Neon vs Supabase vs Firebase: Real Backend Cost for an AI SaaS in 2026

The short answer: these three do not bill the same thing, and the three figures below are not fully comparable to each other. Firebase meters individual database operations (reads, writes, deletes) and bandwidth directly; Supabase bundles a fixed compute instance, storage and bandwidth allowance into a flat monthly plan with overage; Neon prices raw Postgres compute by the CU-hour and storage by the gigabyte, with no bundled extras and no egress line in this article's model. For a chat/RAG SaaS profile at 100,000 monthly active users, that produces roughly $2,976 a month on Firebase, $1,847 on Supabase, and $1,102 on Neon's Postgres compute-and-storage layer alone. That Neon figure is not an all-in backend cost equivalent to Firebase's or Supabase's: it excludes authentication, object/file storage, realtime subscriptions, and network egress, all of which Neon does not bundle and all of which a real deployment would need to source and pay for separately, on top of the $1,102 shown here. None of these figures include LLM token costs, which are a separate external line for any AI feature.

What each vendor bills

Firebase (OFFICIAL, Firebase/Firestore pricing documentation). Pay-per-operation on the Blaze plan: document reads $0.06 per 100,000 (50,000 free daily), writes $0.18 per 100,000 (20,000 free daily), deletes $0.02 per 100,000 (20,000 free daily), storage $0.18 per GiB (1 GiB free), network egress $0.12 per GiB (10 GiB free monthly). One source cites a lower regional read rate of $0.03 per 100,000, which conflicts with the more commonly cited $0.06 figure; this article uses $0.06. Cloud Functions: 2 million invocations free monthly, then $0.40 per million, plus separate GB-second and CPU-second compute charges. Costs scale directly and continuously with usage; there is no flat monthly floor beyond the free allowances.

Supabase (OFFICIAL, Supabase pricing page). Free: $0, 50,000 MAU, 500 MB database, 5 GB egress, 1 GB storage. Pro: $25/month, 100,000 MAU, 8 GB database, 250 GB egress, 100 GB storage, 2M Edge Function invocations. Team: $599/month, same resource limits as Pro but adding SOC2/ISO27001 compliance, longer backup and log retention, and SLA support. Compute beyond the included Micro instance (2-core ARM, 1 GB RAM) is an add-on ladder from about $5/month (Small) up to $1,200/month (16XL) for dedicated instances. Egress overage is $0.09/GB beyond the plan allowance; storage overage was not consistently published at a specific per-GB rate in the sources reviewed (an illustrative $0.021/GB is used below, flagged as an estimate). Edge Function overage is $2 per million invocations.

Neon (OFFICIAL, Neon documentation, post-2025 Databricks acquisition). Raw Postgres, no bundled auth, storage-object, or realtime layer. Compute: $0.106 per CU-hour, autoscaling up to 16 CU (about 64 GB RAM), with scale-to-zero available so idle projects consume no compute. Storage: $0.35 per GB-month, a price that dropped sharply after Databricks acquired Neon in 2025 (REPORTED). The Launch plan has no fixed monthly minimum beyond usage; 100 projects are included with idle projects consuming no compute. Neon does not include authentication, file storage, or realtime subscriptions; those must be sourced separately (Clerk, Auth0, S3, or similar), which is direct engineering and vendor cost this article's totals do not capture.

Three app profiles

All ILLUSTRATIVE, expressed as usage per monthly active user: A: lightweight CRUD AI app — 5 reads and 2 writes a day, 5 MB of stored data per user, 50 MB of monthly egress per user. B: chat/RAG SaaS — 30 reads and 10 writes a day (conversation history, retrieved context), 30 MB stored per user, 200 MB of monthly egress per user. C: high-write collaborative AI app — 100 reads and 60 writes a day (realtime collaboration, frequent small updates), 15 MB stored per user, 150 MB of monthly egress per user.

Backend cost by MAU and profile

Formula: Firebase = (reads over free × $0.06/100k) + (writes over free × $0.18/100k) + (storage over 1 GiB × $0.18) + (egress over 10 GiB × $0.12); Supabase = plan fee + compute add-on + storage overage + egress overage; Neon = compute (CU × 720 hours × $0.106) + storage (GB × $0.35), sizing compute to an ILLUSTRATIVE CU tier per MAU band (0.25 CU under 10,000 MAU, 1 CU up to 100,000, 4 CU at 1,000,000, always-on).

