11 Free APIs Every Developer Should Bookmark (No Signup Required)

Every developer needs a handful of utility APIs — the kind you reach for when building prototypes, debugging integrations, or automating workflows. Here are 11 free ones I built. No signup, no API key, no rate limit surprises. 1. HTML to PDF Converter Convert any HTML to a clean PDF. Supports A4, Letter, Legal page sizes. curl -X POST https://documint.anethoth.com/api/v1/html-to-pdf -H "Content-Type: application/json" -d '{"html": " Hello World This becomes a PDF. "}' --output result.pdf 2. Mark