YAML to TOML
ConverterConvert YAML data to TOML format with nested structures and typed values, handling null explicitly when switching config across toolchains and CI systems.
Related Tools
About YAML to TOML
Moving configuration from YAML to TOML happens all the time — consolidating CI/CD parameters or Docker Compose settings into a single pyproject.toml or Cargo.toml, or adopting TOML as a team's canonical format. This tool parses YAML locally and produces TOML 1.0-compliant output, translating nested mappings into tables ([server]), sequences of objects into arrays of tables ([[server]]), and preserving scalar types, RFC 3339 date-times, and multi-line string blocks. The conceptual shift to keep in mind is that YAML expresses nesting through indentation while TOML uses bracketed table headers, so the same data reads flatter in TOML. Also note TOML has no null type: keys with null values are dropped, and anchors are expanded since TOML has no reference mechanism. For example, YAML server: host: localhost converts back to a [server] TOML table for Cargo- or pyproject-style tools, entirely in your browser with nothing uploaded.
How to Use
- Open the YAML to TOML tool
- Select the source and target formats
- Adjust the output options as needed
- Click the Convert button; results appear in real time
- Copy or export the result
Use Cases
- Organize tool config — Consolidate scattered YAML settings into a single TOML file for a Rust/Python project.
- Standardize format — Convert legacy YAML uniformly once a team mandates TOML.
- Learn syntax — Compare YAML and TOML to understand TOML-specific structures like arrays of tables.
- Simplify config — Reorganize overly deep YAML into TOML's flatter table structure.
- Generate examples — Provide both YAML and TOML versions in docs for reference.
- Migrate CI variables — Convert GitHub Actions workflow YAML inputs into TOML to centralize config in a pyproject.toml file.
- Docker Compose to TOML — Translate docker-compose YAML service definitions into TOML for tools that read TOML-based orchestration configs.
FAQ
What happens to YAML null?
TOML has no null. Keys with null values are skipped during conversion — note these fields disappear from the result.
Are YAML anchors preserved?
No. Anchors and references are expanded into actual content before conversion, since TOML has no reference mechanism.
What do object arrays become?
They become TOML arrays of tables [[name]], with each array element as a table block.
Why are some keys quoted?
When key names contain dots, spaces, or special characters, TOML requires quoting — handled automatically.
How are YAML multi-line strings handled?
Long text becomes TOML triple-quoted multi-line strings preserving line breaks; fold lines with a trailing backslash when you want softer wrapping.
Want JSON as an intermediate?
Use YAML to JSON then JSON to TOML — two steps give more control.