No Firebase Functions — Blaze requires a card on file, hard blocked
No Firebase Functions — Blaze requires a card on file
Decision
Firebase Cloud Functions are never used by any product in the family. This is a hard exclusion, not a "prefer not to" — Functions only runs on Blaze, Blaze requires a card on file, and the no-card-on-file rule is non-negotiable.
This closes the loop on firebase-spark-forever.md: Spark forever implies Functions never.
Why
- Cloud Functions for Firebase is the one Firebase service that does not run on Spark at all. There is no free quota on Spark for Functions — calling it requires Blaze enabled.
- Blaze requires a credit/debit card on file. Cloud Spend Caps are still in private preview at Cloud Next '26 and do not cover Firestore/Storage/Hosting/Functions in practice.
- Documented bill-shock cases (simmer.io ~$98K, Tamara ~$70K, €54K Gemini-key incident) all involved Blaze-tier services and confirm the catastrophic failure mode.
- Functions are not architecturally required: every workload that one would put on Functions has a card-free home elsewhere.
What replaces Functions
| Workload type | Replacement | Free-tier limit | Source |
|---|---|---|---|
| HTTPS endpoint / webhook receiver | Cloudflare Workers | 100,000 requests/day | CF Workers limits |
| Edge function on a Pages site | Cloudflare Pages Functions | Shared 100K/day with Workers | CF Pages Functions pricing |
| Scheduled cron job (>1/min granularity) | Cloudflare Workers cron triggers | Included in Workers free | CF Workers limits |
| Heavy scheduled batch (long-running, package builds, scrapers) | GitHub Actions on public repo | Unlimited minutes on public repos; 2000 min/mo on private free | GH Actions billing, GH Actions pricing 2026 |
| Per-user compute (auth-gated, requires fresh data) | Client-side fetch + Firestore REST direct from browser | Spark Firestore: 50K reads/day, 20K writes/day | firebase-rest-firestore-not-admin |
| Static-ish derived data (sitemaps, search index, OG image cache) | Build-time generation ? static JSON in Cloudflare Pages | CF Pages free unlimited static | (existing knowledge) |
| Inbound webhook reliability (retries, replay) | Hookdeck free tier ? CF Worker | per hookdeck-for-webhook-reliability |
Concrete payment-flow consequences
Payment webhooks (Razorpay, Lemon Squeezy, Polar.sh) must not be in the hot path of a CF Worker that could fail closed on quota. Concrete rule:
- Webhooks hit Hookdeck first (free tier handles retries) ? forward to GitHub Actions via
repository_dispatchfor durable processing, OR to a CF Worker that only writes to Firestore REST and returns 200 fast. - License-key fulfilment via
keygen.shis decoupled (already inmax-payment-methods.md). - A failed worker run does NOT mean a failed payment — Hookdeck retries; the customer's payment is already complete at the processor.
What changes vs prior decisions
hono-worker-api-umbrella.md: unchanged. Hono Workers were already the chosen umbrella API layer; this decision just rules out the Functions alternative explicitly.cron-split-cf-vs-gh.md: unchanged. CF Workers cron + GH Actions cron continue to split the cron load.firebase-spark-forever.md: this decision is its corollary — Functions specifically singled out as the most-tempting-to-enable trap.
Implications
- Service-catalog entries for Firebase products must show "Functions: NOT USED" in their free-tier-coverage row.
- Any prompt suggesting "deploy this as a Firebase Function" is rejected at design review.
- The
@chirag127/firebase-rest-firestorepackage handles all server-style mutations from CF Workers via the REST API — no Admin SDK, no Functions. - Any team-onboarding doc should call this out as one of the 5 things-you-cannot-do.