Google Safe Browsing vs MalwareBazaar

Google Safe Browsing lets clients check URLs against Google's continuously updated lists of malware, phishing, and unwanted-software sites via the v4 threatMatches:find endpoint, the same data that powers warnings in Chrome and Search. A live POST with a syntactically valid but bogus key returned a 400 "API key not valid" error from safebrowsing.googleapis.com, reconfirming API-key auth and HTTPS, and both that call and its OPTIONS preflight echoed the request Origin in Access-Control-Allow-Origin. The API is free for any Google Cloud project under its published quota.

MalwareBazaar, part of the abuse.ch threat-intel suite, is a community platform for submitting, tagging, and bulk-downloading real malware samples by hash, signature family, or YARA rule via its JSON API. A live POST to the real mb-api.abuse.ch host without an Auth-Key was rejected, and a bogus key returned {"query_status": "unknown_auth_key"}, confirming abuse.ch's mandatory Auth-Key authentication over HTTPS with no Access-Control-Allow-Origin header on either response. Use is free under abuse.ch's fair-use policy, with a separate paid commercial API tier for organizations needing higher volume or an SLA.