Best backend for an API product
Supabase, Firebase and Hasura are built for apps with a database behind them. An API product needs API-key auth and usage-based billing per call - here's what each actually gives you.
In short
The best backend for an API product isn't decided by database or auth alone - it's whether API-key auth and usage-based billing work as one system. Supabase, Firebase and Hasura give you a database or a GraphQL layer, but none bills your own downstream customers per call. That part stays DIY on every one of them.
Ask what the best backend for an API product is, and every roundup answers with the same three names: Supabase, Firebase, Hasura. All three are good backends. None of them is built for a product that is itself an API - one where a customer signs up, gets a key, and pays you by the call. That's a narrower problem than "pick a database," and it's the one this comparison actually answers.
The one-paragraph answer
If your product exposes a database or a GraphQL layer to end users through your own app, Supabase, Firebase or Hasura are still the right shortlist, and the decision comes down to SQL versus document store versus a generated GraphQL API over what you already run. If your product is the API - customers call it directly, get a key, and get billed by volume - none of the three meters or bills that for you. You wire together an auth layer for issuing keys, a counter for usage, and Stripe for the invoice yourself, on all three of them. BuildBase ships API tokens, per-call usage tracking and Stripe billing as one module, at the cost of a database you never touch directly.
What "backend" means once your product is the API
Every BaaS in this comparison was designed to sit behind an app: a mobile client, a web dashboard, something with a logged-in user clicking around. Auth in that world means a session - a cookie or a JWT that says who's currently looking at the screen.
An API product flips that. There's no screen. A customer's server calls your server, presents a key instead of a login, and does that thousands of times a month. The question isn't "who is this user" so much as "which customer issued this key, what plan are they on, and have they used their quota this cycle?" Session auth answers the first question fine. It has nothing to say about the other two.
Key takeaway
A BaaS built for logged-in users gives you session auth. An API product needs key-scoped auth tied to a plan and a running usage count - a different problem, and one that Supabase, Firebase and Hasura all leave unsolved.
Where each one fits
Supabase - Postgres, open, and DIY on the metering. Supabase vs BuildBase already covers Supabase's database, storage and auth in full; the part that matters here is the keys. Supabase issues project-level publishable and secret keys that gate a Postgres role through row-level security, plus a separate end-user JWT layer from Supabase Auth. Neither is a per-customer key you'd hand to someone paying you by the call, and nothing in Supabase counts a request against a plan or reports it to Stripe. Full SQL, extensions like pgvector, and a free tier to start on are genuine strengths - just not ones that touch billing.
Firebase - the same gap, on Google's infrastructure. Firebase Auth is built for end users signing into an app, and Blaze's pay-as-you-go pricing meters Firebase's own services against you, not your customers' usage of your API against them. If Firestore and Cloud Functions are already your stack, staying there is reasonable. Monetizing calls to your own API on top of it is a separate build either way.
Hasura - a GraphQL layer, not an auth or billing decision. Hasura doesn't authenticate anyone itself. It runs in JWT mode or webhook mode, where some other service validates the request and hands Hasura session variables to enforce permissions with. Clean separation of concerns for a GraphQL API over an existing database - and it means the auth-plus-billing question this post is about gets punted somewhere else, not answered.
An auth provider plus Stripe, wired by hand - the default everyone assembles. Most teams don't pick a single vendor for this. They add an auth provider to issue keys, a counter or a Redis key for usage, and Stripe's metered billing API for the invoice, then maintain the glue between all three for as long as the product exists. The cost of building usage metering yourself puts a number on that maintenance load, and it doesn't shrink after launch - a new plan tier touches all three systems again.
BuildBase - tokens, metering and billing as one module. API tokens are scoped to an org, named, and can be activated or revoked, and the billing module tracks usage against any metric - API calls included - tracked in real time and synced to Stripe, billing overage automatically once a plan's allowance runs out. Imejis, one of the six products running on BuildBase, is itself an API product: a template-based image generation API for marketers, built on BuildBase's user auth, API token management, billing and team collaboration - the same pieces this post is about, not a bolt-on. The trade is the one you'd expect: no direct database access, and pricing starts at $49 a month (Launch) with a 7-day trial that doesn't ask for a card - there's no free tier to build the first version against for nothing.
| Feature | BuildBase | Supabase |
|---|---|---|
| API key model | Scoped tokens, per org, named and revocable | Project-level publishable/secret keys, plus separate end-user JWTs |
| Per-call metering | Built in - any metric, tracked in real time and synced to Stripe | None - counting requests against your own customers is DIY |
| Billing your customers | Overage billed automatically once a plan allowance is used | Not provided - wire Stripe yourself against your own counter |
| Database access | None - API and SDK only | Full Postgres, SQL, extensions like pgvector |
| Pricing | $49/mo flat (Launch), published | Free tier, then usage-based |
Where Supabase wins
If your API product needs a real database underneath it rather than access through a fixed set of endpoints - vector search with pgvector for an AI product, full-text search, or just SQL you can query directly while you build
- Supabase gives you that and BuildBase does not. BuildBase's self-hosted stack runs on MongoDB, not Postgres, and even there you work through the API and SDK rather than a database console. Supabase is also open source with a real free tier, so you can build and test the whole metering-and-billing layer yourself before paying anyone. That's a genuine cost advantage early on, even though building that layer is the exact work this comparison is about avoiding.
The one honest gap
BuildBase's usage metering is per workspace plan, not per API key. Tokens are scoped to an org, not to an individual key, while usage limits and overage belong to each workspace's plan. If two of your own customers need different limits, that isn't a dial on a single key - it means putting each customer in a separate workspace, on its own plan. Worth knowing before the shape of your data model depends on it.
How to actually decide
Start with what your product actually is. If people click through screens in something you built and a database happens to sit behind it, Supabase, Firebase or Hasura are still the right shortlist - nothing above changes that. If people, or their servers, call your API directly, get a key, and pay by volume, the real question is whether key auth and billing exist as one system or three you maintain yourself. Best metered-billing tools for AI products goes deeper on the metering half alone, if billing infrastructure - not the backend around it - turns out to be the actual gap.
A note on sourcing, verified 8 September 2026. Every BuildBase figure above - the token model, the metering behavior, the $49/mo Launch price and the 7-day trial - comes from PLANS and PLAN_FACTS, plus the authentication and billing module entries in packages/shared/src/constants/. The competitor claims were read off the vendors' own pages the same day: supabase.com/pricing and Supabase's API keys guide, firebase.google.com/pricing, and Hasura's authentication docs. No competitor dollar figure appears above by choice, not by accident - all three meter something above the headline plan, so a single monthly number would be a floor rather than a price, and the shape of each model moves less often than its numbers do. Check the vendor's own page before you budget against any of them.