ENV to Docker Compose

What this tool converts

This tool parses standard .env-file syntax (KEY=value per line, comments and blank lines ignored, quotes stripped) and emits a ready-to-paste docker-compose environment block in one of two styles: Inline lists every variable directly under a services.app.environment key, while env_file emits a short snippet pointing at env_file: - .env so Compose loads the file itself at runtime instead of inlining values into the YAML.

The generated snippet always uses a placeholder service name (app) since the tool has no way to know your actual service name from .env content alone — rename it to match your compose file before pasting it in.

When to use it

Use it when scaffolding a new docker-compose.yml from an existing .env file and you don't want to hand-transcribe every variable into YAML's list syntax (easy to mistype the leading - and indentation). The Inline style is useful for small services or when you want the environment visible directly in version control; the env_file style is better when the .env file itself is already gitignored and you just need the one-line reference added to your compose service.

If you actually need the .env content as a JSON object instead of YAML — for a Node config loader or a test fixture — use the companion ENV to JSON tool on the same input.

Example

Input DB_HOST=localhost\nDB_PORT=5432 with Inline style produces:\nservices:\n app:\n environment:\n - DB_HOST=localhost\n - DB_PORT=5432\nSwitching to env_file style instead produces a fixed three-line snippet referencing env_file: - .env, regardless of how many variables are in the input, since it points at the file rather than listing values.