Free Dictionary API vs Wiktionary API

Two free Dictionaries APIs compared on access, reliability and developer ratings, using data from our daily health checks.

The verdict

	Free Dictionary API	Wiktionary API
What it does	Definitions, phonetics, pronunciations, parts of speech, examples, synonyms.	Collaborative dictionary data. A free dictionaries API by Wiktionary.
Provider	Free Dictionary API	Wiktionary
API key	Not needed	Not needed
HTTPS	Yes	Yes
CORS (browser calls)	Unknown	Yes
Status today	Online · 620 ms	Online · 942 ms
Uptime (30 days)	Up	Up
Developer rating	Not rated yet	Not rated yet
Price	Free / free tier	Free / free tier

Definitions, phonetics, pronunciations, parts of speech, examples, synonyms.

Strengths

Collaborative dictionary data. A free dictionaries API by Wiktionary.

Strengths

Prototyping or a tutorial? Pick the one that needs no API key (both qualify).
Calling from a web page? You need CORS. Otherwise route requests through your own server or a serverless function.
Going to production? Favour HTTPS, a strong uptime record and a provider with clear rate limits and terms. Check each API's docs before you commit.
Still unsure? Both are free to try: send one request to each and compare the data you get back.

Neither needs an API key; you can call both straight away.

Wiktionary API supports CORS, so front-end JavaScript can call it directly. Call the other from a server.