Can I convert HTML to PDF with curl without an API key?

Yes. POST /v1/render works anonymously at 10 requests per minute per IP, so a single curl call needs no signup. Sending an X-API-Key header raises that limit and draws on your monthly credits instead.

What is the maximum HTML size a curl request can send?

2 MiB of UTF-8 HTML over REST. Larger payloads are rejected with 413 html_too_large. Because images and fonts must be inlined as data: URIs, that budget is usually spent on assets rather than markup.

How do I save the PDF to a file with curl?

The response body is the raw PDF, so redirect it: add --output invoice.pdf to the curl call. The optional filename field in the JSON body only sets the Content-Disposition name.

Convert HTML to PDF with curl

Render HTML to PDF from the command line with one curl call. Works anonymously — an API key raises the rate limit. Full request and limits.

Last updated 2026-07-26

Endpoint	POST /v1/render (JSON: html required, filename optional)
Anonymous calls	allowed, rate-limited per IP (10/minute)
Limits	2 MiB of HTML, 50 pages, 20 s render timeout

The whole API is one endpoint: POST /v1/render takes a JSON body with your HTML and streams back the PDF. No SDK required — it works from a terminal in one command, with or without an API key:

curl -X POST https://api.pdfrender.dev/v1/render \
  -H 'Content-Type: application/json' \
  -d '{"html": "<h1>Hello</h1><p>Rendered by pdfrender.</p>", "filename": "hello.pdf"}' \
  -o hello.pdf

html is a complete HTML string; filename (optional, default document.pdf) sets the download filename in the Content-Disposition header. The response is application/pdf bytes — -o writes them straight to disk.

With an API key

Add the key as a header. A valid key lifts you from the anonymous per-IP limit to your plan's budget and meters one credit per render:

curl -X POST https://api.pdfrender.dev/v1/render \
  -H 'Content-Type: application/json' \
  -H 'X-API-Key: YOUR_KEY' \
  -d @request.json \
  -o out.pdf

A missing or invalid key is not an error — the call simply stays anonymous. Inline images, fonts and CSS as data: URIs; external http(s) resources are never fetched (a document that references one is rejected with 400 listing the URLs), and no JavaScript runs.

Try it free

Try it free — 100 renders a month, no card — or paste HTML into the browser-based free HTML→PDF tool, no signup at all.

FAQ

Can I convert HTML to PDF with curl without an API key?: Yes. POST /v1/render works anonymously at 10 requests per minute per IP, so a single curl call needs no signup. Sending an X-API-Key header raises that limit and draws on your monthly credits instead.
What is the maximum HTML size a curl request can send?: 2 MiB of UTF-8 HTML over REST. Larger payloads are rejected with 413 html_too_large. Because images and fonts must be inlined as data: URIs, that budget is usually spent on assets rather than markup.
How do I save the PDF to a file with curl?: The response body is the raw PDF, so redirect it: add --output invoice.pdf to the curl call. The optional filename field in the JSON body only sets the Content-Disposition name.