Best Open-Source Firebase Alternatives in 2026: Self-Hostable BaaS for Every Feature

Supabase is the most direct, full-featured Firebase replacement on the market — and the only one that lets you keep PostgreSQL's full power instead of locking you into a proprietary data model. Where Firebase gives you Firestore's document model with limited query power, Supabase hands you raw Postgres with auto-generated REST and GraphQL APIs via PostgREST, real SQL joins, transactions, and a 30-year-old battle-tested query planner.

Feature-for-feature, Supabase covers all four Firebase pillars cleanly: Auth (email/password, magic links, OAuth, phone) with row-level security policies that are dramatically more powerful than Firebase Security Rules; Realtime subscriptions over WebSockets via Postgres logical replication; Storage with S3-compatible buckets and built-in image transforms; and Edge Functions running on Deno with global low-latency deployment. The pgvector extension also gives you a production-ready vector database for free, which Firebase still doesn't have natively.

The team coming off Firebase will feel most at home here if they're willing to learn SQL — Supabase's TypeScript SDK and database studio make the transition smooth, and the managed cloud's $25/month Pro tier with a built-in spend cap means no Blaze-plan surprise bills.

Appwrite is the closest philosophical clone of Firebase in the open-source world. If Supabase is what Firebase would be if it had been built on Postgres, Appwrite is what Firebase would be if Google had open-sourced it. Same document-oriented database model, same SDK shape across 15+ languages, same one-stop-shop ambition — but every line of code is Apache 2.0 licensed and the entire platform runs on your own Docker host with one command.

For teams who like Firebase's NoSQL document model and just want to escape the vendor lock-in, Appwrite is the cleanest migration. Auth supports 30+ OAuth providers out of the box (more than Firebase). Databases are document-based with attribute schemas and indexes. Storage handles file uploads with image transformations and antivirus scanning. Functions support far more runtimes than Firebase — Node, Python, PHP, Ruby, Go, Deno, Dart, Swift, and Kotlin — all with a generous free execution budget.

Where Appwrite shines over Firebase is the developer console: it's faster, more modern, and includes built-in messaging (SMS, email, push) primitives that Firebase splits across multiple products. The trade-off is a younger ecosystem and slightly less SDK polish in non-JS languages.

PocketBase is the radical-minimalist option. The entire backend — auth, database, file storage, realtime, admin UI, REST API — ships as a single Go executable under 30MB. You download one file, run it, and you have a Firebase-equivalent backend on localhost in under 10 seconds. SQLite is embedded; there's no separate Postgres or Redis to manage.

Don't let the small footprint fool you. PocketBase covers the core Firebase use cases shockingly well: email/password and OAuth auth, realtime subscriptions over Server-Sent Events, S3-compatible file storage with built-in thumbnail generation, and a slick admin dashboard for managing collections and users. You extend it with Go or JavaScript hooks, which serve as Cloud Functions equivalents.

This is the fastest path from idea to deployed backend you'll find anywhere — and because it's a single binary with SQLite, it handles 10,000+ concurrent connections on a $5 VPS. The honest limitations: no horizontal scaling (one process, one machine), and you'll outgrow SQLite eventually if you're building a high-write-throughput SaaS. But for prototypes, internal tools, indie products, and side projects, PocketBase makes Firebase feel bloated.

Nhost is what you pick when you want Firebase's all-in-one convenience but you're a GraphQL-first team. Built on Postgres + Hasura + a custom auth and storage layer, Nhost gives you instant GraphQL APIs over your database with subscriptions for realtime — so the moment you create a table, you have a fully typed GraphQL CRUD API with realtime queries baked in.

For Firebase migrators specifically, Nhost covers all four pillars: Auth (email, magic links, OAuth, MFA, anonymous) with JWT-based session management; Database as Postgres with Hasura's instant GraphQL plus permission rules that mirror Firebase Security Rules but at the GraphQL field level; Storage with S3-backed buckets and image transforms; and Functions as Node.js serverless endpoints. The realtime story is particularly clean — GraphQL subscriptions are arguably the most elegant API for live data the industry has produced.

Where Nhost wins against Firebase is type safety: every query you write is strongly typed end-to-end via GraphQL Codegen, eliminating an entire class of runtime errors. Where it loses is choice paralysis — Hasura's permission system is powerful but takes time to master, and the Nhost cloud's pricing is less generous than Supabase's free tier.

Convex is the most different tool on this list — and the most interesting if you've felt friction with Firebase's data and realtime model. Instead of a database with a query API bolted on, Convex is built around reactive queries: you write TypeScript functions that read data, and the platform automatically re-runs them on every connected client whenever the underlying data changes. No WebSocket plumbing, no subscription cleanup, no onSnapshot callbacks. It just works.

Convex covers Firebase's pillars with a unique twist: Auth integrates with Clerk, Auth0, or custom JWT providers (no built-in user store, which is intentional); Database is a transactional document store with strong consistency; Storage is built-in for files; and Functions are first-class — every query and mutation is a function, written in TypeScript with end-to-end type safety from database to React component.

The killer feature is the developer experience. Schemas, types, and validators are defined in code and inferred all the way to your React components. Optimistic updates work out of the box. The mental shift away from Firestore's useCollection patterns is real, but most teams who make the jump don't go back. The catch: Convex isn't fully open-source — the client SDK and self-hosted edition are open, but the managed cloud is the only fully-supported deployment.

Directus is the dark-horse Firebase alternative — it started as a headless CMS but has matured into a full backend platform that competes with Supabase and Appwrite for many use cases. The key differentiator: Directus is built around the assumption that non-developers will manage the data, so the admin UI is dramatically more polished than anything Firebase or its alternatives offer.

Feature-wise, Directus checks Firebase's pillars: Auth with role-based permissions, OAuth, and 2FA; Database as a SQL layer (Postgres, MySQL, SQLite, MS SQL) with auto-generated REST and GraphQL APIs; Storage with file management and image transforms; and Flows as a visual or scripted automation engine that replaces Cloud Functions for many workflows. Realtime support arrived in v10 via WebSocket subscriptions on collections.

Directus shines specifically when your app needs both a developer-facing API and a content team manipulating the same data. Marketing, ops, or support staff get a Notion-quality admin UI; developers get instant typed APIs over the same database. For pure dev-only Firebase replacements, Supabase or PocketBase are leaner — but if your roadmap includes a non-technical team editing content, Directus wins handily.