Supabase vs Firebase for Australian Apps: Security, Data Residency and Which to Choose
Supabase and Firebase both let you ship a backend in hours. They differ on data residency, security defaults and what bites you when a vibe-coded app goes to production.
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Supabase and Firebase are the two backends that come up in almost every AI-generated app we audit. Both can wire up a database, authentication and file storage in an afternoon. Both ship with security defaults that can leave your data exposed if the AI building your app does not configure them correctly.
The choice matters more for Australian businesses than it might for a US startup. Data residency, the Privacy Act 1988, and the OAIC's Notifiable Data Breaches scheme mean the "just ship it in the cloud" default carries real compliance weight.
Quick answer
- Supabase is the better default for Australian apps: Postgres, Sydney region available, Row Level Security as the access control model, open source, and no vendor lock-in at the data layer.
- Firebase is a better fit when you need real-time sync to mobile clients, you are already deep in Google Cloud, or your team knows Firestore rules well enough to configure them correctly.
- Both ship with security gaps when an AI tool generates the integration code. RLS disabled on Supabase and open Firestore rules on Firebase are the two most common findings in our audits.
Quick comparison
| Supabase | Firebase | |
|---|---|---|
| Database | Postgres (relational, SQL) | Firestore (NoSQL, document-oriented) |
| Auth | Built-in (JWT, OAuth, magic links) | Firebase Authentication (mature, mobile-focused) |
| Storage | S3-compatible object storage | Cloud Storage for Firebase |
| Access control model | Row Level Security (Postgres policies) | Firestore Security Rules (JSON-like rules DSL) |
| Real-time | Realtime subscriptions over Postgres CDC | Firestore live listeners (native, very mature) |
| AU data residency | Sydney region available (ap-southeast-2) | Sydney region available (australia-southeast1) |
| Self-hosted | Yes (Docker, open source) | No |
| Open source | Yes (MIT / Apache) | No |
| Pricing model | Free tier, then usage-based | Spark (free), then Blaze (pay-as-you-go) |
| AI / vibe coding fit | Lovable, Bolt, most AI builders default here | Firebase Studio, some Replit templates |
| Vendor lock-in | Low (Postgres, exportable) | Moderate (Firestore data model, Google ecosystem) |
The security gap that bites vibe-coded apps
Before getting into the per-platform breakdown, the single most important thing to understand is how each platform handles access control by default, and where AI-generated code tends to leave the gap open.
On Supabase, the access control layer is Row Level Security. It is a Postgres feature that attaches policies to tables: "authenticated users can only read rows where the user_id column matches their own id." When RLS is enabled and policies are correct, a user cannot see or modify another user's data even if they send a crafted API request using the public anon key. The problem: RLS is disabled by default on new tables. Lovable and other AI builders sometimes miss this. We see apps with open tables readable by anyone with the anon key in roughly half the Supabase audits we run.
On Firebase, the equivalent is Firestore Security Rules. They default to open in the Firebase emulator ("anyone can read and write") and must be explicitly tightened before production. The same AI-generated gap exists: rules that allow public read/write because the AI shipped the emulator default or a broad rule while trying to unblock development.
Both are fixable. Neither is the platform's fault. Both are the kind of thing an independent code review catches before launch.
Supabase
Supabase wraps Postgres with an auto-generated REST API, a real-time layer, authentication and object storage, all exposed through a JavaScript client library that AI tools know well. The underlying database is plain Postgres, which means you can connect any Postgres-compatible tool, run raw SQL, and migrate off Supabase by exporting your data.
Where it shines. For Australian SMBs, the Sydney region (ap-southeast-2) is a direct answer to data residency obligations. Personal information stays in Australia, which is the cleanest path under the Privacy Act for businesses that do not want to argue about cross-border data transfers. The open-source codebase also means you can self-host if your compliance requirements go further. Supabase's alignment with Postgres means your team's SQL knowledge transfers directly and schema migrations, indexes and joins all work as expected.
