Supabase vs Firebase: which backend should your MVP use?

In the Supabase vs Firebase decision, most SaaS MVPs should pick Supabase, because SaaS data (customers, teams, subscriptions, invoices) is relational and Supabase gives you a full Postgres database you can query, report on and move to another host. Pick Firebase if you're building a mobile-first consumer app with simple, document-shaped data, you want to prototype on a free plan with no payment method, or your team already works in Google Cloud.

Quick answer: Supabase is a Postgres database with sign-in, file storage and APIs built in. Its free plan includes a 500 MB database and 50,000 monthly active users, and Pro starts at $25 a month. Firebase stores data as Firestore documents, starts free on the Spark plan, then bills usage on the pay-as-you-go Blaze plan. Choose Supabase for relational SaaS data; choose Firebase for simple, mobile-first apps.

Supabase vs Firebase: side-by-side

Here's how the two compare on the points a founder actually has to decide. Prices checked October 26, 2026, on the Supabase pricing page and the Firebase pricing page. MAU means monthly active user: anyone who signs in during the month.

What's the difference between Postgres and Firestore?

Supabase is built on Postgres, a relational database: your data lives in tables (customers, projects, invoices) that link to each other, and you ask questions in SQL, the standard database query language. The Supabase repository lists the open source pieces around it, including PostgREST, which turns the database into an API, and GoTrue, which handles sign-in.

Firestore is a document database. Each record is a JSON-like document inside a collection, which works well when a screen needs one self-contained thing, like a chat message or a user profile. It gets harder when you need to combine data, such as revenue by customer by month. Reports like that usually mean copying data into several documents or stitching it together in your own code.

That shape also drives your bill. Firebase's Firestore pricing docs say you're charged for the documents and index entries read to satisfy a query, with a minimum charge of one document read per query even when nothing comes back. So a dashboard that loads 500 orders costs at least 500 reads every time someone opens it. Supabase's paid plans meter database size, egress, storage and users instead of rows read.

Is Supabase cheaper than Firebase?

At MVP scale, both are close to free. As of October 2026, Supabase's free plan covers a 500 MB database, 5 GB of egress (data sent out to your users), 1 GB of file storage, 50,000 monthly active users and 500,000 Edge Function invocations, with a limit of 2 active projects that pause after 1 week of inactivity.

Firebase's Spark plan needs no payment method and covers 1 GiB of Firestore data, 50,000 document reads, 20,000 writes and 20,000 deletes a day, plus 10 GiB of outbound data a month.

Once you have paying customers, Supabase is easier to forecast. Pro starts at $25 a month and includes 100,000 monthly active users, an 8 GB database disk per project, 250 GB of egress, 100 GB of file storage and $10 of compute credits, which covers one Micro instance. Past that, the Supabase pricing page lists $0.00325 per extra user, $0.125 per GB of database, $0.09 per GB of egress and $0.0213 per GB of storage.

Firebase's Blaze plan keeps the Spark allowances free and bills the rest at Google Cloud rates. A few published Blaze rates, as of October 2026: Cloud Functions are free up to 2 million invocations a month, then $0.40 per million, and Hosting includes 10 GB of storage and 360 MB a day of transfer, then $0.026 per GB stored and $0.15 per GB transferred. Firestore's per-read and per-write prices vary by location and sit on Google Cloud's Firestore pricing page.

Either way, your backend bill is small next to the cost of building the product. In Eltherion's software development cost calculator, a B2B SaaS MVP with two integrations built by a senior US team models at $166k to $630k of typical market pricing. That's what the wider market charges, not Eltherion's price: Eltherion projects start as low as $1,000.

How do Row Level Security and Firebase Security Rules compare?

Both products let your app talk to the database straight from the browser or phone, so your access rules are your security. Get them wrong and one customer can read another customer's data. Whichever you pick, test your rules before launch, not after.

Supabase uses Postgres Row Level Security (RLS): rules that run inside the database and act like a filter added to every query on a table. The Supabase RLS guide says to enable RLS on every table in an exposed schema, and that with RLS on and no policies, no data is reachable through the API with a publishable key. The service_role key bypasses RLS, so it must never ship in your app.

Firebase uses Security Rules, written in a separate rules file. Per the Firestore Security Rules docs, every request from the mobile and web client libraries is checked against your rules, while the server client libraries bypass them entirely. For SaaS, RLS has an edge: a policy like "users only see rows where team_id matches their team" sits next to the data and applies to every API query on that table, not just one screen.

