Firebase vs Supabase: Which Backend Saves Startups Money
Firebase bills you $1,847 in month six for an app that costs $43 on Supabase. Same features, same user count, wildly different economics.
January 8, 2025 11 min read
Firebase bills you $1,847 in month six for an app that costs $43 on Supabase. Same features, same user count, wildly different economics.
The pricing gap widens as you grow. Firebase's model punishes success - every read, every user, every megabyte adds cost. Supabase charges flat rates that stay predictable as you scale.
Both backends promise to eliminate server management and accelerate development. Only one does it without surprise billing.
The Pricing Reality
Firebase uses pay-per-use pricing. Supabase uses tiered subscription pricing. This single difference drives thousands of dollars in cost variance.
Firebase Pricing Breakdown
Firebase's free Spark plan is genuinely free but unusable for production:
50,000 document reads per day
20,000 writes per day
1 GB storage
10 GB network egress per month
That is roughly 100-200 active users if your app is read-heavy. Hit the limit mid-day and your app stops working until midnight UTC.
The Blaze plan (pay-as-you-go) charges:
Firestore: $0.06 per 100,000 reads, $0.18 per 100,000 writes
Storage: $0.026 per GB stored, $0.12 per GB downloaded
Authentication: $0.06 per verification (SMS), email is free
Cloud Functions: $0.40 per million invocations plus compute time
Hosting: $0.15 per GB transferred
Reads accumulate fast. A dashboard that shows a feed of 20 items? That is 20 document reads per page load. User refreshes 10 times per day? 200 reads per user daily. 1,000 users means 200,000 reads per day, or 6 million per month.
Stop planning and start building. We turn your idea into a production-ready product in 6-8 weeks.
6 million reads at $0.06 per 100,000 = $360/month just for feed reads.
Add writes, storage, functions, and hosting. A modestly active app hits $500-2,000 monthly by month three to six.
Supabase Pricing Breakdown
Supabase offers transparent tiers:
Free tier:
500 MB database space
1 GB file storage
2 GB bandwidth
50,000 monthly active users
Unlimited API requests
Production apps outgrow this quickly, but it handles development and early beta testing.
Pro tier ($25/month):
8 GB database space
100 GB file storage
250 GB bandwidth
100,000 monthly active users
Unlimited API requests
7-day point-in-time recovery
This tier handles most startups through Series A. We have clients with 40,000 users running on Pro without issues.
Team tier ($599/month):
Same features as Pro
Multiple projects
1-hour point-in-time recovery
Better SLAs
The Enterprise tier adds dedicated support, SOC 2, HIPAA compliance, and custom contracts.
The critical difference: Supabase charges based on database size and bandwidth, not request count. Your read-heavy dashboard costs the same as a write-heavy collaboration tool - zero marginal cost per request.
Cloud Functions: $40-100 (estimated for auth, triggers, API)
Total: $608-668/month
Supabase Pro cost:
All operations included: $0
Storage within limits: $0
Bandwidth within limits: $0
Total: $25/month
The cost difference is $583-643 monthly, or $7,000-7,700 annually. For the exact same functionality.
Scale to 20,000 users and Firebase easily hits $2,000-3,000 monthly. Supabase Pro still works until you exceed bandwidth limits, then you might pay overages or upgrade to Team tier.
Feature Comparison
Both platforms provide auth, database, storage, and real-time subscriptions. The implementations differ.
Database and Queries
Firebase Firestore:
NoSQL document database
Collections and documents structure
Limited query capabilities (no joins, complex filters restricted)
Denormalization required for complex data
Real-time listeners built in
Supabase Postgres:
Full PostgreSQL database
Relational tables with foreign keys
Complete SQL support including joins, aggregations, window functions
Views, triggers, and stored procedures available
Real-time subscriptions via PostgREST
If you know SQL, Supabase is faster to build with. If you prefer NoSQL thinking, Firebase feels more natural. But SQL is objectively more powerful for complex data relationships.
Both provide email/password, OAuth (Google, GitHub, etc.), and magic links. Implementation quality differs.
