Supabase vs Firebase: Which Backend Should You Use in 2026?

Short answer: pick Supabase if your data is relational (users, orders, invoices, anything with joins) or you want to connect your own backend to an AI app builder like Lovable, which can link to a Supabase project you own. Pick Firebase if you are building a mobile app that needs offline sync and real-time document updates, or your team already lives in Google Cloud. Both have usable free tiers, but they bill in very different ways, so the cheaper one depends on how your app reads data.

The core difference: a Postgres database or a document database

Supabase gives every project a full PostgreSQL database. You get tables, foreign keys, joins and SQL, plus authentication, file storage, Edge Functions and real-time on top. Access control is written as row-level security policies in the database itself. Supabase is open source and can be self-hosted.

Firebase's main database, Cloud Firestore, is a NoSQL document store: collections of JSON-like documents that you read by path and query, with security rules that sit in front of it. Firebase also has the older Realtime Database, and in 2026 it offers a relational option, Firebase SQL Connect (formerly Data Connect), which runs a managed PostgreSQL database on Google's Cloud SQL and generates GraphQL endpoints and typed SDKs from your schema.

If you think in tables and want to ask your data questions in SQL, Supabase fits. If your app is mostly "load this user's documents and keep them in sync on the phone", Firestore fits.

Supabase vs Firebase at a glance

Figures are from supabase.com/pricing and firebase.google.com/pricing in November 2026.

Pricing: how each one bills

Supabase charges a flat monthly plan and then metered usage. Pro starts at $25 a month and includes 100,000 monthly active users, 8 GB of database per project, 250 GB of egress, 100 GB of file storage and 2 million Edge Function invocations, plus $10 a month of compute credit that covers one Micro instance. Over those amounts you pay per unit, for example $0.00325 per extra monthly active user and $0.125 per extra GB of database. A spend cap is on by default on Pro. With it on, usage past a quota is blocked until the next billing cycle instead of billed. Compute, custom domains and some other add-ons are not covered by the cap. Team starts at $599 a month and adds SSO, SOC 2 compliance, 14-day backups and 28-day log retention.

The main limit on the Free plan for a live product is that Supabase pauses free projects after a week of inactivity. Paid projects are never paused, and paid plans include daily backups (7 days on Pro).

Firebase has no monthly fee. The Spark plan is no-cost and needs no payment method. Blaze is pay as you go: you keep the same no-cost quotas and pay Google Cloud rates for anything above them. Firestore's no-cost quota is counted per day (50,000 document reads, 20,000 writes, 20,000 deletes and 1 GiB stored), so cost depends on how many documents your screens read. A feed that loads 50 documents per view uses up the daily free reads faster than one that loads five.

Some Firebase features need Blaze even at small scale. Cloud Functions are Blaze only, SMS verification codes for phone sign-in are Blaze only, and a SQL Connect Postgres instance is a three-month trial on Spark, after which it is archived unless you upgrade.

The practical difference: Supabase costs are easier to predict, because you pay a known plan fee and the database is sized in GB. Firebase can cost nothing for a long time, but the bill tracks reads and writes, so a busy app with chatty screens can cost more than you expect. Set a budget alert in Google Cloud on day one.

Building with AI app builders

Lovable has its own built-in backend, enabled by default, which uses Supabase's open-source foundation. You can also connect a Supabase project you own, and Lovable then designs the tables, runs migrations and adds sign-up and login with Supabase Auth. Either way, check that every table has row-level security policies before you go live, because the browser talks to the database with a publishable key anyone can read. Lovable runs security checks for missing policies, but its docs tell you to verify them yourself in the Supabase dashboard. Our Supabase review covers what that setup gives you, and our Lovable review covers the builder side.

Firebase pairs naturally with Google's own tools, including Firebase Studio (no-cost for three workspaces) and Gemini in Firebase, and with native mobile development on Android and iOS.

When to choose Supabase

• Your data has relationships: customers and orders, teams and members, projects and tasks.
• You want to query with SQL, export to other tools, or hand the database to an analyst later.
• You want to connect Lovable or another AI builder to a Supabase project you own.
• You want a predictable monthly bill with a spend cap.
• You may want to self-host one day or keep the option open.

When to choose Firebase

• You are building a mobile app where offline use and live sync between devices matter.
• Your data is naturally document shaped, such as chat messages, user profiles or activity feeds.
• You want a no-cost start with no payment method on file.
• Your team already runs on Google Cloud.

Trade-offs to weigh before you pick

Moving later is real work in both directions. A Firestore data model does not map one to one onto Postgres tables, and Supabase's policies do not translate into Firebase rules. Pick based on your data shape now, not on which free tier looks bigger.

Free-tier limits behave differently. Supabase limits size and pauses idle projects. Firebase limits daily operations and blocks some features until you add billing. A side project you check once a month is better on Firebase's free plan; a product with daily users but a small database is fine on Supabase Free until you need backups.

Security is your job on both. Supabase relies on row-level security policies, Firebase on security rules. Neither protects your data if you leave them open, and AI builders do not always set them correctly.

Frequently asked questions

Is Supabase cheaper than Firebase? It depends on usage. Supabase Pro is $25 a month with large included quotas, which is cheap and predictable for most early products. Firebase can cost nothing on Spark and stays cheap on Blaze for low-traffic apps, but read-heavy apps pay per document read beyond 50,000 a day.

Is Supabase a Firebase alternative? Yes. Supabase is open source and covers the same jobs as Firebase: database, auth, storage, server functions and real-time. It also publishes guides for migrating from Firebase Auth, Storage and Firestore. The difference is the database underneath: Postgres instead of a document store.

Does Firebase have a SQL database now? Yes. Firebase SQL Connect, formerly Data Connect, runs a managed PostgreSQL database on Cloud SQL and generates GraphQL endpoints and typed SDKs. On the Spark plan it is a three-month trial; ongoing use needs Blaze, with Cloud SQL pricing starting as low as $9.37 a month according to Firebase's pricing page.

Which is better for a no-code or AI-built app? For web apps built with Lovable, Supabase is the closer fit: Lovable's built-in backend runs on Supabase's open-source foundation, and you can also connect your own Supabase project. For a native mobile app built with Google's tools, Firebase is the more natural fit.