Overview: Postgres vs Firestore

Supabase and Firebase are the two leading backend-as-a-service platforms in 2026. Both give you a database, authentication, file storage, serverless functions, and realtime subscriptions so you can ship apps without running servers. The core difference sits at the database layer: Supabase is built on PostgreSQL, the world's most trusted open-source relational database. Firebase uses Firestore, a proprietary NoSQL document store.

Supabase launched in 2020 and has grown fast on the premise of "an open source Firebase alternative." Firebase has been around since 2011 (acquired by Google in 2014) and has the kind of deep integration with mobile SDKs that only a decade of iteration buys.

Database

Postgres gives you SQL, foreign keys, transactions, JSON columns, full-text search, and the huge Postgres extension ecosystem (pgvector for embeddings, PostGIS for geo, pg_cron for scheduled jobs). Row-Level Security policies let you enforce auth rules at the database level, which is powerful and reduces the need for server code. Complex queries and reporting are straightforward.

Firestore is a document database with real-time subscriptions built into its data model. It scales effortlessly to enormous read volumes without schema migrations. The tradeoff is querying: Firestore has severe limits on compound queries and filtering, many things require denormalization and duplicate writes, and analytics are hard. For apps with complex relationships, Postgres wins; for apps that are mostly document reads at scale, Firestore is often simpler.

Auth & Security

Both have solid auth. Supabase Auth (powered by GoTrue) supports email, OAuth (Google, GitHub, Apple, etc.), SSO via SAML, magic links, and MFA. Combined with Postgres RLS, you get fine-grained row-level security for free. Firebase Auth supports email, OAuth, phone (SMS OTP is much stronger here), and anonymous auth, and it's deeply integrated with Firebase Security Rules. Firebase edges ahead if you need mature phone auth; Supabase edges ahead if you want SQL-enforced auth logic.

Realtime & Functions

Firestore's realtime listeners are its killer feature - a decade of production use has made them rock solid at scale. Supabase Realtime (via Postgres logical replication and WebSocket broadcast channels) has improved dramatically but still trails Firestore for apps with millions of concurrent listeners. For typical SaaS scale, both are fine.

Firebase Cloud Functions run on Google's infrastructure with Node, Python, and more. Supabase Edge Functions run on Deno Deploy globally. The Firebase platform has deeper tooling for tasks like scheduled jobs, Pub/Sub integration, and Cloud Tasks orchestration.

Pricing

Supabase free tier: 500 MB database, 1 GB file storage, 2 GB bandwidth, 50K MAU auth. Pro starts at $25/month per project with higher limits. Supabase projects pause after 7 days of inactivity on the free tier.

Firebase (Spark plan) is free up to usage limits: 1 GB Firestore storage, 50K reads/day, 20K writes/day. Beyond that, Blaze is pure pay-as-you-go. Firebase pricing can be unpredictable under heavy read volume - the "$1000 Firestore bill" horror story is real for apps that didn't cache reads carefully. Supabase's flat-fee model is easier to budget.

Vector & AI

Supabase includes pgvector natively, making it a first-class vector database for RAG and semantic search without adding another service. Firebase integrates with Vertex AI and added Vertex AI extensions for Firestore, but you typically need a separate vector DB for production AI apps.

Open Source & Lock-in

Supabase is Apache 2.0 licensed and the whole stack runs via Docker locally or on your own servers. If Supabase as a company disappeared, you'd still have a Postgres database and the open-source services. Firebase is proprietary; migrating off Firestore is notoriously painful. If portability matters to you, Supabase wins clearly.

Which One Should You Use?

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