YAML Input

TOML Output

What is YAML to TOML Converter?

YAML and TOML are both human-readable configuration formats, but they serve different ecosystems. YAML dominates Kubernetes manifests, Docker Compose files, GitHub Actions workflows, and CI/CD pipelines, while TOML is the standard for Rust projects (Cargo.toml), Python build systems (pyproject.toml), and static site generators (Hugo config.toml). This converter transforms any valid YAML mapping into TOML that follows the v1.0 specification. It handles the structural differences automatically: YAML mappings become TOML tables with [section] headers, sequences of objects become arrays of tables using [[item]] syntax, and sequences of primitives become inline arrays. Type fidelity is preserved throughout — strings, integers, floats, and booleans all convert correctly, and strings that could be misinterpreted as numbers or booleans are automatically quoted in the output.

How to Use

Paste your YAML configuration into the input area — this works best with mapping-style YAML used for Cargo.toml or pyproject.toml structures.
Click 'Convert' to parse the YAML and generate equivalent TOML with proper table headers, arrays, and type quoting.
Review the output for correctness — check that nested objects produced the expected [section.subsection] headers.
Copy the TOML output and paste it into your Cargo.toml, pyproject.toml, or any other TOML-based configuration file.
If the conversion fails, check for YAML-specific features like anchors (&) and aliases (*) which are not supported.

Why Use This Tool?

Migrate Kubernetes or Docker Compose configs into TOML-based tools without manual rewriting

Preserve type fidelity — strings that look like numbers or booleans are automatically quoted in TOML output

Correctly handle arrays of objects using TOML's [[array_of_tables]] syntax, which is the idiomatic way to represent lists of structs

Support deeply nested structures with dotted table headers like [dependencies.serde.features]

Browser-only conversion keeps your configuration files private — nothing is uploaded or stored

Tips & Best Practices

YAML sequences of objects (e.g., a list of dependency entries) become TOML arrays of tables [[key]], which is the standard way to represent repeated structures in TOML.
Strings that could be mistaken for numbers (like version "1.0" or "2021") are automatically quoted — this is required by the TOML spec.
TOML does not support null values; any null entries in your YAML will be omitted from the output.
If your YAML uses anchors (&ref) and aliases (*ref), flatten them before converting since TOML has no equivalent feature.
Top-level keys in your YAML become first-level [sections] in TOML — plan your YAML structure accordingly for clean output.

Frequently Asked Questions

How are YAML types mapped to TOML types?

YAML strings become TOML quoted strings, integers become TOML integers, floats become TOML floats, and booleans become TOML true/false. YAML null values are omitted since TOML has no null type. YAML sequences of primitives become inline TOML arrays [a, b, c], and sequences of objects become arrays of tables [[key]].

When should I NOT use this converter?

Avoid this tool when your YAML relies on features with no TOML equivalent — such as anchors and aliases, multi-document streams (---), custom tags, or complex node types. Also, YAML files that are primarily data dumps with very deep nesting may produce TOML that is harder to read than the original YAML, since TOML requires explicit table headers for every level.

Why would I convert YAML to TOML?

The most common reason is adopting a Rust or Python tool that requires TOML configuration. For example, you might have application settings in YAML that need to become pyproject.toml entries, or infrastructure defaults that should live in a Cargo.toml-compliant format. TOML's stricter grammar also catches configuration errors that YAML's permissive parsing might silently accept.

What happens with deeply nested YAML objects?

Each level of nesting produces a corresponding TOML table header. A YAML path like dependencies > serde > version becomes the TOML header [dependencies.serde] with version as a key underneath. This preserves the full hierarchy in a way that TOML parsers can reconstruct.

Can I convert YAML arrays at the top level?

No. TOML requires a mapping at the root level, so the converter expects a YAML object at the top. If your YAML is a top-level array, wrap it in an object like { items: [...] } before converting.

Is my configuration data sent to any server?

No. All parsing and conversion runs entirely in your browser using JavaScript. Your YAML content and the generated TOML never leave your device. No data is collected, stored, or transmitted.

Real-world Examples

Rust Cargo.toml from YAML

Convert a YAML package manifest into a valid Cargo.toml for a Rust project.

Input

package:
  name: my-rust-app
  version: "0.1.0"
  edition: "2021"
dependencies:
  serde:
    version: "1.0"
    features:
      - derive
  tokio:
    version: "1"
    features:
      - full

Output

[package]
name = "my-rust-app"
version = "0.1.0"
edition = "2021"

[dependencies.serde]
version = "1.0"
features = ["derive"]

[dependencies.tokio]
version = "1"
features = ["full"]

Python pyproject.toml from YAML

Convert a YAML project configuration into pyproject.toml format for a Python package.