Firebase Google Firebase is Google's mobile and web application development platform that helps you build, improve, and grow your app.
BaaS #database#auth#hosting
Free tier
Spark plan with generous limits
Pay-as-you-go · Multi-region
BaaS
Backend as a Service gives you auth, a database, storage and realtime APIs out of the box — so a frontend can ship a full product without a custom backend.
Backend as a Service collapses the typical backend stack — authentication, a database, file storage, access control and realtime updates — into a single managed product your frontend can call directly. For solo developers and small teams, that is transformative: you skip building login, REST endpoints and a storage layer, and spend your time on the actual product. Supabase and Firebase are the leading choices, one built on Postgres, the other on a document model.
The categories’ superpower is also its main caveat. Because the client talks to the backend directly using a public key, the access rules you write — Supabase’s Row Level Security or Firebase’s Security Rules — are what actually protect your data. Treat those policies as core application code, not an afterthought, because they are the security boundary that stands between a user and everyone else’s rows.
Free tiers here are multi-dimensional, so compare carefully. Look at database size, the number of monthly active users included for auth, file storage and bandwidth, and how much server-side logic (edge functions, triggers) you can run. Also check whether free projects pause after a period of inactivity, since that affects anything users expect to be always available. The best fit depends on whether you prefer Postgres and SQL (Supabase) or a realtime document store with deep Google integration (Firebase).
Free BaaS platforms
Firebase Google 
Supabase NEW Supabase Inc. Supabase is an open source Firebase alternative. Start your project with a Postgres database, Authentication, instant APIs, Edge Functions, and Realtime subscriptions.
BaaS #database#auth#realtime
Free tier
500MB database, 1GB storage, 2GB bandwidth
Paid from $25/mo · Multi-region
FAQ
BaaS or building my own backend?
Use a BaaS when you want to move fast and the provider's auth, database and storage cover your needs — it removes weeks of boilerplate. Build your own when you have unusual requirements, want full control of the data layer, or need to avoid vendor lock-in.
How is BaaS different from a plain database?
A database stores data; a BaaS wraps a database with authentication, file storage, access-control rules, auto-generated APIs and often realtime updates. You get a working backend, not just a place to put rows.
Is my data secure if the frontend talks to the BaaS directly?
It can be, but security depends entirely on access rules — Row Level Security in Supabase, Security Rules in Firebase. Those policies, not your client code, are the real boundary, so getting them right is essential.