--- title: MFA, Blocking functions, and more come to Firebase... description: Firebase Authentication introduces an optional upgrade called Firebase Authentication with Identity Platform, adding multi-factor authentication (SMS-based... canonical: https://daily.dev/posts/mfa-blocking-functions-and-more-come-to-firebase-authentication-hlg9cdlxa twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: MFA, Blocking functions, and more come to Firebase Authentication | daily.dev og:description: Firebase Authentication introduces an optional upgrade called Firebase Authentication with Identity Platform, adding multi-factor authentication (SMS-based... og:url: https://daily.dev/posts/mfa-blocking-functions-and-more-come-to-firebase-authentication-hlg9cdlxa og:image: https://api.daily.dev/og/posts/HlG9CDLxA.png og:image:alt: MFA, Blocking functions, and more come to Firebase Authentication og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # MFA, Blocking functions, and more come to Firebase Authentication **[Firebase](https://daily.dev/sources/firebase-blog)** · 7 min read · 0 upvotes · 0 comments ## Summary Firebase Authentication introduces an optional upgrade called Firebase Authentication with Identity Platform, adding multi-factor authentication (SMS-based second factor), Blocking Functions that run custom logic during sign-up/sign-in, support for SAML and OpenID Connect providers, improved user activity and audit logging, multi-tenancy, and enterprise support with SLAs. The upgrade requires no migration, can be enabled with one click in the Firebase console, and includes a no-cost tier limited to 3,000 daily active users (Spark plan) or 50,000 monthly active users free on the pay-as-you-go Blaze plan before charges apply. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I add multi-factor authentication to my Firebase app? Firebase Authentication with Identity Platform, an optional no-migration upgrade enabled with one click in the Firebase console, adds SMS-based multi-factor authentication. MFA support rolls out in the next releases of FirebaseUI for iOS, Android, Web, and Flutter, or developers using the Auth SDKs directly can add it manually following Apple, Android, and web platform guides. _daily.dev surfaces practical guides for developers rolling out MFA across their Firebase apps._ ### What are Blocking Functions in Firebase Authentication and what can they do? Blocking Functions are Cloud Functions that execute during sign-up or sign-in and must finish running before authentication completes, letting developers enforce custom constraints such as restricting sign-ups to a specific email domain, checking a user's location, or adding custom claims based on reputation score. They replace the need to build a custom auth server that exchanges tokens with Firebase Auth. _Developers customizing sign-in flows can track new auth capabilities like this via daily.dev._ ### What are the usage limits for the upgraded Firebase Authentication with Identity Platform? Upgraded projects on the no-cost Spark plan are limited to 3,000 daily active users, while pay-as-you-go Blaze plan projects get a no-cost tier of 50,000 monthly active users before usage-based charges apply. The upgrade adds no-cost multi-factor authentication, blocking functions, and multi-tenancy without requiring a payment method for most projects. _Teams weighing Firebase Auth pricing tiers can follow platform pricing changes on daily.dev._ ## Similar posts on daily.dev - [Stop Building MFA from Scratch \(And What to Do Instead\)](https://daily.dev/posts/stop-building-mfa-from-scratch-and-what-to-do-instead--vz6u10998) · Auth0 · 1 upvotes · 0 comments - [Flexible Authentication: Reimagining authentication for millions of users at Airbnb](https://daily.dev/posts/flexible-authentication-reimagining-authentication-for-millions-of-users-at-airbnb-cl9wjogbt) · Airbnb · 0 upvotes · 0 comments - [Mind the gap: new tools for continuous enforcement from boot to login](https://daily.dev/posts/mind-the-gap-new-tools-for-continuous-enforcement-from-boot-to-login-ewupaapdj) · Cloudflare · 0 upvotes · 0 comments - [Signing In to Online Accounts](https://daily.dev/posts/signing-in-to-online-accounts-sdtdy1xlv) · Security Boulevard · 0 upvotes · 0 comments --- Tags: [#authentication](https://daily.dev/tags/authentication), [#firebase](https://daily.dev/tags/firebase), [#gcp-cloud-functions](https://daily.dev/tags/gcp-cloud-functions) [View this post on daily.dev](https://daily.dev/posts/mfa-blocking-functions-and-more-come-to-firebase-authentication-hlg9cdlxa) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"MFA, Blocking functions, and more come to Firebase Authentication","url":"https://daily.dev/posts/mfa-blocking-functions-and-more-come-to-firebase-authentication-hlg9cdlxa","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/mfa-blocking-functions-and-more-come-to-firebase-authentication-hlg9cdlxa"},"datePublished":"2026-08-23T12:20:37.100Z","dateModified":"2026-08-23T12:31:40.760Z","description":"Firebase Authentication introduces an optional upgrade called Firebase Authentication with Identity Platform, adding multi-factor authentication (SMS-based...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/f0a25f6326f1f2cf7805b9d5ec0599a9?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/f0a25f6326f1f2cf7805b9d5ec0599a9?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Firebase","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Firebase","logo":"https://media.daily.dev/image/upload/s--i395oqZH--/f_auto,q_auto/v1787487448/logos/firebase-blog?_a=BAMAMicg0","url":"https://daily.dev/sources/firebase-blog"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/mfa-blocking-functions-and-more-come-to-firebase-authentication-hlg9cdlxa","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"authentication,firebase,gcp-cloud-functions","timeRequired":"PT7M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Firebase","item":"https://daily.dev/sources/firebase-blog"},{"@type":"ListItem","position":3,"name":"MFA, Blocking functions, and more come to Firebase Authentication"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/mfa-blocking-functions-and-more-come-to-firebase-authentication-hlg9cdlxa#faq","mainEntity":[{"@type":"Question","name":"How do I add multi-factor authentication to my Firebase app?","acceptedAnswer":{"@type":"Answer","text":"Firebase Authentication with Identity Platform, an optional no-migration upgrade enabled with one click in the Firebase console, adds SMS-based multi-factor authentication. 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