JSON / YAML / TOML Converter
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JSON / YAML / TOML Converter
Convert between JSON, YAML, and TOML data formats instantly. Client-side only — your data never leaves your browser.
All conversions happen locally in your browser. No data is sent to any server.
Why Convert Between JSON, YAML, and TOML?
Modern software projects use different data serialization formats depending on the ecosystem. Docker Compose and Kubernetes rely on YAML for its human-readable indentation-based syntax. Rust's Cargo and Python's pyproject.toml use TOML for its simplicity and explicit table structure. Meanwhile, JSON remains the universal format for APIs, package.json files, and configuration in JavaScript/TypeScript ecosystems. Developers frequently need to convert between these formats when migrating configurations, comparing settings across tools, or porting projects between languages.
Understanding Format Differences
JSON is the strictest format — it requires quoted keys, does not allow comments, and uses explicit delimiters (braces and brackets). YAML is whitespace-sensitive and supports comments, anchors, and multi-line strings, making it powerful but occasionally error-prone due to indentation mistakes. TOML sits between them: it uses explicit key = value syntax with [section] headers, supports comments with #, and avoids indentation-sensitivity issues. Each format has trade-offs: JSON for machine interoperability, YAML for human readability of complex nested structures, and TOML for simple, unambiguous configuration files.
Tips for Clean Conversions
When converting between formats, keep in mind that not all features are portable. YAML comments are discarded when converting to JSON (which has no comment syntax). TOML requires top-level tables, so JSON arrays at the root level must be wrapped in an object first. Date values in TOML are native types but become strings in JSON. For the cleanest results, use well-structured objects with string, number, boolean, and array values — these translate seamlessly across all three formats.
Frequently Asked Questions
What is the difference between JSON, YAML, and TOML?
JSON (JavaScript Object Notation) uses curly braces and square brackets with strict syntax. YAML (YAML Ain't Markup Language) uses indentation-based formatting and is popular for configuration files like Docker Compose and Kubernetes. TOML (Tom's Obvious, Minimal Language) uses key-value pairs with sections in brackets and is commonly used in Rust (Cargo.toml) and Python (pyproject.toml) projects.
Is my data safe when using this converter?
Yes. All conversions happen entirely in your browser using JavaScript. No data is transmitted to any server. You can verify this by using the converter while offline — it works without an internet connection.
Why can't I convert a JSON array to TOML?
TOML only supports top-level tables (objects/maps), not arrays. If your JSON starts with a square bracket ([), wrap it in an object first, e.g., {"items": [...]}. JSON objects and YAML mappings convert to TOML without issues.