It looks like just another architecture line in a technical doc. But the backend you pick today will shape your product for at least its first two years, and reversing that choice once you have real users gets expensive. For new web and mobile products, that choice almost always comes down to two names: Supabase or Firebase.
The short answer: it depends on your product's data model and which platform is your priority.
The Question That Decides Everything: Is Your Data Relational, and Is Web or Mobile Your Priority?
Before comparing features, answer two questions: does your product have entities that relate to each other (users, orders, projects, payments), or is it more like loose documents with a variable structure (posts, messages, catalogs)? And is your main platform a web app, or a native mobile app where offline support and the Google ecosystem matter?
- Relational data + a web product (or web and mobile in equal measure): Supabase usually wins, because it runs on real Postgres.
- Mobile-first app, document-style data, and you're already using Google tools: Firebase is usually the better choice because of its ecosystem and mobile maturity.
The rest of this comparison adds nuance, but this is the main fork in the road.
What Supabase Does Well
Supabase is "Postgres with superpowers," and that defines everything good about it:
- A real relational database. Standard Postgres: joins, transactions, SQL functions, extensions (pgvector for AI, PostGIS for geo). If your data model has relationships, this is a huge advantage over modeling everything as documents.
- Native Row Level Security (RLS). Row-level permissions live in the database itself, not just in application code — an extra security layer that Firestore doesn't offer in the same way.
- Auth, Storage, and Realtime built in, on top of the same database: you're not stitching together three separate systems for authentication, files, and live sync.
- Open source and portable. Because it's standard Postgres, you're not locked into a proprietary format: you can self-host or migrate to any compatible Postgres provider if you ever need to.
- Edge Functions for serverless logic, built on Deno/TypeScript.
At Cambalache Studio, we use Supabase in our own stack (Postgres, Auth, Storage, Realtime) — that gives us direct visibility into its strengths and its limits in production, though that doesn't mean it's the right answer for every product.
What Firebase Does Well
Firebase is Google's backend, and its strength lies in its ecosystem and mobile support:
- Firestore (document-based NoSQL). Scales horizontally without manual partitioning, and lets you iterate fast when your data model is flexible: catalogs with variable structure, feeds, chats — though queries that combine multiple fields require creating a composite index by hand (Firestore flags this with a link the first time you need one).
- A fully integrated ecosystem out of the box. Google Analytics, Crashlytics (error reporting), and Cloud Messaging (push notifications) come connected with no extra integration work — something you'd have to assemble with third-party tools on Supabase.
- Mobile maturity. SDKs for iOS, Android, and Flutter with years of track record, robust offline sync, and a huge community of mobile-first apps built on Firebase.
- Built-in CDN hosting for your frontend, if your stack takes advantage of it.
Firebase is hard to beat when your product is a native mobile app where offline support, product metrics, and error reporting matter from day one.
The Comparison at a Glance
| Supabase | Firebase | |
|---|---|---|
| Data model | Postgres (relational SQL) | Firestore (NoSQL, documents) |
| Complex queries / joins | Excellent | Limited |
| Auth | Yes, built in | Yes, built in |
| File storage | Yes | Yes |
| Realtime | Yes (on top of Postgres) | Yes, very mature |
| Serverless functions | Edge Functions (Deno) | Cloud Functions (Node) |
| Native analytics / crash reporting | No (third-party integrations) | Yes, out of the box |
| Mobile SDK / offline maturity | Growing | Very high |
| Open source / self-hosted | Yes | No |
| Lock-in | Low (standard Postgres) | High (proprietary format) |
How to Decide, Based on Your Case
- Web product with relational data (SaaS, marketplace, CRM, anything with users-who-have-orders-that-have-items): Supabase. It saves you from reinventing relationships that Postgres already handles well.
- Consumer mobile-first app, where you prioritize product analytics, crash reporting, and push notifications without integrating five different tools: Firebase.
- You're already in the Google ecosystem (Google Ads, Google Analytics 4, Google Cloud): Firebase reduces integration friction.
- Lock-in is a concern for you, or you want to be able to switch providers without rewriting your data model: Supabase, because underneath it's standard Postgres.
- Data with a highly variable or nested structure (documents that each take a different shape): Firestore tends to model this more naturally than forcing it into relational tables.
On Costs
Both have a free tier and a paid plan, but the pricing models are different: Supabase charges a fixed monthly plan with add-ons for extra usage, while Firebase's paid plan is pure pay-as-you-go — you pay for every read, write, and byte of bandwidth you consume. That can make Firebase cheaper at low traffic, but less predictable as usage grows.
The exact pricing for each plan changes frequently on both platforms. Any number you read here (or anywhere else) comes with an expiration date: check the current pricing and limits in Supabase's and Firebase's official documentation before deciding, especially if your product is going to see traffic spikes or a high volume of reads and writes.
Migrating Later: Possible, But Not Free
This is worth being clear on before you choose: migrating from Firestore (NoSQL) to Postgres (relational), or the other way around, isn't a config change — it's reworking how you think about your data. The more relationships your product has, the more expensive it gets if you started in NoSQL. In that sense, the backend decision is a lot like the choice between no-code and custom development: what you pick at the start to move fast carries a switching cost down the line, so it's worth deciding with the shape of your data in mind, not just which one is easier to spin up this week.
If you're still defining your product's scope before touching infrastructure, that work comes first: check out how to put together your digital product brief, or see how we approach AI-assisted development for context on where this decision fits into the rest of the project.
Where the Difference Shows Up
While your product is still a prototype, Supabase and Firebase solve the problem almost equally fast. The difference shows up later, once you have real users, your data volume grows, and the relationships between your entities get more complex — that's when the data model and platform you picked at the start begin to matter. Relational data, a web product, control, and portability → Supabase scales better. A mobile-first app, document-style data, the Google ecosystem, and offline maturity → Firebase holds up better under that growth. Neither one is the "trendy" pick in 2026: they're tools with real trade-offs, and what matters isn't which one gets you started fastest, but which one you'll still be able to run once your product isn't an MVP anymore.