Supabase vs Firebase: Which Backend, and When to Outgrow Both

For a first version of an app, Supabase and Firebase will both get you to launch quickly, and the better pick depends on the shape of your data. Supabase vs Firebase comes down to one difference. Supabase gives you a full Postgres database, so your data lives in related tables you can query with SQL. Firebase’s Firestore stores documents in collections, which is quick to start with and gets awkward when you need reports or relations.

This guide is for a founder or product owner choosing a backend for an MVP or a SaaS product. It covers what a backend-as-a-service gives you, how each one bills, where the data can live in the UK, how security goes wrong, and what lock-in looks like. It also says when a custom backend is the better answer, because we have shipped products on Firebase, run our own product on Supabase and build most client backends in Django, and we will tell you which fits. Our MVP development work usually starts with this decision.

Key takeaways

• Supabase is Postgres under a friendly layer, so relational data, SQL reporting and a route out are easier. Firestore is a document database, quick to start and harder to report on.
• Both bill on usage in dollars. Supabase Pro is from $25 a month, and Firebase’s Blaze plan charges for document reads and writes, so model your real usage first.
• Both list a London region, but Firebase says the default location cannot be changed, so decide before you create the project.
• Most data leaks from either one come from loose access rules, so treat Row Level Security and Security Rules as part of the build, not a finishing touch.
• A custom Django and PostgreSQL backend wins once you have real business logic, an admin team, multi-tenant customers or enterprise single sign-on.

What does a backend-as-a-service give you?

A backend-as-a-service (BaaS) gives you the parts every app needs without building them: sign-in, a database, file storage and somewhere to run small pieces of server code. You connect your app to it and spend the budget on the product instead.

Supabase and Firebase both cover those four jobs. Firebase is Google’s, and its pricing page lists Authentication, Firestore and Cloud Functions as separate products on the same plan. Supabase bundles Auth, Storage, Realtime and Edge Functions around one database, and describes that database as “a full Postgres database, not a Postgres abstraction”.

For a first version, that is a real saving. Our MVP development page says we have shipped lean first versions on Firebase, with auth, data and hosting handled so the budget goes on the product. The trade-off arrives later, when the product’s rules outgrow what the service does for you.

What is the real difference between Supabase and Firebase?

The real difference is the database. Supabase is Postgres, a relational database where data sits in tables with defined links between them. Firebase’s Cloud Firestore is a NoSQL document database, where information is stored as documents grouped into collections.

Here is what that means in practice. An app with users, teams, projects and invoices is relational by nature. In Postgres, “all invoices for a team’s projects this quarter” is one query. In a document store you either copy data into several places or run several reads and join the results in code, and each read is billed.

Firestore is a good fit when your data is naturally one document per thing: a user profile, a chat message, a settings record.

Firebase now has a relational option too. Its Firebase SQL Connect page describes a relational database service for mobile and web apps, running on a fully managed PostgreSQL database powered by Cloud SQL. If you are drawn to the Firebase ecosystem but want SQL, look at that before ruling Firebase out.

How do Supabase and Firebase pricing compare?

Both are cheap to start and hard to predict at scale, because both bill on usage. At the time of writing (November 2026), the figures below come from each vendor’s official pricing page, and both show dollars rather than pounds.

Supabase (pricing page):

• Free: 50,000 monthly active users and a 500 MB database, and free projects are paused after one week of inactivity.
• Pro: from $25 a month, with 100,000 monthly active users, then $0.00325 per extra user, and an 8 GB disk per project, then $0.125 per GB.
• Team: from $599 a month.

Firebase (pricing page):

• Spark: no-cost, no payment method needed, and limited to fixed quotas. Its Firestore quota is 50,000 reads and 20,000 writes a day, and Authentication includes 50,000 monthly active users.
• Blaze: pay as you go with no fixed base price. Cloud Functions, for example, are not available on Spark, so a real product ends up on Blaze.

The two models behave differently. Supabase’s bill follows a plan plus the disk, compute, egress and user counts you use, which is easier to forecast. Firestore charges for documents read and written, including a minimum of one read for every query, even one that returns nothing. A screen that lists 50 items is 50 reads each time it loads.

Neither is a reason to avoid it. It means you should sketch your busiest screens, count the reads and writes, and price them before you commit. A cost surprise on Firestore usually traces back to a chatty design, not to the service.

Where can your data live in the UK?

Both offer London. Supabase’s region list includes “West Europe (London), eu-west-2”, and Firestore’s location table lists europe-west2 as London. Our own ChatQuote product runs on Supabase (Postgres and authentication) hosted in London.

Choose carefully, because Firebase’s locations page says the location for default Google Cloud resources “is an immutable setting”. Pick London when you create the project, not after your first customers arrive.

A London region keeps stored data in the UK. It does not settle every data protection question, because processors, support access and sub-processors also matter. Check the vendor’s data processing terms for your own case. This is general information, not legal advice.

How does security go wrong on each?

Security goes wrong on both when the access rules are too loose, and it is the classic way a BaaS app leaks data. Your app talks to the database from the browser or phone, so the rules on the database are the only thing standing between a user and everyone else’s records.

On Supabase, those rules are Postgres Row Level Security. Supabase’s guidance says to enable RLS on every table in an exposed schema, and warns never to use a secret key in the browser or expose it to customers. A table without a policy is the usual mistake.

