JSON ↔ TOML Converter
Paste JSON to get TOML, or paste TOML to get JSON
JSON Input
TOML Output
Convert between JSON and TOML configuration formats instantly in your browser. Migrate from JSON configs to TOML for Cargo.toml, pyproject.toml, Hugo, and other TOML-native ecosystems.
JSON to TOML Conversion for Configuration File Migration and Management
TOML (Tom's Obvious, Minimal Language) is a configuration file format designed to be human-readable and unambiguous. Introduced by Tom Preston-Werner (GitHub co-founder), TOML has become the standard configuration format for Rust (Cargo.toml), Python packaging (pyproject.toml), Hugo static site generator, .NET projects, and many other modern developer tools. Its key advantage over JSON for configs is readability: TOML is less verbose, supports inline comments, and has native date/time types and multi-line strings.
However, much of the software ecosystem still generates or consumes JSON, creating an ongoing need to convert between the two formats. Developers frequently need to migrate a JSON configuration into TOML for a Rust project, convert a TOML config to JSON for an API that expects JSON, or understand how a TOML file maps to its JSON schema equivalent.
OmniToolsKit's bidirectional JSON↔TOML converter handles all TOML data types including strings, integers, floats, booleans, datetime values, arrays, and inline tables. It validates both input formats, reports syntax errors with line numbers, and pretty-prints TOML output with proper section headers and key grouping. All conversion runs client-side in your browser — no uploads, no API calls, no data transmission.
TOML Section Grouping and Comment-Aware Conversion
Unlike basic JSON-to-TOML converters that produce flat key=value output, OmniToolsKit groups nested objects into TOML table sections (`[section]`) and arrays of tables into `[[array]]` blocks, producing idiomatic TOML that's structured exactly as human authors would write it. TOML comments are preserved in TOML-to-JSON conversion metadata where possible, so documentation entries aren't silently lost when round-tripping configurations.
Migrating Package Config to pyproject.toml or Cargo.toml
Convert an existing JSON-based package configuration into a TOML format suitable for pyproject.toml (Python packaging) or Cargo.toml (Rust) during project modernization.
Working with Hugo Static Site Configuration
Convert Hugo configuration objects between JSON and TOML as you migrate or document site configuration. Hugo supports both formats and switching between them is common.
Validating TOML Config File Syntax
Paste a TOML file to validate its syntax and see it converted to JSON to verify the parsed structure matches your expectations before using it in production.
Understanding TOML to JSON Schema Mapping
Convert TOML configs to JSON to understand how TOML table sections map to JSON objects, especially when debugging integration with JSON-Schema validators or API config endpoints.
- 1
Paste JSON or TOML into the Input Panel
Paste a JSON object or TOML configuration into the input editor. The tool automatically detects the format based on syntax, or you can manually select the input format using the tabs.
- 2
Select Conversion Direction
Use the direction toggle to switch between JSON→TOML and TOML→JSON modes. The output panel updates immediately when you change the direction or modify the input.
- 3
Review Converted Output and Validation Errors
The converted result appears in the output panel. If the input has syntax errors, a clear error message shows the location and description. Valid input produces pretty-printed, well-structured output.
- 4
Copy or Download the Result
Click 'Copy to Clipboard' or 'Download' to save the result as a .toml or .json file. Paste the output directly into your project's configuration file.
Bidirectional JSON↔TOML Conversion
Convert from JSON to TOML and TOML to JSON with a single click. Both directions produce well-formatted, idiomatic output with proper type handling.
TOML Table Section Grouping
Nested JSON objects are converted to TOML `[table]` sections and arrays of objects to `[[array of tables]]`, producing human-readable TOML that follows community conventions.
Native TOML Type Support
Handles all TOML native types: strings, integers, floats, booleans, RFC 3339 datetime values, arrays (including mixed-type), and inline tables — preserving type semantics during round-trip conversion.
Syntax Validation with Error Reporting
Both JSON and TOML inputs are validated before conversion. Syntax errors are reported with the line number and a specific description of the parsing failure.
Pretty-Printed Output
Output is formatted for readability: TOML keys are properly grouped into sections, JSON is indented with 2 spaces, and both formats are sorted consistently for easy diff and review.
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.
Found this tool useful?
Share your experience and help others discover it.