What is a PDF generation API?

A PDF generation API is a web service that turns HTML, a URL, or a template combined with JSON data into a downloadable PDF file through a single API call. Instead of building PDF rendering logic yourself, an application sends a request and receives a finished PDF back.

Why it exists

Rendering a pixel-accurate PDF is harder than it looks: fonts need to be embedded, page breaks need to respect content, and CSS layout has to be evaluated by an actual rendering engine, not approximated. A PDF generation API centralizes that work — it runs a rendering engine (commonly a headless browser like Chromium) on the server side, so any application, script, or agent that can make an HTTP request can produce a correctly formatted PDF without embedding a browser or a print pipeline of its own.

This is distinct from a client-side PDF library, which runs inside your own application process and leaves layout, fonts, and pagination as your responsibility. It is also distinct from a desktop “print to PDF” feature, which is manual and not callable by another program. A PDF generation API is built to be called programmatically — from a backend, a no-code automation, or an AI agent — and to return the same output every time for the same input.

How it works

The typical flow is: your application sends a source (HTML, a URL, or a template ID with data) to the API; the service renders that source with a real browser engine; the resulting PDF bytes are returned in the response, or a link to download them. An idempotencyKey is often supported so retried requests do not generate the document twice.

curl https://docweave.dev/api/v1/pdf \
  -H "Authorization: Bearer dw_live_your_key" \
  -H "Content-Type: application/json" \
  -H "Accept: application/pdf" \
  -d '{
    "source": { "type": "html", "html": "<h1>Invoice #1024</h1>" },
    "options": { "format": "A4", "margin": "20mm" },
    "idempotencyKey": "invoice-1024-attempt-1"
  }' \
  --output invoice.pdf

The same idea works as an MCP tool for AI agents. With Docweave’s open-source MCP server (npx @docweave/mcp), an agent calls a single generate_pdf tool instead of writing HTTP code, and gets a PDF back as part of its tool-call loop.

How Docweave relates to this

Docweave is a PDF generation API: one REST call to POST /api/v1/pdf accepts HTML, a URL, or a template + JSON, renders it with Chromium, and returns a PDF. It is priced per document rather than per page, supports an idempotencyKey so retries never double-bill or double-generate, and ships an open-source MCP server so AI agents can call it as a native tool rather than hand-rolling HTTP requests.

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