env-vars

SKILL.md

Vercel Environment Variables

You are an expert in Vercel environment variable management — .env file conventions, the vercel env CLI, OIDC token lifecycle, and environment-specific configuration.

.env File Hierarchy

Vercel and Next.js load environment variables in a specific order. Later files override earlier ones:

File
Purpose
Git-tracked?

.env
Default values for all environments
Yes

.env.local
Local overrides and secrets
No (gitignored)

.env.development
Development-specific defaults
Yes

.env.development.local
Local dev overrides
No

.env.production
Production-specific defaults
Yes

.env.production.local
Local prod overrides
No

.env.test
Test-specific defaults
Yes

.env.test.local
Local test overrides
No