Supabase vs Azure SQL free tier — what to host your side project on

The two are not competing for the same slot. One hands you a whole backend in an afternoon; the other hands you a proper SQL Server database that lives where the rest of the Microsoft stack lives. The question is which friction you're trying to remove.

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Supabase and Azure SQL's free tiers solve different problems. Supabase is an instant Postgres backend-as-a-service — database, auth, file storage, and auto-generated APIs in one free project, ideal for zero-config prototyping. Azure SQL's free offering is a managed SQL Server-family database aimed at .NET and Microsoft-stack work. Pick Supabase for speed to your first endpoint; pick Azure SQL if you're already in Azure.

I get asked this a lot by people building their first real thing on the side — a full-stack app, a portfolio project, a little SaaS they might charge for one day. They frame it as a fight: Supabase or Azure SQL, which free tier wins. It isn't really a fight, and treating it as one is how people end up with the wrong tool bolted to the wrong app. Let me lay out what each one really is, then the honest part everyone skips — what happens the day you outgrow "free."

They're answering two different questions

Supabase is what people mean when they say "backend-as-a-service." You create one project and you get a managed Postgres database, plus a bundle of things you would otherwise have to wire up yourself: user authentication, file/object storage, row-level security, realtime subscriptions, and a REST and GraphQL-ish API generated straight off your tables. The pitch is speed. You can go from empty project to a working signup-and-save-data flow in an afternoon, without standing up a single server. For a solo builder or a small full-stack team, that removed friction is the whole appeal.

Azure SQL's free offering is narrower and, in a good way, more boring. It's a genuinely free Azure SQL Database — the serverless flavor — which is a managed member of the SQL Server family. You get the database engine and nothing bundled around it: no auth service, no file storage, no auto-API. It's a place to keep relational data, spoken to in T-SQL, sitting inside your Azure subscription next to whatever else you run there. If your app is .NET and Entity Framework, this is the database it was born to talk to, and it inherits Azure's identity, networking, and billing rather than introducing a second vendor.

Supabase sells you a backend. Azure SQL sells you a database. Know which one your project is short on.

The comparison, side by side

Figures below describe each provider's free offering as of 2026. Free-tier limits move constantly — treat this as the shape of the deal, not a contract, and confirm current numbers on each provider's own pricing page before you build on them.

The honest part: what breaks when you outgrow free

A free tier is a convenience for prototyping, not a foundation for a business. Both of these will carry a hobby project comfortably. Both have a specific edge where "free" stops being free, and it's better to meet those edges on paper than in production.

Supabase: the pause. On the free plan, a project that sees no activity for a run of days gets paused. It doesn't vanish — you restore it from the dashboard — but the first request after a quiet week can fail or hang while the project wakes up. For something you demo occasionally, that's fine. For anything a stranger might hit at a random hour, it's a bad first impression. The free plan also caps you at a couple of active projects and a small database size, so a second and third experiment eat into the same allowance. The fix is the Pro plan, which removes the pausing — and that's a real monthly bill, not a rounding error.

Azure SQL: the allowance. The free Azure SQL Database gives you a fixed monthly ration of serverless compute plus a data cap. A quiet prototype never comes close. But an app that gets steady traffic, or one that keeps the database busy, can spend the monthly compute allowance before the month is out — at which point you either wait for the reset or move to a paid tier. The serverless model also auto-pauses the database when idle, so an occasional request pays a cold-start delay while it resumes. Predictable once you know it; surprising if you don't.

How I'd choose

Strip it down to what your project is short on today.

• You want a working backend this weekend. Supabase. If you'd otherwise be hand-rolling auth, an API layer, and file uploads on top of a bare database, the bundle is the point. You get to spend your evenings on the app, not the plumbing.
• Your app is .NET, or you're already in Azure. Azure SQL. One identity model, one bill, one set of tooling. Entity Framework talks to it natively, and you're building the muscle memory of the platform you'll likely be paid to run. That last part matters more than the free tier does.
• You specifically need Postgres on Azure. Neither headline option — reach for Azure Database for PostgreSQL and keep the engine your code already expects.
• You're learning cloud engineering, not just shipping a toy. Azure SQL, and do it the hard way once. Provision it, connect a small app, watch it auto-pause, read the cost meter. That loop teaches you how managed data services behave under a real PaaS model — the kind of understanding that shows up in interviews.

My tilt, for the reader who's here to build an Azure career rather than just park some rows somewhere: default to the Microsoft-stack tools even when Supabase is faster on day one, because the friction you fight while learning Azure is friction you're getting paid to have already fought. Supabase is a superb way to ship a prototype. Azure SQL, and the services around it, are how you learn the platform employers are hiring for. Those aren't the same goal, and the right pick depends on which one is yours this month.

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