Generate PDFs in Next.js

Generate a PDF in Next.js

POST your HTML and data to /api/v1/generate with your API key, then save the PDF that comes back. Swap in your own HTML or a saved template_id and loop over records to render at scale.

// app/api/invoice/route.ts
export async function GET() {
  const res = await fetch("https://pdfgen.com/api/v1/generate", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.PDFGEN_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      html: "<h1>Invoice {{number}}</h1><p>Billed to {{client}} — total {{total}}</p>",
      engine: "handlebars",
      format: "A4",
      data: { number: "INV-001", client: "Acme Corp", total: "$2,400.00" },
    }),
  });

  return new Response(await res.arrayBuffer(), {
    headers: {
      "Content-Type": "application/pdf",
      "Content-Disposition": "inline; filename=invoice.pdf",
    },
  });
}

Convert existing HTML to PDF in Next.js

Already have finished HTML? Skip templating — POST HTML to a Route Handler and stream the PDF back and send it with engine: "legacy", which tells the API your markup is final.

// app/api/html-to-pdf/route.ts
export async function POST(req: Request) {
  const html = await req.text(); // the HTML you want to convert

  const res = await fetch("https://pdfgen.com/api/v1/generate", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.PDFGEN_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ html, engine: "legacy", format: "A4" }),
  });

  return new Response(await res.arrayBuffer(), {
    headers: { "Content-Type": "application/pdf" },
  });
}

How it works

1. 1

   Send your HTML + data

   POST an HTML template (with optional Handlebars tokens) and a data object to the API.

2. 2

   We render the PDF

   PDFgen renders it server-side — no headless browser for you to run or scale.

3. 3

   Get the PDF back

   Receive the PDF binary (or a hosted link with export_type:"url") and serve it from Next.js.

Good to know

• Put the call in a Route Handler / API route so PDFGEN_API_KEY never reaches the client bundle.
• Returning the arrayBuffer with a PDF content type lets the browser preview or download it directly.
• No headless Chrome to bundle — this stays well under serverless function size limits.

Frequently asked questions

Where should the PDF call live in Next.js?

In a server-side Route Handler (app/api/.../route.ts) or pages/api route. That keeps your API key on the server and avoids shipping it to the browser.

Can I generate the PDF in a Server Action?

Yes — call /api/v1/generate from a Server Action the same way; return the bytes or upload them, since you can’t stream a file download directly from an action.

Does this work on Vercel / serverless?

Yes. Because rendering happens on PDFgen, there’s no headless browser to bundle, so it stays within serverless size and memory limits.

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