Featherpress API

Turn HTML or Markdown into a pixel-perfect PDF with a single HTTP request. No headless Chrome — a purpose-built renderer, edge-ready.

The API has one base URL and a tiny surface area: JSON in, a PDF (or JSON) out. Every request is authenticated with an API key.

Quickstart

Grab a key from the dashboard, then POST some HTML. The response body is the raw PDF.

curl -X POST "https://api.featherpress.dev/v1/render" \
  -H "X-API-Key: rk_live_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"input_type": "html", "content": "<h1>Hello, world!</h1>"}' \
  --output hello.pdf

A 200 streams back application/pdf. That is the whole loop.

Authentication

Pass your key in the X-API-Key header on every request. Keys look like rk_live_… and are shown in full only once, at creation time. Only a SHA-256 hash is stored.

X-API-Key: rk_live_k3yX9aR2mB7nQ4vL8Kq2

Render a PDF

Renders content (HTML or Markdown) into a PDF (Content-Type: application/pdf).

Body parameters

Add ?strict=true to reject HTML that uses unsupported constructs with a 422 (the validator findings, below) instead of rendering it.

Request

import { writeFile } from "node:fs/promises";

const res = await fetch("https://api.featherpress.dev/v1/render", {
  method: "POST",
  headers: {
    "X-API-Key": "rk_live_your_api_key",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    input_type: "html",
    content: "<h1>Hello, world!</h1>",
  }),
});

if (!res.ok) throw new Error(`Render failed: ${res.status}`);
await writeFile("hello.pdf", Buffer.from(await res.arrayBuffer()));

Response

On success the body is the binary PDF. Every response carries an x-request-id you can quote when reporting an issue:

HTTP/2 200
content-type: application/pdf
x-request-id: 1a01b4ca-ad32-461b-9119-1a32a07802a1

Validate a document

Statically lints content for the engine's CSS-subset blind spots without rendering it — and without spending a conversion. Returns { ok, findings }; each finding has a rule, severity (error or warn), message, and suggestion.

curl -X POST "https://api.featherpress.dev/v1/validate" \
  -H "X-API-Key: rk_live_…" \
  -H "Content-Type: application/json" \
  -d '{"content": "<div style=\"background: var(--brand)\">Hi</div>"}'

# 200 OK
{
  "ok": false,
  "findings": [
    {
      "rule": "css-var-unsupported",
      "severity": "error",
      "message": "CSS custom property var() is not resolved; the property is silently dropped.",
      "suggestion": "Inline the literal value instead of var(--x).",
      "snippet": "background: var(--brand)"
    }
  ]
}

Supported CSS

Errors

Errors return a JSON body with a human-readable error message and the numeric code:

{
  "error": "API key is missing or invalid.",
  "code": 401
}

Limits

The Free plan includes 5,000 conversions per month. Each successful /v1/render counts as one conversion; /v1/validate is free and never counts. When your monthly quota is exhausted the API responds 402.

Track live usage and latency in your dashboard. No SDK is required — call the HTTP API from any language (see integration examples). First-party client libraries are planned.