Environment Variable
An Environment Variable is a named setting outside application code. It lets each environment use different values.
Another example
One container image reads different database hosts and base URLs in preview and production without changing code.
Main parts
- 01Identity or input
- 02Policy or transformation
- 03Stored result and audit evidence
Use it when
Use it for deploy-time settings and approved secret references supplied by the runtime.
Do not use it when
Never expose secrets in client bundles, logs, screenshots, or committed .env files. Use clear names.
Name used in code
process.env / runtime secret injection 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 Environment Variable for this system while keeping data correct, secure, and easy to operate. User context: One container image reads different database hosts and base URLs in preview and production without changing code. Technical concept or control: Environment Variable. Why it fits: Use it for deploy-time settings and approved secret references supplied by the runtime. Do not use it when: Never expose secrets in client bundles, logs, screenshots, or committed .env files. Use clear names. 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 Environment Variable. Definition: An Environment Variable is a named setting outside application code. It lets each environment use different values. 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.