On Firebase, the rules are Security Rules written in their own language. Firebase’s own documentation warns never to use the open ruleset in production, because it allows anyone to overwrite the entire database. “Test mode” rules that get left on are a familiar story.

Both fail the same way: someone ships the quick version and forgets to tighten it. The fix is to write and test the access rules before the first real user, including a test that tries to read another user’s data and expects to be refused. For enterprise buyers, plan for the next level too. Supabase lists SAML single sign-on on plans Pro and above, billed per SSO user on top. We design single sign-on, roles and audit trails in from the start in our enterprise work, because retrofitting them is slow.

How locked in are you, and can you leave?

Supabase is easier to leave. Your data is in Postgres, so you can dump it and run it anywhere Postgres runs, and Supabase documents self-hosting with Docker. It describes self-hosting as community-supported and lists Postgres maintenance as your responsibility, so leaving still costs engineering time.

Firebase is harder to leave. Your data is in Firestore documents, your rules are in Firebase’s rule language, and your sign-in and functions use Firebase’s SDKs. Moving means reshaping the data and rewriting the glue.

Neither lock-in is a scandal. It is a cost you take on in exchange for speed, and the honest question is whether you will still be happy with it in year three. We say when a client has outgrown Firebase. That is part of how we run managed cloud work for products we have shipped, where we host and monitor Firebase backends month to month.

When is a custom backend the better choice?

A custom backend is the better choice when the product has real business logic that a database and a few rules cannot express. That means pricing rules, approval workflows, background jobs, integrations with other systems, an admin interface for your team, or reports that join many tables.

Here is how the options compare for a typical buyer.

Option	Good fit	Watch for
Supabase	Relational data, SQL reporting, a smaller team	Access rules, compute sizing
Firebase	Simple mobile apps, fast first launch	Read costs, reshaping data later
Custom Django backend	Real logic, admin, multi-tenant SaaS	Higher upfront cost

Most of our client backends are Django and PostgreSQL on AWS. Bonsai’s wealth-planning app, Baandy’s home-swap app and the Go Quest city treasure-hunt platform all run on that stack. PostgreSQL is the database our own platforms are built on, and Django is our usual choice where an application has real logic behind it.

Firebase appears in cases we have shipped too. Cicerone’s outdoor guide app and the Dooit services marketplace list Firebase alongside a Django and PostgreSQL backend, and the wholesale supply chain startup lists it as a service. So Firebase and Django often sit side by side in our work.

Where does the rest of the field fit?

• FastAPI for a single, high-throughput service. We have built high-throughput services with FastAPI where a full Django app would be overkill.
• Node.js where your team already writes JavaScript. We work in Node.js, though our longest production miles are on Python.
• Next.js for the web front end. ChatQuote pairs it with Supabase and runs on Vercel.

What about multi-tenant SaaS?

Design tenancy first. In a multi-tenant product, one codebase serves every customer with hard walls between their data, and retrofitting those walls is painful.

Supabase suits this well when you write the policies so every row carries a tenant, and RLS enforces the wall in the database. ChatQuote is our own multi-tenant product, built on Supabase. In Firebase, the same wall is built from Security Rules and collection structure, which works but is easier to get wrong at scale.

With a custom Django backend, tenancy, roles and single sign-on are code you own and can test. Whichever you pick, decide the tenant model, the roles and the sign-in method in the first week, before the first customer’s data goes in.

What keeps any backend healthy?

The platform matters less than the habits around it. A backend without these habits fails the same way on Supabase, Firebase or Django.

• Deployment pipelines. Every change should build, test and deploy through a pipeline, so releases are boring.
• Monitoring and alerts. Logs, metrics and alerts in one place, so you hear about a problem before your users do.
• Backups tested by restoring. An untested backup is a hope, not a plan. Restore one on a schedule and time it.
• Environments as code. We work with Terraform for infrastructure as code, so your environments can be rebuilt from the repository, not from someone’s memory.
• Containers where they earn it. We work with Docker and Kubernetes where scale demands them, and most small and mid-sized workloads do not need Kubernetes.

For a hosted Firebase or Supabase product, much of this is the vendor’s job. For anything you run yourself, it is yours or your partner’s. We run hosting, monitoring and backups for products we have shipped, and our DevOps service covers pipelines and infrastructure as code. Our guide to cloud migration for SMEs covers moving a system that has outgrown where it lives.

What will the decision cost, and what should you do next?

For most founders the backend is a small part of the cost, and a wrong choice is the expensive part. With us, MVP validation and design starts from £5,000 in 2 to 4 weeks, and a full MVP build starts from £15,000. Both are fixed price, you own the code, and support after launch starts from £400 a month. Managed hosting starts from £900 a month, and a cloud migration from £5,000. See our guide to how much an app costs in the UK for the wider picture.

A sensible next step is a one-page backend brief. List the five things your data must answer (the reports, the permissions, the integrations), your busiest screen and its reads, your expected users after a year, and any customer demands such as UK hosting or single sign-on. If the list is short and mostly user records and files, Firebase or Supabase will do. If it includes real rules, reporting or enterprise customers, plan for Django and PostgreSQL.

Our MVP development service starts from that brief, and our guide to how to build an MVP covers what goes in the first version. If your product takes money, read our comparison of Stripe vs GoCardless next. Building across iOS and Android as well? See React Native vs Flutter.