Supabase vs Firebase vs PlanetScale: Backend Comparison

Supabase, Firebase, and PlanetScale represent three distinct approaches to backend infrastructure. Supabase is a PostgreSQL-based platform offering database, authentication, storage, edge functions, and real-time subscriptions. Firebase is Google's NoSQL platform built around Firestore (document database) with authentication, hosting, cloud functions, and real-time sync. PlanetScale is a serverless MySQL platform focused on database branching and horizontal scaling.

The database choice is the fundamental differentiator. Supabase gives you PostgreSQL — the most powerful open-source relational database with full SQL, joins, transactions, and extensions like PostGIS for geospatial data. Firebase gives you Firestore — a NoSQL document database optimised for real-time sync and mobile development. PlanetScale gives you MySQL (powered by Vitess) — designed for horizontal scaling with database branching for schema management.

As of 2026, Supabase has emerged as the most popular choice for web application development, with over 1 million databases created. Firebase remains dominant for mobile applications and Google Cloud-centric teams. PlanetScale serves teams that need MySQL specifically or require its branching workflow for database schema management.

Supabase's PostgreSQL provides the most powerful query capabilities. Complex joins, window functions, CTEs, full-text search, JSON operations, and stored procedures are all available. PostgreSQL extensions like pgvector (for AI embeddings), PostGIS (for geospatial queries), and pg_cron (for scheduled tasks) extend functionality significantly. Row Level Security policies enforce access control at the database level, eliminating entire categories of authorisation bugs.

Firebase's Firestore is a document database where data is stored as collections of JSON-like documents. Queries are fast but limited — no joins, limited aggregation, and composite queries require pre-built indexes. Firestore excels at hierarchical data structures and real-time sync, where every client automatically receives updates when data changes. The trade-off is that complex data relationships require denormalisation, which increases storage costs and complicates updates.

PlanetScale's MySQL (via Vitess) provides standard SQL with the added capability of database branching — you can create a branch of your schema, make changes, and merge them back, similar to git for database schemas. This workflow is excellent for teams managing frequent schema migrations. PlanetScale does not support foreign key constraints at the database level (they are enforced at the application level), which is a notable limitation for some data models.

Supabase Auth provides email/password, magic links, phone OTP, and social login providers (Google, GitHub, Apple, and more). It integrates directly with Row Level Security, so database access rules reference the authenticated user automatically. The auth system is well-documented and handles common patterns like email verification, password reset, and session management out of the box.

Firebase Authentication is mature and comprehensive. It supports all common providers plus anonymous authentication (useful for onboarding flows), multi-factor authentication, and identity platform features for enterprise use. Firebase Auth integrates with Firestore security rules, similar to Supabase's Row Level Security integration. For mobile applications, Firebase Auth's SDKs are particularly well-polished.

PlanetScale does not include authentication. It is purely a database platform. You must implement authentication using a separate service — Auth0, Clerk, NextAuth.js, or similar. This is a significant difference from Supabase and Firebase, which provide integrated auth. For teams that already have an authentication solution, this is not a limitation. For teams starting from scratch, the lack of integrated auth means additional setup time and another service to manage.

Firebase's real-time capabilities are its strongest feature. Firestore automatically syncs data across all connected clients in real-time. When one user updates a document, every other user viewing that document sees the change instantly — no polling, no WebSocket configuration, no additional infrastructure. This is built into the core SDK and works identically on web, iOS, and Android. Offline support is also built-in — clients cache data locally and sync when connectivity returns.

Supabase provides real-time subscriptions through PostgreSQL's logical replication. You can subscribe to changes on specific tables or rows and receive updates via WebSocket. The real-time system works well for most use cases, but it is less deeply integrated than Firebase's — you configure subscriptions explicitly rather than getting automatic sync on every query. Supabase's real-time has improved significantly and handles most application needs.

PlanetScale does not include real-time features. You would need to implement change data capture (CDC) or polling if your application requires real-time updates. For applications that primarily serve data through API requests rather than live updates, this is not a limitation.

Supabase's free tier includes 500MB database storage, 1GB file storage, 2GB bandwidth, and 50,000 monthly active users for auth. The Pro plan at $25 per month per project provides 8GB database storage, 100GB bandwidth, and higher limits across all features. Pricing is transparent and predictable.

Firebase's Spark (free) plan includes 1GB Firestore storage, 10GB per month of network egress, and 50K daily reads. The Blaze (pay-as-you-go) plan charges per operation — reads, writes, storage, and bandwidth. Costs can be unpredictable for applications with variable traffic. A moderately active application might cost $25-100 per month, but viral traffic spikes can produce unexpectedly large bills.

PlanetScale's free tier was discontinued in 2024. The Scaler plan starts at $39 per month for 10GB storage and 1 billion row reads. The cost structure is usage-based beyond the included allocation. For teams that specifically need MySQL, PlanetScale's pricing is reasonable, but Supabase offers more features at a lower starting price.

For most new projects, Supabase offers the best value — the most generous free tier, predictable paid pricing, and the broadest feature set included in the base price.

Firebase was designed for mobile development and it shows. The iOS, Android, and Flutter SDKs are polished, well-documented, and handle offline sync, push notifications, analytics, and crash reporting. Firebase's integration with Google Cloud services makes it the natural backend for Android applications. If your primary platform is mobile, Firebase's mobile-first SDK quality is difficult to match.

Supabase's strength is web development, particularly with React, Next.js, and modern JavaScript frameworks. The supabase-js client library is excellent, and integrations with tools like Lovable, Vercel, and Remix are first-class. Supabase's mobile SDKs (Swift, Kotlin, Flutter) have improved but remain less mature than Firebase's long-established mobile libraries.

PlanetScale is platform-agnostic — it provides a MySQL database with standard connection protocols. You use whatever ORM or database client your framework supports. This flexibility means PlanetScale works equally well for web and mobile backends, but you get no platform-specific SDKs or features. The developer experience is a standard database connection, not a tailored platform experience.

For most new web applications in 2026, Supabase is the recommended choice. PostgreSQL's power, combined with integrated auth, storage, edge functions, and real-time subscriptions, provides a complete backend at a competitive price. The developer experience is excellent, the free tier is generous, and the SQL foundation means your database skills transfer to any future platform.

Choose Firebase if you are building a mobile-first application (especially for Android/iOS), need Firebase's offline-first real-time sync capabilities, or are deeply integrated with Google Cloud. Firebase's mobile SDKs and real-time document sync remain unmatched for mobile development patterns.

Choose PlanetScale if you specifically need MySQL (for compatibility with existing systems or team expertise), need database branching for schema management workflows, or require the horizontal scaling that Vitess provides. PlanetScale is a focused database tool rather than a complete backend platform.

Many teams start with Supabase for its breadth of features and migrate specific workloads to specialised platforms only when they hit limitations at scale. This pragmatic approach avoids premature optimisation while keeping options open.