Free Online Tool

TOML ↔ JSON Converter

Convert between TOML and JSON instantly in your browser

No data is sent to any server — everything runs client-side

TOML Input

Paste your TOML here

Input

JSON Output

Converted result

Output

What Is TOML?

TOML (Tom's Obvious, Minimal Language) is a configuration file format designed to be easy to read and write. Created by Tom Preston-Werner (co-founder of GitHub), TOML maps unambiguously to a hash table and is intentionally simpler than YAML while being more readable than JSON for configuration files.

TOML has become the standard configuration format for Rust (Cargo.toml), Python (pyproject.toml as defined in PEP 518/621), Hugo static sites, and many other tools. Its strict specification means there are no surprises from implicit type coercion — unlike YAML, NO is always a string, never a boolean.

TOML vs YAML vs JSON

FeatureTOMLYAMLJSON
Comments
Date/time types✓ nativeVia tags✗ (string only)
Deeply nestedVerbose (tables)NaturalNatural
Type ambiguityNoneHighNone
Best forConfig filesInfrastructureData exchange

Common TOML Use Cases

Rust & Cargo

Cargo.toml defines Rust crate metadata, dependencies, features, and build scripts. Convert to JSON for programmatic analysis.

Python pyproject.toml

PEP 621 standardized project metadata in pyproject.toml. Used by pip, Poetry, Hatch, and PDM for Python package configuration.

Hugo & Static Sites

Hugo supports TOML (default), YAML, and JSON for site configuration and front matter.

Deno & Bun configs

Various modern JavaScript runtimes and tools are adopting TOML for configuration as a JSON alternative.

Related Tools

Built by JDApplications