Supabase vs Firebase: The Real Cost Breakdown
Data Source: Both vendors' public pricing pages, fetched live on August 29, 2026 (supabase.com/pricing, firebase.google.com/pricing). We quote what we could verify on-page today — rate cards change, so treat the arithmetic as a method, not a contract.
🚨 The Executive Verdict
Firebase meters operations. Supabase meters resources. Your app's read/write chattiness — not its size — decides which bill wins.
Supabase Pro is $25/month flat (verified today), and that $25 includes 250 GB of egress before overages start at $0.09/GB. Firebase's free tier includes 10 GiB/month of egress, then meters at $0.12/GB — and beyond the daily free quotas, every Firestore document read, write, and delete is billed per operation.
Translation: a data-heavy but quiet app (analytics dashboards, content backends) tends to be dramatically cheaper on Supabase's flat model. A chatty realtime app with millions of small reads can rack up per-operation charges on Firebase that no amount of included egress would have covered.
1. What We Verified Today (Aug 29, 2026)
| Line item | Supabase | Firebase |
|---|---|---|
| Entry paid tier | $25/mo Pro (extra projects from $10/mo) | Pay-as-you-go (Blaze), no floor |
| Included egress | 250 GB/mo in Pro, then $0.09/GB | 10 GiB/mo free, then $0.12/GB |
| Database billing unit | Compute + storage (Postgres instances) | Per document read / write / delete |
| Free-tier behavior | Projects pause after 1 week idle | Never pauses; daily quotas (50K reads/day) |
| Auth (MAU) | Included pool, then $0.00325/MAU | No-cost up to 50K MAUs |
| Compute credits | $10/mo included (covers one Micro) | Cloud Functions: $0.40/million beyond free |
Rates captured from the live pages on the audit date. Both vendors adjust pricing periodically — run your own numbers against the current cards before committing.
2. Three Spend Profiles, Honestly Modeled
Hobby / side project
Supabase: $0 — but your project pauses after a week of inactivity (verified). Cold-start friction on every return visit.
Firebase: $0 with no pausing — daily quotas reset every day. For dormant side projects, Firebase's free tier is simply nicer.
Content / dashboard SaaS
Supabase: $25/mo covers 250 GB egress + a MAU pool + a Micro of compute. Quiet read patterns rarely trigger overages.
Firebase: per-read metering means every dashboard refresh pays. Heavy-read apps feel it first here.
Chatty realtime app
Firebase: realtime listeners + small documents = per-operation volume that dwarfs data size. This is the classic bill-shock profile.
Supabase: realtime is built on Postgres logical replication — resource-metered, not per-update-metered.
3. The Cost Nobody Prices: Getting Out
Supabase is Postgres. pg_dump, standard ORMs, row-level security, any Postgres consultant on earth. Your exit cost is a database dump.
Firestore is a proprietary document model with proprietary queries and client SDKs baked into your app. Migrating off means rewriting your data layer and every listener. That is a real cost — price it in before you pick, not after.
🔮 Final Recommendation (2026)
Choose Supabase if…
- • You want Postgres portability and a real exit path
- • Traffic is read-heavy but operationally quiet
- • You prefer a flat $25 floor over per-op anxiety
Choose Firebase if…
- • It's a hobby project that must never pause
- • You live in the Google/Android ecosystem end-to-end
- • You've modeled your read/write volume and it's genuinely low
The trap in both directions: picking a backend before modeling your access pattern. Count your reads per user session first — that single number picks the winner.
Air-gapped, VPC-only, or regulated deployment? Skip the reading list.
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Take the Free Audit ←Methodology: pricing figures captured from both vendors' public pricing pages on August 29, 2026, via automated live fetch. Spend profiles are illustrative arithmetic from those published rates, not telemetry from user accounts. This review is powered by StackVerified Intelligence; we may earn a commission from links, which funds our verification infrastructure.