GCP and Firebase Free Tier Cost Planning

Free launch planning should not treat every zero-dollar line the same. New-customer trial credits, Firebase no-cost plan limits, and Google Cloud always-free monthly usage behave differently, so model them separately before deciding that an app is safely free.

Trial credits can hide an architecture that already has paid cost behavior. Always-free usage is limited by product, region, resource type, and monthly allowance. The safest estimate is the bill after temporary credits are gone and the app is running on normal production traffic.

For Firebase-first apps, the first paid meter is often not hosting itself. Watch Firestore reads from list screens, Storage downloads from images or user files, Cloud Functions invocations, phone authentication, BigQuery exports, and log volume.

For Cloud Run apps, estimate requests, average response time, CPU, memory, minimum instances, outbound transfer, and the database behind the service. A small Cloud Run API can still become paid quickly if it keeps an instance warm or triggers heavy Firestore, Cloud SQL, or Storage work on every request.

Before launch, create one calculator scenario for the expected first month and another for the month after promotional credits or early free capacity no longer masks usage. Use the second scenario for architecture decisions, not only the optimistic launch month.

Pair the estimate with billing budgets, service-level alerts, App Check where appropriate, cache rules for public assets, and clear limits on list screens and uploads. If the post-free-tier estimate is dominated by reads, downloads, or minimum instance hours, fix that path before buying more capacity.