Free Security APIs
Threat intel, breach checks and validation utilities. Keyless tiers only. 18 of 22 on our probe schedule.
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Free Security APIs — FAQ
Are there free Security APIs with no API key?
Yes — 12 of the 22 free security APIs we list need no API key or signup (EmailRep is a good starting point). Use the "No key" filter above to see them; they're the fastest to prototype with.
Which free Security API is the most reliable?
Of the 22 security APIs on our probe schedule, EmailRep leads on measured uptime (100% over 90 days). Reliability here is verified from our own scheduled checks, not the provider's claims — sort by "Reliable" to rank the rest.
Can I call these Security APIs from the browser?
8 of these security APIs send CORS headers over HTTPS, so you can fetch them straight from front-end code — no backend proxy. Filter by "Browser OK" to see them; the rest need a server-side call.
Are these free Security APIs OK for commercial use?
3 of the 22 security APIs allow commercial use on the free tier; the rest are unclear or personal-only. We record service terms and the data license as separate fields on every listing — check both before you ship.
How often are these Security APIs checked?
18 of the 22 security APIs are on our probe schedule and re-tested every sweep. We log uptime, latency and response-shape changes on each, and move any that stay down to the graveyard so you can see what died and when.