Collins vs Lingua Robot

Collins' REST API serves the publisher's monolingual English and bilingual dictionary, thesaurus, translation and audio-pronunciation data used on collinsdictionary.com, with separate JSON and XML response representations for each resource. A live unauthenticated request against the real gateway returned a genuine application-level "NoAccessKey" 403 rather than a Cloudflare challenge, confirming the API Key requirement and that the service itself is fully live. Its own pricing page grants up to 5,000 calls/month free before metered tiers (from £50/month) kick in at higher volumes.

Lingua Robot is a RapidAPI-hosted REST dictionary covering more than 800,000 English lexical entries — words, phrasal verbs, and multiword expressions — with definitions, pronunciations, and morpheme/lemma data returned as JSON, documented on a separate Apiary reference site rather than its own marketing homepage. A live unauthenticated request against its real RapidAPI proxy host returned a reflected `access-control-allow-origin` header plus `access-control-allow-credentials: true`, reconfirming CORS; its free Basic tier covers 2,500 requests/day (then $0.004 each), with paid Pro/Ultra/Mega plans ($10-$99/month) raising the daily ceiling.