Firebase Auth:
Works seamlessly with Firestore security rules
Built-in email verification and password reset
Session management handled automatically
Mobile SDKs are mature and stable
Supabase Auth:
Built on GoTrue, an open-source auth system
Row-level security policies tied to auth
Email verification and password reset included
Supports passwordless magic links natively
Firebase Auth is more mature with better mobile SDK support. Supabase Auth has caught up significantly and adds features like email OTP and phone auth without per-use charges.
For most use cases, both work fine. Firebase charges $0.06 per SMS verification. Supabase includes SMS in paid tiers with quota limits (currently 50-100 per month on Pro, purchase more as needed).
Real-Time Data
Firebase Firestore real-time:
Native real-time listeners on documents and queries
Client-side listeners update automatically
Offline support with local cache
Charged per document read when listener receives update
Supabase real-time:
PostgreSQL logical replication via Realtime server
Subscribe to database changes (inserts, updates, deletes)
Subscribe to presence and broadcast channels
No per-operation charges
Both work well for dashboards, chat apps, and collaborative features. Firebase's offline support is more polished. Supabase's real-time does not increase costs when subscribers are active.
Storage
Firebase Storage:
Built on Google Cloud Storage
Integrated security rules
Resumable uploads
CDN distribution included
Charges: $0.026/GB stored, $0.12/GB downloaded
Supabase Storage:
Built on AWS S3
Row-level security policies
Resumable uploads
CDN via built-in integration
Included in tier limits (100 GB on Pro)
Supabase includes 100 GB storage on Pro tier. Firebase charges per GB from byte one. For media-heavy apps, this is hundreds of dollars monthly difference.
Serverless Functions
Firebase Cloud Functions:
JavaScript/TypeScript on Node.js
Integrates with Firebase services
Triggered by Firestore changes, HTTP, schedules
Cold starts can be 1-3 seconds
Pricing: $0.40 per million invocations plus compute time
Supabase Edge Functions:
TypeScript/JavaScript on Deno runtime
Deployed globally via Deno Deploy
HTTP triggered, can call from database
Faster cold starts (~50-200ms)
Included in paid tiers (500k invocations on Pro)
Firebase Functions are more mature with better local emulation. Supabase Edge Functions are faster and included in subscription pricing.
For background jobs and webhooks, both work. Supabase does not surprise you with function invocation bills.
Developer Experience
Firebase has a decade head start. The ecosystem is massive - every question has Stack Overflow answers, every edge case has blog posts.
Supabase launched in 2020. The community is smaller but growing fast. Documentation is excellent, often clearer than Firebase's sprawling docs.
Firebase strengths:
Mobile SDKs are rock solid (iOS, Android, Flutter)
Local emulator suite for offline development
Mature libraries for every framework
Extensive third-party integrations
Supabase strengths:
All features accessible via standard PostgreSQL
Direct database access for debugging and admin tasks
Auto-generated REST and GraphQL APIs
Open source (self-hostable if needed)
Firebase locks you into Google's platform. Supabase lets you export your database and migrate if needed. This optionality matters for some founders.
When Firebase Makes Sense
Firebase is not always the wrong choice. It wins in specific scenarios:
Mobile-first apps with low data access patterns: If your app is primarily mobile, offline-first, and users access small amounts of data infrequently, Firebase's offline support and mobile SDKs are unmatched.
Prototypes that might not launch: If you are testing an idea quickly and might abandon it, Firebase's generous free tier (within limits) costs nothing. Supabase requires payment after development phase.
Google Cloud ecosystem commitment: If you are all-in on Google Cloud (using Cloud Run, GKE, BigQuery), Firebase integrates seamlessly with those services.
Team familiar with NoSQL: If your team knows Firestore patterns and is productive with it, switching to SQL adds learning curve overhead.
But for most startups building SaaS products, these scenarios are edge cases.
When Supabase Wins
Supabase is the better default choice for most web applications and SaaS products:
Predictable costs matter: If surprise bills would hurt your runway, Supabase's flat pricing is worth it.
Read-heavy applications: Dashboards, analytics tools, content platforms. Firebase punishes reads. Supabase does not care.
