Manage Backend Configuration

Manage Backend Configuration

Purpose

Make backend services reliable across environments by centralizing configuration, validating it at startup, and preventing secret leakage.

When to use

Use this skill when you are:

• Adding a new config parameter
• Debugging environment-specific bugs
• Introducing new integrations (databases, queues, third-party APIs)
• Refactoring scattered process.env usage into a typed config module

Inputs

• Required config values and their intended defaults
• Which values are secrets (tokens, passwords, private keys)
• Environment matrix (dev/test/staging/prod) and overrides

Outputs

• A typed config module
• Startup validation and fail-fast behavior
• A documented config contract (required, optional, defaults)

Rules

• Configuration MUST be centralized and typed.
• Configuration SHOULD be validated at startup.
• Secrets MUST NOT be logged and MUST NOT be checked into version control.
• Defaults SHOULD be explicit and environment-specific overrides SHOULD be documented.

Steps

1. Enumerate required settings (include type, required/optional, default).
2. Implement schema validation and parsing.
3. Expose a stable config object to the rest of the codebase.
4. Ensure failure is immediate when required config is missing/invalid.
5. Add a small verification:
   • “fails fast” when missing
   • “loads” with a valid example

Verification

• Config module loads successfully with valid environment variables
• Application fails fast (at startup) when a required config is missing
• Application fails fast when a config value has an invalid type/format
• Secrets are not printed in logs or error messages
• Config contract documentation is up to date with the code

Boundaries

• MUST NOT log or print secrets (tokens, passwords, private keys)
• MUST NOT commit secrets to version control (use .env.example with placeholders)
• MUST NOT access process.env directly outside the config module
• SHOULD NOT add optional config without explicit defaults
• SHOULD NOT change config schema without updating the config contract documentation

Included assets

• Templates: ./templates/ includes a typed config module and schema validation.
• Examples: ./examples/ includes a sample config contract and redaction guidance.