Do YAML comments survive conversion to TOML?

No. YAML comments (lines beginning with `#`) are stripped during YAML-to-TOML conversion because the underlying YAML parser discards comments before the data model is constructed. TOML supports comments with the same `#` syntax, but they must be re-added manually after conversion. For configuration files where comments document intent or legal notices, keep the original annotated file and use the converted output only as a base to annotate.

How are YAML anchors handled when converting to TOML?

YAML anchors and aliases are fully resolved (de-referenced) during conversion. The YAML parser expands all `*alias` references to their full anchor values before serializing to TOML. TOML has no anchor/alias equivalent, so repeated structures become explicit inline copies in the output. This is a one-way transformation — converting back to YAML will not re-introduce anchors.

What YAML and TOML specifications are supported?

The tool supports YAML 1.2 (which uses strict boolean rules — only `true`/`false`, not `yes`/`no`/`on`/`off`) and TOML v1.0 (the stable 2021 release). Using YAML 1.2 semantics prevents the common YAML 1.1 bug where `yes`, `no`, `on`, and `off` were accidentally parsed as booleans in Docker Compose and Ansible files. TOML v1.0 support covers dotted keys, inline tables, arrays of tables, and all native scalar types.

OmniToolsKit

YAML ↔ TOML Converter

Name: YAML ↔ TOML Converter
Rating: 5 (2 reviews)
Author: OmniToolsKit

Paste YAML to get TOML, or paste TOML to get YAML

Bidirectional ConvertYAML 1.2 SupportTOML 1.0 OutputOne-click Copy

YAML Input

TOML Output

About this tool

Convert YAML to TOML and TOML to YAML instantly in your browser. This bidirectional YAML↔TOML converter handles YAML anchors/aliases, TOML's strict typing, native datetime values, and inline tables — essential for developers migrating configuration between Rust, Python, Hugo, and cloud-native DevOps toolchains.

About

Bidirectional YAML to TOML Configuration Format Converter

YAML and TOML are both human-readable configuration formats, but they occupy different niches in the developer ecosystem. YAML dominates cloud-native tooling (Kubernetes, GitHub Actions, Ansible, Docker Compose) with its flexible, whitespace-sensitive syntax and support for anchors and aliases. TOML is the format of choice for Rust tooling (Cargo.toml), Python packaging (pyproject.toml), Hugo static sites, and modern developer tools that prioritize predictable parsing and stricter typing.

Converting between YAML and TOML is necessary when adopting new tooling in polyglot environments, when moving project configuration between ecosystems, or when standardizing configuration formats across a monorepo. Key differences to be aware of: TOML has native datetime types (RFC 3339) that map to strings in YAML; YAML supports anchors/aliases for value reuse that must be resolved/expanded in TOML; TOML's boolean and integer types are stricter than YAML's flexible type inference.

All conversion runs entirely in your browser using client-side JavaScript. Configuration files containing sensitive values — API keys, database URLs, cloud credentials — are processed without any server transmission.

What makes it unique

YAML Anchors, Aliases, and TOML's Stricter Type System

YAML anchors (`&base`) and aliases (`*base`) enable DRY configuration by referencing and merging shared values across the document. Since TOML has no equivalent mechanism, YAML-to-TOML conversion resolves all anchors and aliases, producing fully expanded inline values in the TOML output. TOML's type system is stricter than YAML's: booleans must be exactly `true` or `false` (not `yes`/`no`), integers and floats are distinct types, and datetime literals (e.g., `2024-01-15T10:30:00Z`) are first-class TOML values rather than strings — requiring explicit handling during conversion in both directions.

Common Use Cases for YAML to TOML Converter

Migrating Project Configuration to Rust Tooling

Convert YAML-based project configuration files into TOML format for use with Cargo workspaces, rust-analyzer settings, or Rust CLI tool configuration files.

Adapting DevOps Configs for Hugo Static Sites

Convert YAML configuration from Jekyll or other static site generators into Hugo's native TOML format for `config.toml` and front matter migration.

Standardizing Config Format Across a Monorepo

Unify configuration files across a polyglot monorepo by converting between YAML (used by Node.js and Python tools) and TOML (used by Rust and systems tooling).

How to Use

1
Select Conversion Direction
Choose YAML→TOML or TOML→YAML. YAML-to-TOML is most common for Rust and Hugo workflows; TOML-to-YAML is useful when adapting Cargo or pyproject.toml configuration for use in YAML-based CI/CD pipelines.
2
Paste Your Configuration Input
Enter your YAML or TOML content. For YAML input, anchors and aliases are resolved during conversion. The tool validates syntax and reports errors — common YAML issues include tab indentation, missing colons, and incorrect list syntax.
3
Review and Copy the Converted Output
The converted configuration appears with syntax highlighting. Review TOML datetime fields (converted from ISO string YAML values), expanded anchor values, and inline table structures. Copy to clipboard or download as a `.toml` or `.yaml` file.

Features

YAML Anchor and Alias Resolution
Resolves YAML anchors (`&`) and aliases (`*`) including merge keys (`<<`) during YAML-to-TOML conversion, producing fully expanded TOML without reference syntax.
TOML Native Datetime Handling
Converts TOML RFC 3339 datetime literals to ISO 8601 strings in YAML, and optionally detects ISO 8601 string patterns in YAML to restore TOML datetime types during YAML-to-TOML conversion.
Browser-Only Processing — Complete Privacy
All conversion logic runs in your browser via JavaScript. Configuration files containing secrets, API keys, or infrastructure details are never transmitted to any server.

Frequently Asked Questions

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