Realtime where it earns it
Live listeners so two devices see the same state at the same moment, and plain reads everywhere else.
Cloud & infrastructure
Infrastructure decisions are the ones that are expensive to reverse. Where the data lives, who is allowed to write to it, and what happens when a request fails halfway — we settle those deliberately, and we measure rather than assume.
What this includes
Money handled server-side
Balances and settlement computed by the backend. A client can display a number; it never gets to decide one.
Access rules that actually deny
Security rules written against a threat model and tested against it, not left permissive with a comment.
Deployments you can reason about
Region choices made by measurement, environments that match, and a pipeline that refuses a deploy it cannot verify.
Typically built with
FirebaseCloud FunctionsFirestoreSecurity RulesNode.jsTypeScriptCI/CD
How it runs
- 01Model
Data shapes, access patterns, and where money and state are allowed to move.
- 02Build
Functions, rules and listeners, with tests around anything that charges.
- 03Prove
Failure testing — dropped connections, retries, partial writes, region checks.
- 04Operate
Monitoring, alerting, and a runbook for the day something does go wrong.