Firebase Auth or Sendora — pick the trade-off, not the marketing.
Firebase Auth is Google's identity layer — free to 50K MAU, tight integration with Firestore / Cloud Functions / FCM. The catch: every downstream use of the user ID (lifecycle email, audience segmentation, support inbox) leaves the Firebase ecosystem and becomes a separate vendor. Sendora ships the same auth depth (email/pass + magic link + email OTP + passkeys + MFA + 7 social + OIDC + SAML + SCIM) plus 21 other modules sharing the same `user_id`. If you're using Firebase Auth + Mailchimp + Mixpanel + Zendesk, Sendora collapses the stack.
Google's auth-as-a-service. Free to 50K MAU. Tight Firebase ecosystem integration; weak outside it.
Same modern auth surface (passkeys / MFA / SSO / SAML / SCIM) where identity is wired to your messaging + analytics + support instead of to Firestore.
Side-by-side
| Capability | Firebase Auth | Sendora |
|---|---|---|
| Email/password + magic link | ✅ | ✅ |
| Email OTP | Limited | ✅ 6-digit, 5-min TTL, 5-attempt lockout |
| Phone / SMS auth | ✅ load-bearing for many apps | ❌ — explicitly out of scope |
| Passkeys / WebAuthn | Limited (third-party libs) | ✅ native on web + iOS + Android |
| TOTP MFA + recovery codes | ✅ | ✅ |
| Social providers | ✅ 10+ via FirebaseUI | ✅ 7 (Google / GitHub / Apple / MS / LinkedIn / FB / Discord) |
| SAML / OIDC SSO | ✅ via Google Identity Platform (paid) | ✅ Business+ |
| SCIM 2.0 provisioning | Limited | ✅ Business+, Users + Groups |
| Bulk hash import (bcrypt / scrypt / argon2) | ✅ | ✅ |
| Realtime DB / Firestore | ✅ (Google's killer feature) | ❌ — explicitly out of scope |
| App Check (anti-bot) | ✅ | Partial — Turnstile-equivalent on widget submissions |
| Lifecycle messaging + audiences in same tenant | ❌ — pair with Mailchimp / Customer.io | ✅ Automation + Email + Push + SMS + Audiences |
| Pricing | Free → 50K MAU + extras priced per-feature | Bundled — event-based tiers |
Why teams switch to Sendora
- If you're using Firebase Auth + Mailchimp + Mixpanel + Zendesk + OneSignal + AppsFlyer, Sendora collapses 6+ vendors into 1.
- Passkeys ship natively on web + iOS + Android; Firebase passkey support is third-party.
- Auth events feed Automation workflows in real time — no Cloud Function glue layer.
When Firebase Auth is the right call
- You're using Firestore / Cloud Functions / Firebase Hosting deeply — staying in the ecosystem dominates.
- You need phone / SMS auth — Sendora explicitly doesn't ship this.
- Your app needs realtime database — Sendora is event-based, not realtime-doc-sync.
- Free 50K MAU is hard to beat as a standalone auth choice for early-stage apps.
Common questions
Does Sendora replace the Firebase ecosystem (Auth + Firestore + Functions + FCM)?
Only the Auth + FCM parts. Sendora's Push module ships APNs + FCM + Web Push natively. Firestore (realtime DB) + Cloud Functions are NOT in scope — keep them if your app depends on them.
Phone / SMS auth — when is Sendora shipping?
Not on the near-term roadmap. We ship 6-digit email OTP instead. If phone auth is load-bearing for your app (Gojek / DoorDash style flows), Firebase remains the better choice today.
App Check equivalent?
Partial. The Contact Widget submission endpoint ships a signed-token + honeypot challenge (replaces Turnstile). General-purpose App Check across every endpoint is not built; the API-key layer is the gate.
Authentication
Identity that's already wired to your product — not a black-box you bolt CRM plugins onto.
Auth0 gives you logins. Clerk gives you logins. Sendora gives you logins that already know what the user did in your app, what they consented to, which experiment they're in, which audience they belong to, and how to message them across every channel — because identity, events, profiles, messaging, and support all share one tenant. Auth0 + Mixpanel + Customer.io + Zendesk + Intercom in one bill, one SDK, one user_id.
Switch from Firebase Auth. Keep your weekend.
Free plan covers real product use, no credit card. Bulk hash import for auth, CSV import for profiles, schema-validated event import for analytics — Data Sync module handles the migration in a day.