Open-source backend-as-a-service (BaaS) platforms give you the core pieces Firebase provides, namely a database, authentication, file storage and realtime updates, without locking your data into a single proprietary vendor. The four main options in the Stackora catalog are Appwrite, Supabase, PocketBase and SurrealDB. They differ mainly in how they store data, how much they bundle, and how much operational work they leave to you.

How to evaluate the options

Before comparing products, decide which criteria matter for your project:

  • Data model: relational (Postgres), document, or document-graph.
  • Scope: how much is included out of the box, such as auth, storage, functions, messaging and hosting.
  • Realtime: whether clients can subscribe to data changes.
  • Deployment footprint: a single binary you can run anywhere, or a multi-service stack.
  • License: all four listed projects are open source, but the license terms differ (see below).
  • Community and maturity signals: GitHub star counts give a rough indication of adoption, though they say little about fit for your workload.

Appwrite

Appwrite is an open-source backend platform that bundles auth, databases, storage, functions, messaging and hosting in one place. Its catalog category is Databases & Storage, it is published under the BSD-3-Clause license, and it has about 57,700 GitHub stars.

Strengths

  • Broad scope: most of the typical app backend is covered by one product.
  • Permissive BSD-3-Clause license.
  • Positioned for developers and AI agents as well as traditional app teams.

Trade-offs

  • A wider feature set means more surface to learn and operate than a narrower tool.
  • Teams that specifically want a relational SQL database may prefer a Postgres-first option.

Supabase

Supabase describes itself as an open-source Postgres development platform: a Firebase-style backend with a hosted database, auth, APIs, storage and vector tools. It is in the Databases & Storage category, under Apache-2.0, and has about 111,600 GitHub stars, the highest of the four.

Strengths

  • Built on Postgres, so standard SQL, relational modelling and existing tooling apply.
  • Auto-generated APIs and auth on top of the database.
  • Includes vector tools, relevant for AI-related workloads.

Trade-offs

  • Relational schemas and SQL require more upfront design than a schemaless document store.
  • Multiple components mean a larger operational footprint if you self-host.

PocketBase

PocketBase is an open-source Go backend delivered as a single file. It provides a database backend with realtime subscriptions, user auth, file storage and an admin UI. It is under the MIT license and has about 61,400 GitHub stars.

Strengths

  • Single-binary deployment makes setup and hosting simple.
  • Realtime subscriptions, auth, file storage and an admin UI are included.
  • MIT license is short and widely understood.

Trade-offs

  • Its scope is narrower than Appwrite or Supabase; it is aimed at smaller applications and prototypes.
  • Scaling beyond a single instance is not its design centre, so plan capacity carefully for larger workloads.

SurrealDB

SurrealDB is a distributed, collaborative document-graph database built for the realtime web. It sits in the Developer Tools category, has about 33,200 GitHub stars, and its catalog entry does not list a license, so check the repository before adopting it.

Strengths

  • Combines document and graph data models in one database.
  • Explicitly designed for realtime applications and distributed deployment.

Trade-offs

  • It is a database rather than a complete BaaS, so you will need to build or integrate auth, storage and hosting yourself.
  • The missing license information in the catalog means you should verify licensing before commercial use.

Which should you pick?

  • Choose Supabase if you want a full Firebase-style backend on Postgres and expect relational data, SQL and vector features.
  • Choose Appwrite if you want the broadest bundled backend with a permissive BSD-3-Clause license.
  • Choose PocketBase if you want a small, easy-to-run backend in a single file for a prototype, internal tool or small product.
  • Choose SurrealDB if your core need is a flexible document-graph database for realtime data, and you are comfortable assembling the rest of the stack yourself.

For most teams replacing Firebase end to end, Supabase and Appwrite are the closest matches. Start with a small proof of concept against your real auth and realtime requirements before committing to one platform.

For related tooling, browse the Developer tools and Databases & Storage categories, or the Libraries & SDKs page for client libraries.