Input Validation
Input validation checks data as it crosses a trust boundary. It enforces the expected type, shape, range, size, and meaning.
Another example
A crafted request may skip the form. The server still rejects an unknown role value.
Main parts
- 01Identity or input
- 02Policy or transformation
- 03Stored result and audit evidence
Use it when
Use allowlists and schemas at every boundary where outside data enters.
Do not use it when
Never rely only on client-side checks or a list of known bad strings.
Name used in code
schema.parse(input) 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 Input Validation for this system while keeping data correct, secure, and easy to operate. User context: A crafted request may skip the form. The server still rejects an unknown role value. Technical concept or control: Input Validation. Why it fits: Use allowlists and schemas at every boundary where outside data enters. Do not use it when: Never rely only on client-side checks or a list of known bad strings. 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 Input Validation. Definition: Input validation checks data as it crosses a trust boundary. It enforces the expected type, shape, range, size, and meaning. 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.