Mahiuddin Al Kamal

Posted on Jun 21

Generate Invoice PDFs from HTML in 10 Lines of Code

#javascript #pdf #webdev #api

I got tired of running headless Chrome myself just to turn HTML invoices into PDF attachments. So I built a small API and listed it on RapidAPI: Simple PDF API.

Free tier included. No browser setup on your side.

The problem

Every SaaS eventually needs PDFs:

Invoices and receipts
Reports and exports
Downloadable confirmations

The usual options:

Run Puppeteer/Playwright yourself — works, but ops pain (memory, crashes, scaling)
Enterprise PDF APIs — great, but $15–75/mo before you have revenue
wkhtmltopdf — dated CSS support

I wanted: JSON in → PDF bytes out. One POST. Done.

The solution

curl --request POST \
  --url "https://simple-pdf-api.p.rapidapi.com/v1/html-to-pdf" \
  --header "Content-Type: application/json" \
  --header "X-RapidAPI-Key: YOUR_KEY" \
  --header "X-RapidAPI-Host: simple-pdf-api.p.rapidapi.com" \
  --data '{
    "html": "<html><body><h1>Invoice #1042</h1><p>Total: $99.00</p></body></html>",
    "page_size": "A4"
  }' \
  --output invoice.pdf

That's it. You get raw application/pdf bytes back.

JavaScript example

const res = await fetch("https://simple-pdf-api.p.rapidapi.com/v1/html-to-pdf", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "X-RapidAPI-Key": process.env.RAPIDAPI_KEY,
    "X-RapidAPI-Host": "simple-pdf-api.p.rapidapi.com",
  },
  body: JSON.stringify({
    html: invoiceHtml,
    page_size: "A4",
  }),
});

const pdf = Buffer.from(await res.arrayBuffer());
// attach to email, upload to S3, etc.

Python example

import requests

resp = requests.post(
    "https://simple-pdf-api.p.rapidapi.com/v1/html-to-pdf",
    headers={
        "X-RapidAPI-Key": "YOUR_KEY",
        "X-RapidAPI-Host": "simple-pdf-api.p.rapidapi.com",
    },
    json={"html": invoice_html, "page_size": "A4"},
    timeout=90,
)
resp.raise_for_status()

with open("invoice.pdf", "wb") as f:
    f.write(resp.content)

What else is included

Same API key, same subscription:

HTML or URL → PDF — full CSS via headless Chromium
Merge PDFs — combine multiple documents
Split PDF — extract page ranges
Watermark — add CONFIDENTIAL / DRAFT overlays
Compress — reduce file size by removing duplicate objects
Protect — AES password-encrypt with configurable print permissions
Rotate — rotate all or selected pages by 90, 180, or 270°
Extract text — pull plain text for search/indexing

8 endpoints, one API key.

Pricing

Plan	Price	Quota
BASIC	Free	~50 req/day
PRO	$9/mo	5,000 req/mo
ULTRA	$29/mo	25,000 req/mo

Enough free tier to test. PRO is priced for indie devs and early-stage SaaS.

Try it

Subscribe on RapidAPI (free plan)
Copy your API key
Paste the curl above
Open invoice.pdf

Interactive API docs: https://pdf-api-production-9570.up.railway.app/docs

Built with FastAPI + Playwright. Happy to answer integration questions in the comments.

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