return;
        }
        console.log("Saved:", filePath);
    });
} catch (error) {
    // Handle the error in your application.
    console.error(String(error));
}

Configure a Conversion

Authentication

Pass your PDFCrowd username and API key to PdfToHtmlClient. Find your credentials on the API Keys page.

Choose an Input

Send a PDF URL, upload a local file, or pass PDF bytes or a readable binary stream.

Add Conversion Settings

Set conversion options on the client before calling a conversion method. For example, client.setScaleFactor(150); enlarges the HTML page layout by a factor of 1.5.

Common settings are listed below. See the method reference for all available options or browse Node.js examples.

The PDF password unlocks the input document; it is separate from your PDFCrowd API key.

Handle the Result

Choose an Output

By default, images, CSS and fonts are embedded in a single HTML file. The result preserves the PDF page layout; it does not reconstruct the original source HTML or create a responsive design.

The methods below use URL input; local files, bytes, and input streams have corresponding methods.

For large results, file or stream output avoids collecting the entire result in memory. When saving a stream, wait for pipeline to finish and handle any error before using the file. See the stream examples.

For return values and completion rules, see Promise results and Callbacks in the reference.

This example converts a PDF to HTML, collects the result in a Buffer, and saves it locally as invoice.html:

import pdfcrowd from 'pdfcrowd';
import fs from 'node:fs';

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");

    function saveResult(result) {
        fs.writeFileSync("invoice.html", result);
    }

    const result = await client.convertUrl("https://your-server.com/invoice.pdf");
    saveResult(result);
} catch (error) {
    // Handle the error in your application.
    console.error(String(error));
}

import pdfcrowd from 'pdfcrowd';
import fs from 'node:fs';

function handleError(error) {
    // Handle the error in your application.
    console.error(String(error));
}

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");

    function saveResult(result) {
        fs.writeFileSync("invoice.html", result);
    }

    const chunks = [];
    let failed = false;
    client.convertUrl("https://your-server.com/invoice.pdf", {
        data: (stream) => stream.on('data', (chunk) => chunks.push(chunk)),
        error: (message, statusCode) => {
            failed = true;
            handleError(new pdfcrowd.Pdfcrowd.Error(message, statusCode));
        },
        end: () => {
            if (failed) return;
            try {
                saveResult(Buffer.concat(chunks));
            } catch (error) {
                handleError(error);
            }
        }
    });
} catch (error) {
    handleError(error);
}

Setting an image, CSS or font mode to "separate" produces a ZIP archive with the HTML and its resources. Save that result with a .zip extension, then extract it while retaining the relative directory structure. isZippedOutput() reports whether the selected settings produce a ZIP archive.

When serving the result from a web application, use text/html; charset=utf-8 for HTML or application/zip for an archive.

Handle Errors

Use try/catch around awaited conversions. In callback mode, handle errors in the callback and catch synchronous validation errors from the initial call. This example converts a PDF to HTML, logging the HTTP status and reason code when available:

import pdfcrowd from 'pdfcrowd';

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");

    const filePath = await client.convertUrlToFile(
        "https://your-server.com/invoice.pdf", "invoice.html"
    );
    console.log("Saved:", filePath);
} catch (error) {
    // Handle the error in your application.
    if (error instanceof pdfcrowd.Pdfcrowd.Error) {
        console.error("PDFCrowd error:", error.getStatusCode(),
            error.getReasonCode(), error.getMessage());
    } else {
        console.error(String(error));
    }
}

import pdfcrowd from 'pdfcrowd';

function handleError(error) {
    // Handle the error in your application.
    if (error instanceof pdfcrowd.Pdfcrowd.Error) {
        console.error("PDFCrowd error:", error.getStatusCode(),
            error.getReasonCode(), error.getMessage());
    } else {
        console.error(String(error));
    }
}

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");

    client.convertUrlToFile(
        "https://your-server.com/invoice.pdf", "invoice.html",
        (error, filePath) => {
            if (error) {
                handleError(error);
                return;
            }
            console.log("Saved:", filePath);
        }
    );
} catch (error) {
    handleError(error);
}

For stream output, handle errors both when obtaining the stream and when consuming it. A pipeline reports failures while reading the response or writing the destination.

Conversion errors use pdfcrowd.Pdfcrowd.Error. Local file and stream operations can also produce native errors; check the error type before using SDK-specific methods.

See the error-object reference for status, reason, and message accessors.

The SDK error's toString() includes available status and reason codes. Use String(error) when logging an error of either type.

Common Status Codes

See all status and reason codes for specific explanations and Limits and Retries for retry behavior.

For job IDs, credit usage, and other conversion details, see the reference.

Limits and Retries

Request rate and concurrency limits depend on your license. Control how quickly your application submits conversions and how many it runs at once. A 429 response concerns request rate; a 430 response concerns requests already in progress. The maximum upload size is 300 MB.

The Node.js client automatically retries a request once when it receives HTTP 502 or 503. Use setRetryCount() to change that count, or set it to 0 to disable automatic retries. Account for these retries when adding an application-level retry policy.

Troubleshooting

Inspect a Conversion

This example converts a PDF to HTML with debug logging enabled and logs the debug log URL when available. Use the input and settings from the conversion you are investigating.

import pdfcrowd from 'pdfcrowd';

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");

    try {
        client.setDebugLog(true);
        await client.convertUrlToFile("https://your-server.com/invoice.pdf", "invoice.html");
    } finally {
        const debugLogUrl = client.getDebugLogUrl();
        if (debugLogUrl) console.info("Debug log:", debugLogUrl);
    }
} catch (error) {
    // Handle the error in your application.
    console.error(String(error));
}

import pdfcrowd from 'pdfcrowd';

function handleError(error) {
    // Handle the error in your application.
    console.error(String(error));
}

try {
    const client = new pdfcrowd.PdfToHtmlClient("demo", "demo");

    function finish(error) {
        if (error) handleError(error);
        const debugLogUrl = client.getDebugLogUrl();
        if (debugLogUrl) console.info("Debug log:", debugLogUrl);
    }

    try {
        client.setDebugLog(true);
        client.convertUrlToFile("https://your-server.com/invoice.pdf", "invoice.html", finish);
    } catch (error) {
        finish(error);
    }
} catch (error) {
    handleError(error);
}

The debug log contains conversion settings and processing details. You can also find logs in your conversion history. A local or connection failure may occur before a conversion log is available.

Common Problems

For help, contact support and include any available diagnostics, the client version, and enough detail to reproduce the problem.

Upgrading to SDK 7

The methods below were removed in SDK 7. For changes to Promise and callback usage, see the general upgrade notes.