How do Supabase Auth and Firebase Authentication compare?

Both include sign-in out of the box, priced per monthly active user. As of October 2026, Supabase Auth covers 50,000 MAUs on the free plan and 100,000 on Pro, then $0.00325 per extra user. Firebase Authentication is free up to 50,000 MAUs, then Google Cloud pricing applies.

The catch is enterprise sign-in. On the Firebase pricing page, SAML and OIDC sign-in (the single sign-on standards larger customers ask for) is free only up to 50 MAUs, and phone sign-in is billed per SMS sent. If you plan to sell to companies that require single sign-on, price that line before you commit.

Can you migrate from Firebase to Supabase later?

Yes, but plan for reshaping, not just copying. Supabase publishes a Firestore-to-Supabase migration guide with scripts that dump each Firestore collection to JSON and import it into Postgres. Each collection becomes one table, and nested data lands in basic columns or a jsonb column (JSON stored inside Postgres) unless you write code to split it into related tables.

Leaving Supabase is simpler because the core is Postgres, a standard open source database that many providers host. If you later want a different Postgres host, the trade-offs are covered in serverless Postgres vs managed Postgres. The lock-in that remains is sign-in, file storage and any Edge Functions you wrote against Supabase's own APIs.

Can you self-host Supabase?

Yes. Supabase's GitHub repository is published under the Apache-2.0 open source license, and its self-hosting guide calls Docker the fastest and recommended way to run it. The trade-offs are real: a self-hosted install runs as a single project, it's community-supported, and some platform features aren't included, such as branching, managed backups and point-in-time recovery.

You also take on servers, security, Postgres maintenance, high availability, backups and monitoring. For most MVPs, that's the wrong place to spend founder time. The value is the option: if pricing, compliance or a large customer ever requires running on your own infrastructure, the path exists.

Which is better for a SaaS MVP?

Use this checklist. If most of your answers land on one side, that's your pick.

• Pick Supabase if your data has relationships: accounts with users, projects with tasks, invoices with line items.
• Pick Supabase if you'll need reporting, exports or a business intelligence dashboard reading the same data.
• Pick Supabase if a future buyer, investor or enterprise customer may ask whether you can leave the vendor or self-host.
• Pick Supabase if you want a predictable monthly line: Pro from $25 a month with published quotas.
• Pick Firebase if you're building a mobile-first consumer app where each screen loads one self-contained record.
• Pick Firebase if your team already knows Firebase or runs on Google Cloud, and shipping this month matters more than flexibility next year.
• Pick Firebase if you want to prototype on a free plan that needs no payment method.

Pick the database that matches the shape of your data, not the one with the friendliest free tier.

Frequently asked questions

Is Supabase a good Firebase alternative?

For SaaS products, usually yes. Supabase's own repository describes building the features of Firebase using open source tools, with Postgres at the center. You get sign-in, file storage, real-time updates and auto-generated APIs, plus SQL for reporting. It's a weaker fit if your app depends on Google-specific services your team already uses.

Does Firebase offer a Postgres option?

Yes. As of October 2026, the Firebase pricing page lists SQL Connect, which runs on a Cloud SQL Postgres instance. The first default instance gets a 3-month no-cost trial, and pricing after that starts as low as $9.37 a month, depending on region and setup. If the project isn't upgraded to Blaze by the end of the trial, the instance is archived.

Is the Supabase free plan enough to launch?

It's enough to build and test, not to run a business on. Free projects pause after 1 week of inactivity and you're limited to 2 active projects. Move to Pro, from $25 a month as of October 2026, before customers depend on the app, so a quiet week never takes your product offline.

Which is more secure, Supabase or Firebase?

Both are secure when configured correctly, and both are risky when they aren't. The real danger is a missing rule: a Supabase table in an exposed schema without RLS, or Firestore rules that allow any signed-in user to read everything. Keep server keys off the client and have someone test that one account can't see another's data.

What to do next

Write down your five most important screens and the data each one shows. If the list reads like a spreadsheet with linked tabs, start with Supabase. If it reads like a stack of independent cards, Firebase will feel natural. If you'd like a second opinion, Eltherion's SaaS development services team can map your data model and choose the backend with you before any code is written.

Every project is scoped and priced up front, and Eltherion projects start as low as $1,000. Get a free estimate for your MVP, or model the build first in the free cost calculator.