Firebase Authentication is Google's backend for sign-in with passwords and identity providers.
About 10,974 websites in the PageSourceSearch index contain the code that reveals it; the 50 highest-ranked are listed below.
How is Firebase Authentication detected?
Pages load firebase-auth.js (or firebase-auth-compat.js) from www.gstatic.com/firebasejs/. The discovery keyword is the exact bytes PageSourceSearch looks for in every stored page and script:
A literal is matched byte for byte, case-sensitively. Combine it with another keyword, a domain, a kind or a date filter on the search page to narrow the list. About Firebase Authentication
Top 50 websites using Firebase Authentication
Ranked by the domain's position in the crawl's ranked list (Common Crawl harmonic centrality), highest first. view source opens the stored page or script with the match highlighted. Computed 2026-09-29 16:05:02 UTC.
How does PageSourceSearch know a website uses Firebase Authentication?
By the source itself: Pages load firebase-auth.js (or firebase-auth-compat.js) from www.gstatic.com/firebasejs/. PageSourceSearch stores the raw HTML and first-party JavaScript of each crawled site and matches the keyword byte for byte, so every listed site's stored source contains it.
Is this a complete list of websites using Firebase Authentication?
No. The page lists the 50 highest-ranked sites in the index whose source holds the keyword, out of about 10,974 websites that do; the count is the index's estimate at the time the list was computed. Run the keyword as a search to page through all of them, or add a kind or date filter.
How do I find websites that use Firebase Authentication together with another technology?
Search for both keywords at once: several terms separated by spaces must all be found on the same site, or with the Same page toggle in the same page. For example firebase-auth with wp-content/plugins/ lists the WordPress sites that use Firebase Authentication.