Konverter
TOML ↔ YAML
The TOML ↔ YAML Converter translates between TOML (Tom's Obvious Minimal Language) and YAML (YAML Ain't Markup Language) in both directions. Both are human-friendly configuration formats popular in the DevOps and development world. Converting between them is useful when migrating a project's configuration format or when a tool requires one format but your source is in the other.
TOML vs YAML – key differences
TOML and YAML are both designed to be human-readable configuration formats, but they differ in important ways. TOML has explicit, unambiguous types (integer, float, datetime, boolean, string) and a simpler grammar that avoids the common pitfalls of YAML. TOML supports comments with # and uses [section] headers for nesting. YAML uses significant whitespace (indentation) for structure, is more flexible with multi-line strings and complex data types, and is a superset of JSON. YAML's flexibility also makes it more error-prone – indentation mistakes and type coercion surprises (yes/no treated as booleans) are common issues. TOML is favored for simple configuration files; YAML is prevalent in Kubernetes, Docker Compose, Ansible, and CI/CD systems.
How does the converter work?
For TOML-to-YAML, the tool parses the TOML into an internal data tree using a spec-compliant parser, then serializes the tree as YAML. TOML tables become YAML mappings, array of tables become YAML sequences of mappings, and TOML datetimes become YAML datetime scalars. For YAML-to-TOML, the tool parses the YAML (resolving anchors and aliases) and converts the resulting tree to TOML. Arrays of heterogeneous types and null values present in YAML are flagged as incompatible with strict TOML since TOML does not support mixed-type arrays or null.
Typical Use Cases
- Migrating a project's configuration from TOML to YAML for compatibility with Kubernetes or Helm
- Converting a YAML Ansible playbook variable file to TOML for a Rust project
- Comparing how the same configuration looks in TOML vs YAML syntax
- Checking whether a YAML config file can be losslessly represented in TOML
Step-by-step Guide
- Step 1: Paste your TOML or YAML content into the input field.
- Step 2: Select the conversion direction: TOML → YAML or YAML → TOML.
- Step 3: The converted output appears in the result area with correct formatting.
- Step 4: Copy or download the output for use in your project.
Example
Input
[server] host = "localhost" port = 8080
Output
server: host: localhost port: 8080
Tips & Notes
- YAML does not have a null type symbol as explicit as TOML's absence of a value – null in YAML is represented as ~ or the word null.
- TOML requires all values in an array to be of the same type; if your YAML has mixed-type arrays, you must restructure them before converting to TOML.
- YAML comments are lost when converting to TOML and then back, since both formats support comments but they cannot be round-tripped through the data tree.
Frequently Asked Questions
Can YAML's null be represented in TOML?
No. TOML does not have a null type. Keys with null values must either be omitted from the TOML output or represented as an empty string, depending on your use case.
Does the converter handle YAML anchors?
Yes. YAML anchors and aliases are resolved during parsing, and the resulting inlined values are written to the TOML output. TOML has no concept of references.
Which format should I use for a new project?
TOML is recommended for simple, flat configuration files (e.g. Rust, Python project metadata). YAML is better for complex hierarchical configurations (e.g. Kubernetes manifests, Helm charts, GitHub Actions). Choose based on what your toolchain expects.
TOML ↔ YAML
Convert TOML to YAML and YAML to TOML — live, bidirectional, and with syntax validation.
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