TOML ↔ JSON Converter

What is TOML ↔ JSON Converter?

TOML-JSON Converter transforms data between TOML (Tom's Obvious Minimal Language) and JSON with full support for TOML-specific features including dotted keys, inline tables, arrays of tables, local date-times, and multi-line strings. It validates TOML syntax according to the TOML v1.0.0 specification and provides clear error messages for malformed documents.

Rust developers working with Cargo configuration, Python developers editing pyproject.toml, and DevOps engineers converting between configuration formats. The tool runs entirely in your browser — your data never leaves your device.

How to Use TOML ↔ JSON Converter

1. Paste your TOML content in the left panel or JSON in the right panel
2. Click the conversion arrow to transform in either direction
3. Review syntax validation results — errors point to the specific line and column
4. Adjust formatting options for the output — indentation and key ordering
5. Copy the converted result or download it as a file

Common Use Cases

• Converting Cargo.toml (Rust) configuration to JSON for tooling that requires JSON input
• Transforming pyproject.toml (Python PEP 621) into JSON for automated processing
• Converting Hugo or Zola static site TOML configs to JSON for templating engines
• Migrating configuration files between formats when a project switches config standards
• Validating TOML syntax before committing configuration changes to a repository

Pro Tips

• TOML's [[array]] syntax creates arrays of tables — this maps to JSON arrays of objects and is commonly used for multiple dependencies or server configurations
• Dotted keys like [server.http] create nested objects — server = { http = {} } in JSON — keep nesting depth reasonable for readability
• TOML distinguishes between local dates (2024-01-15), local times (14:30:00), and offsets (2024-01-15T14:30:00Z) — all are converted to strings in JSON since JSON has no native date type

Why Use This Tool?

• Privacy-first: All processing happens locally in your browser. No data is transmitted to any server.
• No installation required: Works in any modern browser on desktop or mobile.
• Completely free: No account, no credit card, no usage caps.
• Fast and reliable: Powered by modern Web APIs for near-instant results.

Related Concepts

Learn more about related topics: TOML v1.0.0, Cargo.toml, pyproject.toml, INI format.

Frequently Asked Questions