Authentication · decision tool

Firebase Auth vs Better Auth — for your app, not in general

Firebase Auth or Better Auth? Set your usage, budget and constraints; the verdict, monthly cost and risks update live from verified pricing.

Prices verified 2026-07-15 against official pricing pages · fit weights are our estimates (see methodology) · share the URL to share your configuration

As of Jul 2026, with 5,000 monthly active users, a $50 budget for this slot, Firebase Auth ranks first for these inputs at 90% fit and a StackSays-estimated $0/month (Better Auth: 77% fit, $0/month). Fit weights are our estimates; prices trace to official pages. Change any input below and the verdict recomputes.

Your situation

The verdict updates as you move these.

Monthly active usersusers who actually sign in each month — the billing metric for most providersBudget for this slot ($/mo)what you'd accept paying for the auth provider layerTeam size1 = solo; bundled platforms save glue time for small teams

Clear pick for your inputs

Firebase Authfit 90% · est $0/mo

Google's mobile-first auth; free to 50K MAU, Google Cloud rates beyond

vs Better Auth: fit 90% against 77%, est $0 against $0 per month

Firebase Authfit 90%

$0/mo

Better Authfit 77%

$0/mo

Comparing 2 tools head-to-head. Open the full field (7 options) →

The decision, in plain words

For a solo builder at 5,000 monthly active users and a $50.00/mo budget for the auth provider slot, Firebase Auth leads at 90% fit and $0/mo. The two rules doing the work: budget fit (Runs free at your usage — $0 vs your $50/mo budget); free-tier runway (Your usage fits the free tier today (50,000 MAU at no charge)).

The gap to Better Auth (77% fit) is wide at these inputs — you'd need to change your requirements, not your taste, to flip it.

Honest weak spot of the pick: hosted user store — migrating away means a coordinated export (password hashes via support).

Generated from the calculation above — every number traces to the sourced data; nothing here is written by an AI making things up.

Why Firebase Auth scores 90%

Budget fit (weight 30, our estimate) — Runs free at your usage — $0 vs your $50/mo budget+30

Batteries included (weight 12, our estimate) — Bundles prebuilt sign-in UI — fewer services to glue at team size 1+4

Exit cost (weight 4, our estimate) — Hosted user store — migrating away means a coordinated export (password hashes via support)-1.2

Ecosystem maturity (weight 8, our estimate) — established — our estimate from ecosystem age, docs and hiring pool+8

Free-tier runway (weight 10, our estimate) — Your usage fits the free tier today (50,000 MAU at no charge)+10

Total (lines sum exactly)50.8

Possible range −64…+64 (sum of active rule weights) · fit % = (total + max) / (2 × max)(50.8 + 64) / 128 = 90%

How the $0/mo estimate is calculated

Your usage fits Firebase Auth's free tier (50,000 MAU at no charge) — the estimate is $0.

What could change this verdict

Cost risk

Estimated now (StackSays estimate, not your final bill)$0/mo · Spark (free)

Free-tier statusOn the free tier (50,000 MAU at no charge)

Next known billing thresholdSpark (free) caps at 50,000 mau — beyond that you change plans

Official prices verified 2026-07-15; calculation is deterministic code over those prices.

At a glance

Tool	Free tier	Paid entry	Verified
Better Auth	No free tier	—	2026-07-15
Firebase Auth	50,000 MAU at no charge	—	2026-07-15

Where did you land?anonymous, one click

Data sources

Tool	Source	Verified
Better Auth	Better Auth pricing page	2026-07-15
Firebase Auth	Firebase pricing page	2026-07-15

A monitor re-checks these pages for changes; when a vendor moves a price, the date updates and every verdict recomputes.

Keep deciding