Complex data relationships: If your data model has many-to-many relationships, nested structures, or requires complex queries, Postgres is vastly superior to Firestore.
SQL familiarity: Most developers know SQL. Learning Firestore's query model takes time and limits power users.
Team wants code ownership: Supabase is open source. You can self-host if needed. Firebase is proprietary and lock-in is permanent.
Migrating from Firebase to Supabase (or vice versa) is painful. Plan for weeks of work.
Firebase to Supabase:
Export Firestore data to JSON via scripts
Transform document structure to relational tables
Rewrite all queries from Firestore syntax to SQL
Rebuild security rules as Postgres row-level security
Update client code to use Supabase client libraries
Expect 40-80 hours of engineering time for a moderately complex app.
Supabase to Firebase:
Export Postgres tables to JSON
Denormalize relational data into document collections
Rewrite SQL queries to Firestore queries (often impossible directly)
Rebuild row-level security as Firestore rules
Update client code to Firebase SDKs
Similar timeline, often harder because SQL queries do not map cleanly to Firestore's limited querying.
The migration tax is high. Choose correctly the first time.
The Lock-In Question
Firebase is vendor lock-in. Google owns the platform, controls pricing, and has shut down products before (see: Google Reader, Inbox, etc.). You cannot easily migrate off Firebase without a complete rewrite.
Supabase is open source. You can self-host on AWS, Render, or your own servers if pricing becomes untenable or the company pivots. The data lives in PostgreSQL - industry standard with 30+ years of stability.
For founders worried about platform risk, Supabase's open nature provides an exit path. Firebase does not.
Performance Considerations
Both platforms are fast when used correctly. Both can be slow if used poorly.
Firebase pitfalls:
Over-fetching data in queries (no limit/offset leads to downloading entire collections)
Security rules that scan large collections
Deeply nested documents causing large payloads
Lack of indexing on filtered fields
Supabase pitfalls:
Missing database indexes on frequently queried columns
N+1 query problems without proper joins
Unoptimized Postgres queries scanning full tables
Not using connection pooling (Supavisor handles this)
Properly optimized, both handle thousands of concurrent users. Poorly implemented, both fall over at hundreds.
The difference: Postgres gives you profiling tools (EXPLAIN ANALYZE), indexes, and decades of optimization knowledge. Firestore's optimization is more opaque.
Compliance and Security
Both platforms offer enterprise security features on higher tiers.
Firebase:
SOC 2, SOC 3, ISO 27001 certified (via Google Cloud)
GDPR compliant with data residency options
HIPAA available with Google Cloud healthcare API and BAAs
No self-hosting option
Supabase:
SOC 2 Type II certified
GDPR compliant with EU region options
HIPAA compliance on Enterprise tier with BAAs
Self-hosting available for maximum control
For most startups, both meet compliance needs. Healthtech and fintech might prefer Supabase's self-hosting option or Convex's HIPAA and SOC 2 certifications.
The Verdict for Most Startups
Choose Supabase unless you have specific reasons for Firebase.
Supabase wins on:
Predictable, flat pricing
SQL power and flexibility
Open source portability
Read-heavy workload economics
Firebase wins on:
Mobile offline support
Ecosystem maturity
Google Cloud integration
NoSQL familiarity
For a typical Next.js SaaS application with web and mobile clients, Supabase saves $5,000-10,000 in year one and avoids billing anxiety.
The TCO (total cost of ownership) gap widens every month as usage grows. We have moved all new projects to either Supabase or Convex depending on requirements. Firebase is reserved for rare cases where offline-first mobile is non-negotiable.
Key Takeaways
Backend choice affects your runway, product velocity, and long-term costs:
Lock-in risk: Firebase locks you in permanently. Supabase is open source and portable.
Cost at scale: $25-600/month (Supabase) vs $500-3,000/month (Firebase) for similar workloads.
Start with Supabase for web apps and SaaS products. Consider Firebase only if you need exceptional mobile offline support or are committed to Google Cloud.
The decision saves or costs you thousands of dollars. Choose wisely.
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