Profile B: chat/RAG SaaS

Profile A: lightweight CRUD

Profile C: high-write collaborative

Backend cost per MAU

Formula: cost per 1,000 MAU = monthly cost ÷ MAU × 1,000. On profile B at 100,000 MAU: $29.76 per 1,000 MAU on Firebase, $18.47 on Supabase, $11.02 on Neon. At 1,000 MAU, Firebase's pure pay-per-operation model actually undercuts both bundled-plan competitors on the lightweight profile ($5.36 versus $25.00 and $20.79), because Firebase has no plan floor and this profile's usage stays well within the free daily allowances; Supabase's and Neon's costs at this scale are dominated by their respective plan minimum and always-on compute assumption rather than actual usage.

The fixed plan floor versus the pay-per-operation floor

Supabase's $25/month Pro plan is a real, vendor-imposed floor: small applications pay it regardless of how little they use. Neon has no equivalent vendor-imposed minimum; Neon itself supports scale-to-zero, so a genuinely idle or low-traffic project can pay close to nothing in compute. The floor shown for Neon in this article's tables comes from this article's own ILLUSTRATIVE modeling choice to keep compute always-on (0.25 CU running continuously) rather than let it scale to zero between requests, which better represents a continuously-used production app but is a modeling assumption, not a Neon pricing rule. Firebase has no floor of any kind: an application that stays within the free daily quotas pays nothing. This crossover point is why Firebase can be the cheapest option at very low usage and the most expensive at high usage within the same profile — its costs scale linearly with operations from zero, with no volume discount, while Supabase's plan fee and this article's always-on Neon assumption are both amortized over more usage as MAU grows.

Database and compute crossover

Formula: the point at which a fixed-plan platform becomes cheaper than a pay-per-operation platform. On profile B, Supabase becomes cheaper than Firebase somewhere between 1,000 and 10,000 MAU (at 1,000, Firebase is cheaper; at 10,000, Supabase is cheaper), because Firebase's operation costs grow faster than Supabase's plan-based costs once daily free quotas are exceeded by a meaningful margin.

Egress sensitivity

Bandwidth is the line that separates these three most sharply at scale. Formula: egress cost contribution = egress GB × per-GB rate. At 100,000 MAU on profile B (19,531 GB of monthly egress in this model), Firebase's $0.12/GB egress rate (after a small free allowance) contributes roughly $2,340 to its total bill, while Supabase's bundled 250 GB allowance covers a tiny fraction of that volume, pushing the rest into its $0.09/GB overage rate — a lower per-GB rate than Firebase's, which is a real reason Supabase beats Firebase at scale on bandwidth-heavy profiles. Neon's advantage over Firebase in this article's tables is not evidence of the same effect: Neon's model here has no egress line at all, because network transfer for a raw Postgres database is priced by whichever cloud or network path sits in front of it, not by Neon directly, and this article does not model or include that cost. Neon's lower total should be read as "compute and storage only, egress unpriced," not as proof that Neon's bandwidth is cheaper than Firebase's.

What is not in these numbers

LLM token costs for any AI feature (chat completions, RAG retrieval, embeddings) are entirely separate from backend hosting and are not included in any figure above; they belong on whichever model provider's own invoice. Authentication is bundled into Supabase and Firebase but not Neon, which needs a separate auth provider. Realtime subscriptions are native to Supabase and Firebase but not offered by Neon.

Sensitivity

1. Egress volume. The single largest driver of the gap between vendors at scale; a lower-bandwidth profile narrows the spread significantly.
2. Firebase read/write rate conflict. A $0.03 versus $0.06 per 100,000 reads discrepancy across sources would roughly halve Firebase's read-cost line if the lower rate is correct.
3. Neon compute sizing. This model's CU-tier assumptions are illustrative; actual compute needs depend on query complexity and concurrency, not MAU count alone.
4. Supabase storage overage rate. Not consistently published; the $0.021/GB figure used here is an estimate, not a confirmed vendor rate.

Budgeting traps

• Comparing a bundled plan price to a pay-per-operation rate without modeling your own usage. The cheaper platform flips depending on MAU and profile.
• Ignoring the always-on compute assumption on Neon. Scale-to-zero eliminates this cost for genuinely idle projects, but a continuously-used production app does not benefit from it.
• Forgetting that Neon has no bundled auth, storage, or realtime. Add the cost of those separate services before comparing its total to Supabase's or Firebase's all-in price.
• Treating LLM token cost as part of the backend bill. It is not; budget it separately against whichever model provider you use.

What to ask before you buy

Model your own reads, writes, storage growth and egress per active user from real usage data, not an assumed profile, and run all three formulas above with those numbers. Ask Supabase for its current storage overage rate in writing, and confirm Firebase's current per-100,000-read rate against the live pricing page given the conflicting figures in circulation.

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