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Hosting & Infrastructure

Firebase

Google's backend-as-a-service: Firestore/RTDB, auth, hosting, functions

What it does

Firebase is Google's Backend-as-a-Service (BaaS) platform. Bundles a NoSQL document database (Firestore), a real-time NoSQL database (Realtime Database), authentication (email, OAuth providers, phone), file storage (Cloud Storage), serverless functions (Cloud Functions), hosting (static site + CDN), analytics, crash reporting, remote config, and A/B testing. Popular for mobile apps and quick full-stack MVPs where you do not want to run a backend.

Free tier

Yes

Starts at

$25/mo

Setup

medium

Key features

FirestoreRealtime DatabaseAuthHostingCloud FunctionsAnalyticsCrashlytics

Integrates with

Android, iOS, React Native, Flutter

Who this fits

  • Mobile app developers (iOS/Android) needing auth, database, push notifications in one SDK
  • Solo founders and small teams shipping MVPs quickly
  • Real-time apps (chat, presence, collaborative tools) where Realtime Database or Firestore listeners fit
  • Startups on a budget (generous free tier for early stage)
  • Consumer apps needing quick OAuth (Google, Apple, Facebook sign-in)

Who it does NOT fit

  • Teams needing relational SQL databases (use Postgres via Neon, Supabase, PlanetScale)
  • Apps with complex queries or joins (Firestore's query model is limited)
  • Cost-sensitive teams at scale (Firestore reads/writes and Cloud Functions invocations get expensive)
  • Teams needing on-prem or fully open-source stack (use Supabase for a Firebase-alike with Postgres)

Pricing

- **Spark (free) plan:** Firestore 1GB storage, 50k reads/day, 20k writes/day, 20k deletes/day. Auth up to 50k monthly active. Storage 5GB, 1GB/day download. Hosting 10GB storage, 360MB/day transfer. Cloud Functions no free invocations on Spark (must upgrade to Blaze). - **Blaze (pay as you go):** Metered usage above the free tier. Firestore about $0.06 per 100k reads and $0.18 per 100k writes. Storage $0.026/GB/month. Cloud Functions $0.40 per million invocations plus compute time. - No middle tier; the jump from Spark to Blaze is on/off. - Blaze is required to make external API calls from Cloud Functions (a common surprise).

Real gotchas

  • Firestore security rules are code-in-a-config. Misconfigured rules leak your entire database publicly. Every Firestore breach story is a missing rule [source: firebase.google.com/docs/rules and multiple public incident writeups on HackerNews].
  • Firestore query model does NOT support joins, aggregations, or full-text search natively. You denormalize data or add Algolia/Meilisearch for search.
  • Egress bandwidth from Cloud Functions is billed at Google Cloud rates (~$0.12/GB), which surprises apps serving large payloads.
  • Firebase Analytics is free but sends data to Google for ad targeting (opt-out available). GDPR concerns apply.
  • Realtime Database and Firestore are different products with different pricing and query models. Choosing the wrong one for the use case is a common early mistake.

Integrations that matter

Google Cloud Platform (Firebase runs on GCP), Google Analytics 4, BigQuery (Firestore export for analytics), Slack (Cloud Functions triggers), Stripe (via Cloud Functions), SendGrid, Twilio, all major OAuth providers, iOS and Android SDKs, JavaScript SDK, Flutter, Unity, Genkit (Google's GenAI framework).

Otto’s take on this tool

Recommend Firebase for mobile app builders, real-time apps, and MVP teams that want auth + database + storage in one SDK without running a backend. Recommend Supabase when the client wants the same benefits but on Postgres with SQL and open-source. Recommend traditional Postgres (Neon, PlanetScale, AWS RDS) when the client needs relational modeling. Warn about scaling costs on Blaze for high-traffic apps.

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