Every developer has been there: your code passes all local tests, you deploy to staging or production, and the application immediately crashes with KeyError: DATABASE_URL or an undefined environment variable. As projects grow, maintaining . env files across different environments becomes painful: .
Source: [Dev.to](https://dev.to/umut_gngr_57b4b16aba65950/stop-breaking-production-how-to-audit-and-sync-env-files-with-envdoctor-fmp)