Backend
A backend is the server-side part behind an interface. It applies business rules, works with data, and connects other systems.
Another example
At checkout, the backend checks stock, charges the payment, and saves the order result.
Main parts
- 01Originating request
- 02Resolution or processing hop
- 03Response, timing, and failure
Use it when
Put trusted rules, shared data, integrations, and work needing a server on the backend.
Do not use it when
Never trust client-side checks alone for security or money.
Name used in code
server runtime Before you ship
Check contracts and invariants, authorization, and input limits. Test retries, one-time effects, timeouts, and partial failures. Verify data integrity, compatibility, monitoring, recovery, and rollback.
Outcome: Design or review Backend for this system while keeping data correct, secure, and easy to operate. User context: At checkout, the backend checks stock, charges the payment, and saves the order result. Technical concept or control: Backend. Why it fits: Put trusted rules, shared data, integrations, and work needing a server on the backend. Do not use it when: Never trust client-side checks alone for security or money. Engineering requirements: Define inputs, outputs, contracts, and rules that must always hold. Set authorization and input checks. Define failures, timeouts, retries, one-time effects, data moves, and compatibility limits. Operations: Add useful signals and logs that hide sensitive data. Set capacity limits and write an operator guide. Test recovery and rollback. Acceptance criteria: Contract and failure-path tests pass. Data and authorization rules still hold during retries and partial failures. Check performance limits, monitoring, recovery, and rollback. Evidence and limits (evidence boundary): No single official standard controls the whole term. Its meaning may change across teams, platforms, or frameworks. Unknowns to confirm: Where the code runs, data stores, traffic shape, consistency needs, and the security boundary. Also confirm the compatibility period, service goals, and rollback limits.
Check this request
Review the current use of Backend. Definition: A backend is the server-side part behind an interface. It applies business rules, works with data, and connects other systems. Release checks: Check contracts and invariants, authorization, and input limits. Test retries, one-time effects, timeouts, and partial failures. Verify data integrity, compatibility, monitoring, recovery, and rollback. Before changing code, report the evidence you found, gaps, severity, and the smallest safe fix.