How to fix RESOURCE_EXHAUSTED: The quota for the service has been exceeded in Firebase

Navigate to the Google Cloud Console, select your Firebase project, then go to APIs & Services > Quotas. Filter by the service that failed (Firestore, Cloud Functions, Cloud Messaging, etc.). You'll see current usage and the quota limit. This tells you exactly what resource to optimize or increase.

If you're on a Spark plan, also note that quotas reset daily around midnight Pacific time. For immediate relief, you can:
1. Wait for the daily quota reset
2. Switch to a Blaze (billable) plan for higher limits
3. Optimize your usage to stay within limits

Spark (free) plan has severe quota limits. To unlock higher limits, upgrade to a Blaze plan:

1. Open Firebase Console > Project Settings > Billing
2. Click "Upgrade to Blaze plan"
3. Add a billing method
4. Confirm the upgrade

Once billing is enabled, you'll have access to much higher quotas and can request increases up to +25% (or more with advance notice). You'll only be charged for usage above the free tier thresholds, so small projects remain free.

Firestore quotas are mainly about read and write operations. Reduce your query consumption:

// BAD: Fetches all documents then filters in memory
const users = await db.collection('users').get();
const active = users.docs.filter(doc => doc.data().active === true);

// GOOD: Let Firestore filter, reducing reads
const active = await db
  .collection('users')
  .where('active', '==', true)
  .get();

// BAD: Fetches entire documents
const users = await db.collection('users').get();

// GOOD: Fetch only needed fields
const names = await db
  .collection('users')
  .select('name')
  .get();

Also add pagination limits to avoid large result sets:

const page = await db
  .collection('users')
  .limit(50) // Limit to 50 reads per query
  .get();

Cache frequently accessed data in memory or Redis to reduce read quota consumption:

import Redis from 'redis';

const redis = Redis.createClient();

async function getCachedUser(id: string) {
  // Check cache first (no quota hit)
  const cached = await redis.get(`user:${id}`);
  if (cached) return JSON.parse(cached);

  // Cache miss: fetch from Firestore (quota hit)
  const doc = await db.collection('users').doc(id).get();
  const data = doc.data();

  // Store in cache for 5 minutes
  await redis.setEx(`user:${id}`, 300, JSON.stringify(data));

  return data;
}

Caching is especially effective for user profiles, configuration data, and frequently queried collections.

If writing many documents, batch them and add delays to avoid hot-spotting:

async function batchWrite(documents: any[]) {
  const batchSize = 100;

  for (let i = 0; i < documents.length; i += batchSize) {
    const batch = db.batch();
    const slice = documents.slice(i, i + batchSize);

    slice.forEach(doc => {
      batch.set(db.collection('data').doc(), doc);
    });

    await batch.commit();

    // Add delay between batches
    await new Promise(resolve => setTimeout(resolve, 1000));
  }
}

This prevents writes to the same hot-spot from firing too fast.

Once billing is enabled, you can request quota increases:

1. Go to Google Cloud Console > APIs & Services > Quotas
2. Find the quota you want to increase (e.g., "Firestore Database Read Operations")
3. Check the quota
4. Click "Edit Quotas" at the top
5. Enter the new limit (you can request up to +25% in most cases)
6. Fill in your contact information and justification
7. Submit

For larger increases or time-sensitive requests (like a product launch), submit at least 30 days in advance. Google will review and approve or counter-offer within a few business days.