---

name: cost-firebase description: Estimate Firebase costs for any project using live pricing data. Use when user asks about Firebase pricing, Firestore costs, or Google BaaS costs.

Firebase Cost Evaluator

Estimate costs for Firebase-based projects using current pricing data.

Before Answering Firebase Cost Questions

IMPORTANT: Always verify tool availability before providing cost estimates.

Step 1: Check Available Tools

Check if the following tools are available:

Firebase CLI (preferred):

• firebase CLI for project information
• firebase projects:list - List projects
• firebase use - Select project

GCP Console / gcloud (for billing):

• Firebase uses GCP billing
• gcloud billing commands work for Firebase

Firebase Management API:

• REST API for project information

Step 2: If Tools Are Unavailable

If Firebase CLI is not accessible, help the user set them up:

Option A: Firebase CLI

Copy# Install Firebase CLI
npm install -g firebase-tools

# Login
firebase login

# List projects
firebase projects:list

Option B: gcloud CLI (for billing)

Copy# Firebase billing is via GCP
gcloud auth login

# Link to Firebase project's GCP project
gcloud config set project YOUR_GCP_PROJECT_ID

# View billing
gcloud billing accounts list

Option C: Firebase Management API

Copy# Get access token
# Use Firebase Admin SDK or Google OAuth

# List projects
curl -H "Authorization: Bearer YOUR_TOKEN" \
  "https://firebase.googleapis.com/v1beta1/projects"

Ask the user which option fits their environment before proceeding.

Step 3: Fallback to Web Search

If no tools are available and user cannot install them, use web search to fetch current pricing from:

• https://firebase.google.com/pricing
• https://cloud.google.com/firestore/pricing
• https://cloud.google.com/functions/pricing

How to Get Live Pricing

Using Firebase CLI

Copy# List all projects
firebase projects:list

# Get project details
firebase use YOUR_PROJECT_ID

# Open Firebase Console (for usage stats)
firebase open

Using GCP Billing (Firebase uses GCP)

Copy# Firebase billing is through GCP
# Get cost breakdown
gcloud billing accounts list

# Export billing data
bq query --use_legacy_sql=false '
  SELECT service.description, SUM(cost) as total_cost
  FROM `PROJECT.dataset.gcp_billing_export_v1_*`
  WHERE service.description LIKE "%Firebase%"
     OR service.description LIKE "%Firestore%"
     OR service.description LIKE "%Cloud Functions%"
  GROUP BY service.description'

Using Firebase Console API

Copy# Get project usage (requires Firebase Admin)
# https://console.firebase.google.com/project/PROJECT_ID/usage

# Or use the REST API
curl -H "Authorization: Bearer YOUR_TOKEN" \
  "https://firebasehosting.googleapis.com/v1beta1/projects/PROJECT_ID/sites"

Using GCP Cloud Billing API

Copy# Get SKUs for Firebase services
curl -H "Authorization: Bearer $(gcloud auth print-access-token)" \
  "https://cloudbilling.googleapis.com/v1/services"

# Firestore service ID: example lookup
# Cloud Functions: same as GCP pricing

Standalone Usage

Can be invoked directly for cost estimation:

• "How much does Firebase cost for 100k users?"
• "Estimate Firestore costs for my app"
• "What's in Firebase free tier?"

Cost Estimation Process

1. Identify plan (Spark free vs Blaze pay-as-you-go)
2. Query current pricing using available tools
3. Estimate usage based on app requirements
4. Calculate costs above free tier
5. Identify cost drivers (usually Firestore reads)

Pricing Structure (Query for Current Values)

Plans

Service Pricing (Use GCP Billing API)

Get Current Usage

Copy# Via GCP Monitoring
gcloud monitoring metrics list --filter="metric.type:firestore"

# Via Firebase Console
# https://console.firebase.google.com/project/PROJECT_ID/usage

# Firestore usage via API
curl -H "Authorization: Bearer $(gcloud auth print-access-token)" \
  "https://firestore.googleapis.com/v1/projects/PROJECT_ID/databases/(default)"

Output Contract

Copyfirebase_cost_estimate:
  description: "<what's being estimated>"
  pricing_source: "<cli|api|web|gcp-billing>"
  pricing_date: "<when pricing was fetched>"

  recommended_plan: "<spark|blaze>"

  usage_estimate:
    firestore_reads_per_day: <N>
    firestore_writes_per_day: <N>
    firestore_storage_gb: <N>
    function_invocations_per_month: <N>
    storage_gb: <N>
    bandwidth_gb: <N>
    mau: <N>

  free_tier_usage:
    firestore_reads: "<within/exceeds>"
    firestore_writes: "<within/exceeds>"
    functions: "<within/exceeds>"
    storage: "<within/exceeds>"

  baseline_monthly:
    firestore_reads: "<$X>"
    firestore_writes: "<$X>"
    firestore_storage: "<$X>"
    cloud_functions: "<$X>"
    storage: "<$X>"
    hosting: "<$X>"
    auth: "<$X>"
    total: "<$X>"

  at_10x_scale:
    firestore: "<$X>"
    functions: "<$X>"
    total: "<$X>"

  cost_drivers:
    - "<primary driver>"

  warnings:
    - "<cost warning if applicable>"

  optimization_tips:
    - "<tip 1>"
    - "<tip 2>"

Cost Optimization Strategies

Monitor Firestore Usage

Copy# Enable Firestore usage tracking
# In Firebase Console: Firestore > Usage tab

# Or via GCP Monitoring
gcloud monitoring dashboards create \
  --config-from-file=firestore-dashboard.json

Analyze Read Patterns

Copy// Enable Firestore debug logging (client-side)
firebase.firestore.setLogLevel('debug');

// Use Firebase Performance Monitoring
// Tracks Firestore operations automatically

Optimize Queries

Copy// BAD: Fetching entire collection
const snapshot = await db.collection('users').get();

// GOOD: Paginate and limit
const snapshot = await db.collection('users')
  .orderBy('createdAt')
  .limit(20)
  .get();

// GOOD: Select specific fields
const snapshot = await db.collection('users')
  .select('name', 'email')
  .get();

Use Caching

Copy// Enable offline persistence
firebase.firestore().enablePersistence()
  .catch((err) => console.log('Persistence failed:', err));

// Use cache-first queries where appropriate
const snapshot = await db.collection('config')
  .get({ source: 'cache' });

Firebase Cost Considerations

Watch out for:

• Firestore reads scale quickly (every listener = reads)
• Realtime listeners multiply read costs
• Phone auth SMS costs ($0.01-0.06 per verification)
• Large document reads (charged per document, not size)

Cost traps:

• Listening to large collections without limits
• Not using pagination
• Fetching entire documents for small fields
• Not enabling offline persistence

Firebase vs Alternatives

When comparing costs, use the respective cost evaluator skills:

• vs Supabase: Use cost-supabase for comparison
• vs AWS: Use cost-aws for comparison
• Generally: Firebase cheaper for small apps, can get expensive at scale due to read costs