Better Env

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Type-safe environment config modules

Follow this best practice to manage environment variables in TypeScript applications with full type safety and clear server/public boundaries.

better-env exports configSchema to define typed env modules and recommends placing them in feature-level config.ts files (for example src/lib/auth/config.ts and src/lib/database/config.ts).

Learn more:

• references/config-schema.md

Validate existence of all env variables in the current environment

Run env validation early so missing or invalid values fail fast before dev, build, or deploy steps.

better-env validate --environment <name> loads .env* files with Next.js semantics, discovers src/lib/*/config.ts modules, and checks every declared variable from your configSchema modules.

If your dotenv files intentionally include keys that are not referenced by config modules, add per-env suppressions in better-env.ts:

environments.<env>.ignoreUnused: string[]

These suppress only the selected local environment during validate. Adapter defaults are merged in automatically; for Vercel, VERCEL_OIDC_TOKEN is ignored by default in development, preview, and production.

Learn more:

• references/env-validation.md

Configure runtime syncing between local files and hosted providers

Use runtime configuration to keep local dotenv targets aligned with provider environments while preserving safe defaults.

Create better-env.ts with defineBetterEnv(...) and an adapter (vercelAdapter, netlifyAdapter, railwayAdapter, or cloudflareAdapter), then define environment mappings, env-file targets, and gitignore behavior.

Learn more:

• references/config.md
• references/runtime.md

Use the CLI for day-to-day environment operations

The CLI gives a consistent workflow for initialization, sync, validation, and remote variable management, which is great for local development and CI automation.

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