Pexels vs ReSmush.it

Pexels' JSON API serves its library of free stock photos and videos for keyword search, curated collections, and per-item lookups, with photo results carrying several pre-generated JPEG sizes ready to use without further processing. A personal key sent via the Authorization header is the only credential required — no OAuth flow — and a live probe of the search endpoint showed a 25,000-request rate-limit window tracked per key rather than per IP. There is no paid tier: under the Pexels License, images and videos are free for personal and commercial use, with attribution appreciated but not required.

ReSmush.it is a free, keyless image-optimization API — best known as the backend behind the ReSmush.it WordPress plugin — that accepts a source image URL and returns a JSON payload with the compressed image's URL plus original size, compressed size, and percent reduction. A live call against api.resmush.it needed no credentials and returned Access-Control-Allow-Origin: *, so it works directly from browser JavaScript. The plain http:// endpoint immediately redirects to https, so the service is https-only despite requiring no API key.