Firebase vs PostHog
Google's mobile & web app development platform
vs. Open source product analytics — all-in-one dev tool
Pricing tiers
Firebase
Spark (No-cost)
Free tier with generous quotas. No credit card required. Cannot exceed free quotas.
Free
Blaze (Pay as you go)
Usage-based billing. Includes Spark quotas free, then pay Google Cloud rates. Required for Cloud Functions outbound networking, scheduled jobs, some extensions.
Custom
PostHog
Free (generous)
No credit card. Each product has its own free monthly quota. Great for startups + OSS.
Free
Paid (usage-based)
Pay only what you use, after free quotas. Volume discounts at higher tiers. 6 projects, 7-year retention.
$0 base (usage-based)
Self-Hosted (OSS)
MIT-licensed. Run on your own infra via Docker/k8s. Zero vendor lock-in.
$0 base (usage-based)
Enterprise
Custom. SAML SSO, dedicated CSM, custom SLA.
Custom
Free-tier quotas head-to-head
Comparing spark on Firebase vs free on PostHog.
| Metric | Firebase | PostHog |
|---|---|---|
| auth mau | 50000 users/month | — |
| data warehouse rows | — | 1000000 rows/month |
| error tracking exceptions | — | 100000 exceptions/month |
| feature flags requests | — | 1000000 requests/month |
| firestore deletes per day | 20000 docs/day | — |
| firestore egress gib month | 10 GiB/month | — |
| firestore reads per day | 50000 docs/day | — |
| firestore storage gib | 1 GiB | — |
| firestore writes per day | 20000 docs/day | — |
| functions cpu seconds | 200000 CPU-sec/month | — |
| functions gb seconds | 400000 GB-sec/month | — |
| functions invocations | 2000000 invocations/mo | — |
| functions outbound gb | 5 GB/month | — |
| hosting storage gb | 10 GB | — |
| hosting transfer gb month | 10.8 GB/month | — |
| llm analytics events | — | 100000 events/month |
| logs gb | — | 50 GB/month |
| phone sms verifications day | 10 sms/day | — |
| product analytics events | — | 1000000 events/month |
| projects | — | 1 projects |
| retention years | — | 1 year |
| rtdb connections | 100 connections | — |
| rtdb downloaded gb month | 10 GB/month | — |
| rtdb stored gb | 1 GB | — |
| session replay recordings | — | 5000 recordings/month |
| storage downloaded gb day | 1 GB/day | — |
| storage gb | 5 GB | — |
| storage operations day | 50000 ops/day | — |
| surveys responses | — | 1500 responses/month |
| team members | — | unlimited members |
Features
Firebase · 20 features
- A/B Testing — Experiments on Remote Config params, FCM notifications, and Analytics events. Ba…
- App Check — Attestation service: only requests from authentic, untampered app instances reac…
- App Hosting — Managed hosting for modern web apps (Next.js, Angular, SvelteKit). Git-based dep…
- Cloud Firestore — Serverless NoSQL document database. Real-time sync, ACID transactions, offline p…
- Cloud Functions — Serverless functions (Node.js/Python). Trigger on HTTP, Firestore, RTDB, Auth, S…
- Cloud Storage — Object storage for user files. Built on GCS. Security rules + signed URLs. Resum…
- Crashlytics — Real-time crash reporting for iOS/Android/Unity/Flutter. Stack traces, breadcrum…
- Data Connect — GraphQL API backed by Cloud SQL for PostgreSQL. Type-safe SDK generation. Previe…
- Dynamic Links — Deep links that survive app install. NOTE: deprecated, shutdown Aug 2025 — migra…
- FCM Topics — Publish/subscribe messaging: devices subscribe to topic names; backend sends one…
- Firebase AI Logic — Client-side SDK to call Gemini models directly from mobile/web. Formerly "Vertex…
- Firebase Authentication — Drop-in auth: email/password, phone, anonymous, 10+ federated providers, custom …
- Firebase Cloud Messaging — Push notifications for iOS, Android, Web (APNs/FCM transports). Topics, device g…
- Firebase Extensions — Pre-packaged Cloud Functions + config: Stripe, Algolia search, image resize, tra…
- Firebase Hosting — Static + dynamic hosting with global CDN. Preview channels, atomic deploys, rewr…
- Genkit — Open-source AI app framework. Unified API for Gemini, OpenAI, Ollama; tools, RAG…
- Google Analytics for Firebase — Free unlimited event tracking with audience building. BigQuery export on Blaze. …
- Performance Monitoring — App startup, HTTP network, and custom traces. Integrates with Google Analytics e…
- Realtime Database — Low-latency JSON tree database with WebSocket sync. Best for high-frequency pres…
- Remote Config — Feature flags / parameterized config with conditional targeting (user property, …
PostHog · 14 features
- A/B Testing — Experiments with significance analysis.
- Data Pipelines — Export events to BigQuery, Snowflake, S3.
- Data Warehouse — Query external sources (Stripe, Hubspot, S3) alongside events with SQL.
- Error Tracking — Sentry-style error tracking in same platform.
- Feature Flags — Rollout flags with targeting, A/B testing, JSON payloads.
- LLM Analytics — Tracing + cost tracking for OpenAI, Anthropic, Gemini, etc.
- Logs — Centralized log ingest with free 50 GB/month.
- Product Analytics — Events, funnels, trends, retention, paths. SQL insights available.
- Revenue Tracking — Integration with Stripe for revenue + churn metrics.
- Self-Hosting — Docker/Helm. Full feature parity with cloud.
- Session Replay — Watch user sessions. Privacy controls, masked inputs, JS errors.
- SQL Query API — Run ClickHouse SQL over your events via API.
- Surveys — In-app surveys + feedback widgets.
- Workflows — Trigger emails/webhooks on events.
Developer interfaces
| Kind | Firebase | PostHog |
|---|---|---|
| CLI | Firebase CLI | — |
| SDK | Admin SDK (Go), Admin SDK (Java), Admin SDK (Node.js), Admin SDK (Python), Android SDK, Apple Platforms SDK, Flutter SDK (FlutterFire), JavaScript SDK, Unity SDK | posthog-android, posthog-flutter, posthog-go, posthog-ios (Swift), posthog-js, posthog-node, posthog-php, posthog-python, posthog-react-native, posthog-ruby |
| REST | Auth REST API, Cloud Storage REST, Firebase Management API, Firestore REST API, Realtime Database REST | PostHog REST API |
| MCP | Firebase MCP Server | PostHog MCP |
| OTHER | Firestore gRPC, Realtime Database WebSocket | Webhooks + Actions |
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