PostHog vs Firebase
Open source product analytics — all-in-one dev tool
vs. Google's mobile & web app development platform
Pricing tiers
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
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
Free-tier quotas head-to-head
Comparing free on PostHog vs spark on Firebase.
| Metric | PostHog | Firebase |
|---|---|---|
| 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
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.
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, …
Developer interfaces
| Kind | PostHog | Firebase |
|---|---|---|
| CLI | — | Firebase CLI |
| SDK | posthog-android, posthog-flutter, posthog-go, posthog-ios (Swift), posthog-js, posthog-node, posthog-php, posthog-python, posthog-react-native, posthog-ruby | 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 |
| REST | PostHog REST API | Auth REST API, Cloud Storage REST, Firebase Management API, Firestore REST API, Realtime Database REST |
| MCP | PostHog MCP | Firebase MCP Server |
| OTHER | Webhooks + Actions | Firestore gRPC, Realtime Database WebSocket |
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