Dictionaries · head-to-head
Collins vs Merriam-Webster
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.
Merriam-Webster's Dictionary API returns JSON definitions, pronunciations, and audio from the publisher's own Collegiate Dictionary and Thesaurus, plus specialized editions covering medical, learner's, Spanish-English, and grade-banded school dictionaries, each requiring a separate free API key. Keys are issued under a strict non-commercial license capped at 1,000 queries/day/key; using the service in a commercial product requires a separately negotiated agreement with Merriam-Webster.
| Collins | Merriam-Webster | |
|---|---|---|
| Authentication | API Key | API Key |
| Pricing | freemium | free |
| Formats | JSON, XML | JSON |
| CORS | no | yes |
| HTTPS | Yes | Yes |
Merriam-Webster supports CORS, while Collins doesn't — pick Merriam-Webster for direct browser calls.