.env File Merger

An .env file merger combines multiple .env files into a single merged output. This is useful when merging a base .env with environment-specific overrides (.env.local, .env.production), or when consolidating environment variables from multiple microservices into a single deployment config.

When the same key appears in multiple .env files, it is flagged as a conflict. The merger shows which files define the key and what each value is. The last file wins by default (later files override earlier ones), matching the behaviour of most .env loaders like dotenv.

Yes. If a single .env file defines the same key more than once, the merger warns about the duplicate. Most .env parsers use the first occurrence, but this is a common source of confusion.

Yes. All processing runs entirely in your browser using JavaScript. Your environment variables — which may contain passwords, API keys, and tokens — never leave your machine and are never sent to any server.

.env files contain KEY=VALUE pairs, one per line. Lines starting with # are comments. Quoted values (KEY="value with spaces") are supported. Empty lines are ignored. Keys are conventionally SCREAMING_SNAKE_CASE (e.g. DATABASE_URL, API_KEY).

Yes. Click 'Add another .env file' to add up to 5 input files. Files are processed left-to-right, with later files overriding earlier ones on conflicts — the same precedence as Docker Compose env_file or dotenv-cli.