specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: Google Firebase
providerId: google-firebase
created: '2026-05-04'
# Provenance stamped 2026-08-11: this artifact was written by the API Evangelist
# bulk sweep dated 2026-05-04, not harvested from the provider. See roadmap#35.
method: generated
modified: '2026-05-05'
reconciled: true
tags:
  - Mobile Backend
  - Serverless
  - Realtime Database
  - Google Cloud
  - Rate Limiting
description: Firebase services run on Google Cloud and inherit per-service quotas. The most actionable
  per-service limits are summarized below. Spark plan caps absolute usage at the free quota; Blaze plan
  removes the hard caps but retains per-service operational ceilings (e.g., Firestore writes-per-second
  per document, Realtime Database concurrent connections, Cloud Functions max instances). Quotas are
  raisable via the Cloud Console quotas page.
sources:
  - https://firebase.google.com/pricing
  - https://firebase.google.com/docs/firestore/quotas
  - https://firebase.google.com/docs/database/usage/limits
  - https://firebase.google.com/docs/functions/quotas
responseCodes:
  throttled: 429
  quotaExceeded: 403
  resourceExhausted: 429
limits:
  - name: Firestore writes per second per document
    scope: document
    metric: writes_per_second
    limit: 1
    timeFrame: second
    notes: Soft limit; sustained higher write rate to a single document causes contention.
  - name: Firestore writes per second per index field
    scope: index-field
    metric: writes_per_second
    limit: 500
    timeFrame: second
  - name: Realtime Database concurrent connections (Spark)
    scope: database
    metric: concurrent_connections
    limit: 100
  - name: Realtime Database concurrent connections (Blaze)
    scope: database
    metric: concurrent_connections
    limit: 200000
  - name: Realtime Database simultaneous writes
    scope: database
    metric: writes_per_second
    limit: 1000
    timeFrame: second
    notes: Approximate sustained ceiling; throughput depends on write size.
  - name: Cloud Functions max concurrent invocations (default)
    scope: function
    metric: concurrent_invocations
    limit: 1000
    notes: Default per-function concurrency; raisable via Cloud Console.
  - name: Cloud Functions outbound networking (free)
    scope: project
    metric: GB_per_month
    limit: 5
    timeFrame: month
  - name: Cloud Storage download (free Spark)
    scope: project
    metric: GB_per_day
    limit: 1
    timeFrame: day
  - name: Hosting daily data transfer (free Spark)
    scope: site
    metric: MB_per_day
    limit: 360
    timeFrame: day
  - name: Authentication monthly active users (free)
    scope: project
    metric: MAU
    limit: 50000
    timeFrame: month
    notes: Beyond 50K MAU, Identity Platform pricing applies (Auth with IdP upgrade).
  - name: Cloud Messaging (FCM) topic-message rate
    scope: app
    metric: requests_per_second
    limit: 600000
    timeFrame: minute
    notes: Per-project topic message ceiling; check current FCM docs for exact value.
policies:
  - name: Spark plan hard caps
    description: On the Spark plan, when a free quota is exhausted, the service stops responding (or returns
      quota errors) until the next reset. There is no overage; upgrade to Blaze to continue.
  - name: Blaze plan soft caps
    description: On Blaze, free quotas are deducted first; usage above is billed at GCP rates. Per-service
      operational limits (concurrency, document write rate) remain and may need quota raises for production.
  - name: Quota raises
    description: Most operational quotas (Cloud Functions concurrency, Firestore index counts, Realtime
      Database connections via sharding) can be raised through the Cloud Console quotas page on Blaze.
  - name: Backoff strategy
    description: Implement exponential backoff with jitter on 429 / 403; for Firestore, use sharded counters
      and randomized document IDs to spread write load.
  - name: Auth pricing transition
    description: Authentication transitions to Identity Platform pricing above 50K MAU; review Identity
      Platform per-MAU rates if scaling beyond the free tier.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com