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The Complete Guide to PDF Generation in Node.js

Node.js is perfect for I/O-heavy tasks like PDF generation. Explore the best libraries and patterns for building a scalable document service.

Node.js logo interacting with a stream of PDF documents

The Complete Guide to PDF Generation in Node.js

Node.js is the runtime of choice for modern web backends. Its non-blocking I/O model makes it ideal for handling document generation services that might need to wait for database queries or external APIs.

  • PDFKit: The grandfather of Node PDF libraries. It’s a low-level imperative API (doc.text('Hello', 100, 100)). Great for speed, hard for complex layouts.
  • Puppeteer: Headless Chrome. You write HTML/CSS, and Chrome “prints” it to PDF.
    • Pros: You can use Flexbox/Grid.
    • Cons: Heavy memory usage. Running a browser instance for every PDF is expensive.
  • React-PDF: Allows you to build PDFs using React components. Great if you want to share UI code between web and print.

2. Performance Considerations

Generating a PDF is CPU intensive.

  • Don’t block the Event Loop: If you use a synchronous library to generate a 100-page report, your entire Node server will freeze.
  • Streams: Always use Streams. Pipe the PDF output directly to the HTTP response or S3 bucket. Do not buffer the whole file in RAM.

3. Serverless (AWS Lambda)

Node.js PDF generation fits perfectly in Serverless.

  • Cold Starts: Puppeteer can be slow to start on Lambda.
  • Layers: You may need to use special Lambda Layers to get the necessary fonts and binaries (like libfontconfig) available in the cloud environment.

Conclusion

Node.js offers a rich ecosystem for PDF generation, from low-level drawing tools to high-level HTML converters.

Node.js Native. MergeCanvas provides a robust Node.js SDK to integrate high-performance document generation into your application in minutes.