YAML to .env Converter

Configuration written as YAML has a habit of needing to become a .env file: the environment block in a docker-compose.yml gets extracted for local development, a Kubernetes ConfigMap is copied onto a laptop, a CI workflow exports its variables, or a config management UI hands you YAML and your entrypoint only understands KEY=value. Hand-rebuilding the file is slow and error-prone — quotes get dropped, nested structures collapse, and escaped characters lose their meaning.

The YAML to .env Converter turns any mapping into valid, prettified .env output in one click. Nested objects are flattened into FEATURE__DARK_MODE-style keys with a configurable separator, single- and double-quoted values are unwrapped with their escapes resolved, and inline comments never leak into the output. Type detection maps yes/no/on/off/true/false to real booleans, keeps numeric values numeric, and turns null or ~ into an empty value — exactly how dotenv-based loaders expect to read them.

Everything runs locally in your browser. Your secrets never leave the page, values that need quotes are escaped correctly for round-tripping, list items are flagged instead of silently mangled, and duplicate keys are reported by line number.

• One-click conversion: paste YAML, get clean. env lines.
• Nested flattening: FOO: { BAR: 1 } becomes FOO__BAR=1 with a configurable separator.
• Quote unwrapping: single- and double-quoted values are decoded correctly.
• Escape resolution: \n, \t, \\ and \" in double-quoted values become real characters.
• Type-aware output: yes/no/on/off/true/false map to booleans; numbers stay numeric; null becomes empty.
• Smart .env quoting: values with spaces, #, = or quotes are double-quoted and escaped for round-trips.
• Comment safety: full-line comments and inline comments outside quotes are stripped.
• Duplicate detection: repeated keys are reported with their line numbers.
• Copy / download: clipboard or a real .env file in one click.
• Private: all conversion happens in your browser.

1. Paste your YAML mapping into the input box, or click Load sample to see a nested example with quoted strings and inline comments.
2. Choose your options. Toggle nested flattening and set the separator (default __), or disable nesting to keep only top-level keys.
3. Set type detection to map YAML booleans, numbers and null to the right .env representation.
4. Click Convert. The .env content appears instantly with a stats line.
5. Review warnings. Unsupported list items and duplicate keys are listed above the output.
6. Copy or download the result as a .env file.

Example 1 — Compose environment block. A developer extracts the environment: section of a docker-compose service and converts it to .env for local dotenv use. APP_NAME, PORT and DEBUG arrive as clean KEY=value lines with correct types.

Example 2 — ConfigMap export. An operator copies the data: section of a Kubernetes ConfigMap into this tool and downloads a .env file that mirrors the cluster configuration for troubleshooting on a workstation.

Example 3 — Nested feature flags. A product team stores feature: { dark_mode: true, analytics: false } in a config service. Flattening produces FEATURE__DARK_MODE=true and FEATURE__ANALYTICS=false, dropping straight into any dotenv-compatible loader.

Example 4 — Escaped connection strings. A connection string stored as "postgresql:\/\/user:pass@db:5432\/app" is unescaped to the plain URL, then written to DATABASE_URL with the exact characters your driver expects.

Example 5 — CI variable migration. A platform engineer converts the variables block of a .gitlab-ci.yml into a checked-in .env so all developers start with identical configuration during migration.

• No hand-rebuilding: the .env is derived from the YAML, never retyped.
• Nesting handled: structured mappings become keys every loader understands.
• Quotes and escapes correct: values round-trip with no lost characters.
• Right types: booleans, numbers and null match runtime expectations.
• Safe errors: lists and duplicates are flagged, not silently mangled.
• Private & free: no upload, no account, instant results.