How This YAML to .env Converter Works
Paste YAML into this yaml to env converter, a yaml to env online tool ready to convert yaml to dotenv output instantly, updating in realtime as you type. Switch direction and it works as a genuine way to convert env file to yaml just as easily. It's built for config deployment, Docker environment setup, and CI pipelines that expect flat environment variables rather than a nested config file.
Nested YAML to Environment Variables
To flatten yaml to env correctly, every level of YAML nesting is joined with an underscore and uppercased, so database: host: localhost becomes DATABASE_HOST=localhost regardless of how many levels deep the key sits, this tool handles nested yaml to env vars at arbitrary depth, not just the first level. Use the optional key prefix field to namespace every generated variable, useful when you want yaml to environment variables output scoped under a consistent APP_ or SERVICE_ prefix.
Converting .env Back to YAML
As a dotenv to yaml converter, env keys are grouped by their first underscore-delimited segment into one level of YAML nesting, APP_DATABASE_HOST and APP_NAME both nest under an app: section. One honest limitation worth knowing, a multi-underscore key like APP_DATABASE_HOST is inherently ambiguous, it could mean a two-level nested path app.database.host or a single key named database_host under app, there's no way to tell which was originally intended once everything has been flattened to underscore-joined env names, so this direction reconstructs one level of nesting rather than guessing at deeper structure.
Quoting and Common Uses
Values are always quoted when they contain a space, a # character, or are empty, regardless of the "Quote values" toggle, since those specific cases would otherwise produce a broken or ambiguous .env line. As a yaml env converter free tool, common uses include turning a Kubernetes or Docker Compose config section into environment variables for a container, or converting a flat .env file into a more readable, structured YAML config for documentation or version control.