Where it bites. RLS policy logic requires understanding Postgres policy syntax. AI builders often generate RLS policies that look correct but contain logic errors (matching on the wrong column, a policy that covers SELECT but not INSERT). Real-time subscriptions work, but are not as mature as Firestore's live listeners for mobile-first apps. The dashboard is excellent but Supabase's operational overhead increases if you go beyond the managed cloud to self-hosted.
Firebase
Firebase is Google's application development platform. Firestore is the primary database: a NoSQL document store with native real-time listeners and an offline mode that is best-in-class for mobile apps. Firebase Authentication covers social logins, phone auth and email/password with very little setup.
Where it shines. Mobile applications where real-time sync and offline support matter. Google's australia-southeast1 region (Sydney) is available, so data residency is achievable. If you are building a mobile app or a web app with heavy real-time requirements and your team already lives in Google Cloud, Firebase has deep integration across the stack. Firebase Studio (Google's AI app builder) targets Firebase natively.
Where it bites. Firestore's document model is less natural for relational data than Postgres. Querying across collections requires denormalisation. The security rules DSL is powerful but opaque, and the AI-generated version is often too permissive. Lock-in is real: Firestore's data model does not export cleanly to another database, and the client libraries are Firebase-specific. At scale, Blaze plan pricing (pay-as-you-go per read/write/delete) can surprise teams who did not model query patterns in advance.
Australian data residency: what actually matters
Both platforms offer a Sydney region. Selecting it is not automatic.
On Supabase, when you create a new project you pick the region. The default is likely not Sydney. You need to explicitly select ap-southeast-2. Once selected, all Postgres data, auth tokens and storage objects stay in that region.
On Firebase, the default Firestore region for a new project is often us-central1. You must set the region explicitly on project creation, and Firestore region cannot be changed after creation without recreating the database.
For Australian businesses handling personal information under the Privacy Act, the configuration step to verify is: which region was selected, and is the production project in that region. We have seen apps running in us-east for months because the developer prototyped in the default region and never changed it.
Pricing reality for Australian SMBs
Both have free tiers that are usable for prototypes and early-stage apps.
Supabase free includes 500MB database, 1GB storage and 50,000 monthly active users. The Pro plan starts around AU$30-40 per month per project and adds daily backups, more storage and priority support. Usage above the included limits is billed per unit.
Firebase Spark (free) is generous: 1GB Firestore storage, 50,000 reads per day, 20,000 writes per day. The Blaze (pay-as-you-go) tier is required once you exceed those limits. Reads at scale can add up quickly on Firestore: a feed that renders 50 documents per page consumed by 1,000 users per day is 50,000 reads per day, right at the free limit.
For an Australian SMB running a business app with a real user base, Supabase Pro's flat rate is often more predictable than Firebase Blaze's per-operation pricing.
Which to choose for an Australian build
| Situation | Choose |
|---|---|
| Relational data, need SQL, want to avoid lock-in | Supabase |
| Mobile app, need real-time sync and offline mode | Firebase |
| AI-generated app (Lovable, Bolt, most builders) | Supabase (default pairing) |
| Already on Google Cloud / Google Workspace | Firebase (ecosystem fit) |
| Data residency is a hard requirement, want self-hosted option | Supabase |
| Phone/SMS authentication is a core requirement | Firebase (more mature) |
The honest answer: for most Australian SMBs building a web app with AI tools, Supabase is the better default. Better lock-in story, cleaner data residency configuration, and the Postgres foundation means you are not backed into a proprietary query model.
For mobile-first apps and anything with deep Google Cloud integration, Firebase is the right call.
What to check before you launch on either
Regardless of platform, run these checks before real users touch real data:
- Supabase: confirm RLS is enabled on every table that holds user data. Check each policy covers SELECT, INSERT, UPDATE and DELETE separately.
- Firebase: confirm Firestore Security Rules do not contain
allow read, write: if true;orallow read, write: if request.auth != null;on sensitive collections without further scoping. - Both: confirm your anon/public credentials do not appear in server-side environment variables (they belong in the client) and that any service-role or admin credentials are never sent to the browser.
A vibe code audit covers all of this systematically, or run our free vibe scan as a first pass on a live Supabase-backed URL.