Supabase is often called the “open source Firebase alternative.” But what powers it under the hood? The answer is simple and powerful at the same time: PostgreSQL. Not a stripped-down version. Not a lightweight copy. A full, production-grade PostgreSQL database with modern extras layered on top.
TLDR: Supabase uses PostgreSQL as its core database engine. It builds powerful tools around it, including authentication, real-time updates, storage, and APIs. PostgreSQL’s architecture allows Supabase to support extensions, scalability, and high performance. If you understand PostgreSQL, you basically understand the heart of Supabase.
Supabase Is Powered by PostgreSQL
At its core, Supabase runs on PostgreSQL, often called “Postgres.”
Postgres is an open-source, object-relational database system. It has been around since the 1980s. Yes, older than the web. And yet it is still one of the most advanced databases available.
Why?
- It is stable.
- It is battle-tested.
- It is extremely extensible.
- It handles complex queries with ease.
Supabase doesn’t reinvent the database. It embraces Postgres and enhances it.
Understanding PostgreSQL Architecture
Let’s break down how PostgreSQL works. Don’t worry. We’ll keep it simple.
PostgreSQL uses a client-server architecture.
This means:
- A server process runs continuously.
- Clients connect to the server.
- Each client query is handled in its own process.
This design makes Postgres reliable and safe. If one query crashes, the entire server does not collapse.
Key Components of PostgreSQL
- Postmaster Process – Manages connections.
- Backend Processes – Handle individual queries.
- Shared Memory – Speeds up performance.
- WAL (Write-Ahead Logging) – Ensures durability.
WAL is particularly important. Before data is written to disk, changes are logged first. This makes recovery possible if something goes wrong.
In simple terms: Postgres is built to protect your data.
How Supabase Builds on Top of PostgreSQL
Here’s where things get interesting.
Supabase does not modify Postgres into something custom and incompatible. Instead, it layers services on top of standard PostgreSQL.
These include:
- Auto-generated REST APIs
- Real-time subscriptions
- Authentication
- File storage
When you create a table in Supabase, it automatically becomes accessible through an API. That magic comes from a tool called PostgREST.
So really, when you interact with Supabase, you’re interacting with PostgreSQL through smart layers.
PostgreSQL Extensions: The Secret Weapon
This is where PostgreSQL shines. And where Supabase becomes incredibly powerful.
Postgres supports extensions. Extensions are add-ons that expand what the database can do.
Supabase takes full advantage of this.
Popular Extensions in Supabase
- pgcrypto – For encryption.
- pgjwt – For JSON Web Tokens.
- PostGIS – For geospatial queries.
- pgvector – For vector similarity search.
Yes, vector search. That means you can build AI-powered features directly inside your database.
Need location-based search? Use PostGIS.
Need embeddings for AI? Use pgvector.
Need secure authentication? Use pgcrypto and pgjwt.
It’s like turning your database into a Swiss Army knife.
Real-Time Capabilities
Databases are traditionally static. You run a query. You get results.
But Supabase adds something special: real-time updates.
How?
Through PostgreSQL’s logical replication feature.
Whenever a table changes, Supabase listens to those changes. It then broadcasts updates to connected clients using WebSockets.
So if one user updates a row, all other users see it instantly.
This is perfect for:
- Chat apps
- Collaborative tools
- Live dashboards
And the core engine behind it? Still PostgreSQL.
Performance: Is PostgreSQL Fast Enough?
Short answer: Yes.
Long answer: Very yes.
PostgreSQL is known for balancing performance with reliability.
Why PostgreSQL Performs Well
- Advanced indexing (B-tree, Hash, GIN, GiST)
- Query planner optimization
- Parallel query execution
- Connection pooling
Supabase also uses connection poolers like PgBouncer. This is important in serverless environments where connections can spike quickly.
Instead of opening thousands of direct connections, clients share a pool.
This prevents overload.
Smart architecture beats brute force.
Scalability: Can Supabase Grow With You?
Yes. And here’s how.
PostgreSQL supports:
- Vertical scaling – More CPU, more RAM.
- Read replicas – Duplicate databases for heavy reads.
- Partitioning – Splitting large tables.
Supabase manages much of this for you if you are using their hosted platform.
As your app grows:
- You can upgrade compute tiers.
- You can add replicas.
- You can optimize queries.
Since it’s standard PostgreSQL, you are never locked into a proprietary system.
Security Built on PostgreSQL
Security is another area where Supabase benefits from PostgreSQL.
One powerful feature is Row Level Security (RLS).
RLS allows you to control who can see or modify specific rows.
For example:
- User A sees only their data.
- User B sees only theirs.
This is enforced directly inside the database.
Not just in your app code.
This makes security stronger and more reliable.
Supabase heavily encourages using RLS policies. And that’s a good thing.
Structured and Semi-Structured Data
PostgreSQL is relational. That means it uses tables and structured schemas.
But it also supports JSON and JSONB columns.
This gives you flexibility.
Want strict relational data? Use tables and foreign keys.
Want flexible documents? Use JSONB.
You get the best of both worlds.
Supabase exposes this functionality directly. No hacks required.
Why Supabase Chose PostgreSQL
Let’s step back.
Why would Supabase choose PostgreSQL over building its own database?
Simple:
- It’s open source.
- It’s proven.
- It has a huge ecosystem.
- It supports extensions.
- Developers already love it.
Instead of fighting against industry standards, Supabase builds around them.
This is smart.
It means:
- No vendor lock-in.
- Easy migrations.
- Strong community support.
So What Type of Database Is Supabase?
Technically speaking, Supabase uses a relational database.
More specifically:
PostgreSQL (object-relational database system).
But in practice, it can behave like:
- A real-time database
- An API-driven backend
- An authentication provider
- A vector database for AI
All because PostgreSQL is flexible and extensible.
Final Thoughts
If you understand PostgreSQL, you understand Supabase.
Supabase is not magic. It is well-engineered infrastructure built on top of an incredibly powerful open-source database.
PostgreSQL provides:
- The storage engine
- The query processor
- The security model
- The extension framework
Supabase adds:
- Developer-friendly APIs
- Real-time features
- Authentication
- Managed hosting
Together, they create a modern backend platform that feels simple but runs on serious technology.
So next time someone asks, “What type of database does Supabase use?”
You can smile and say:
PostgreSQL. The full powerhouse version.
And now you know exactly what that means.