TOML to JSON & JSON to TOML ConverterTOML v1.0
Zero-transmission client-side parser for Rust Cargo.toml, Python pyproject.toml, and cloud configs.
Rust Cargo.toml & Python pyproject.toml Online Parser Guide
Modern programming ecosystems rely heavily on TOML (Tom's Obvious Minimal Language) as the primary configuration and package manifest format. Rust standardized on Cargo.toml for crate declarations, while Python unified tooling via pyproject.toml (PEP 518 & PEP 621).
Cargo manifests define [package] metadata, feature flags in [features], and granular dependency versions. Converting Cargo.toml to JSON enables direct ingestion into CI/CD scripts, automated vulnerability scanners, and dependency visualization tools without needing the Rust cargo CLI on the host.
➞ "tokio": { "version": "1.38", "features": ["full"] }
With PEP 621 standardization, tools like Poetry, Hatch, Flit, Ruff, and Pytest converge into one centralized pyproject.toml. Converting this file into JSON simplifies automated pipeline validations, GitHub Action step matrix generation, and monorepo metadata extraction.
test = ["pytest>=8.0"]
➞ "test": ["pytest>=8.0"]
TOML vs JSON vs YAML: Comprehensive Format Comparison
Choosing the right serialization format depends on whether human readability, machine efficiency, or complex hierarchy is prioritized.
| Feature / Metric | TOML (v1.0) | JSON (RFC 8259) | YAML (1.2) |
|---|---|---|---|
| Primary Purpose | Human Configuration | Machine Data Interchange | Complex App Manifests |
| Comments Support | ✓ Yes (# comment) | ✗ No comments | ✓ Yes (# comment) |
| Native Date/Time Types | ✓ Full RFC 3339 | ✗ Strings only | ✓ Timestamp types |
| Indentation Sensitivity | Whitespace Insensitive | Whitespace Insensitive | Strict Indentation |
| Key Ecosystems | Cargo (Rust), Poetry (Python), Hugo | Web APIs, NPM, REST, Cloud Storage | Kubernetes, GitHub Actions, Docker |
TOML 1.0 to JSON Data Type Mapping
Basic strings ("text") and multi-line literal strings ('''block''') map to standard JSON strings with escaped linebreaks.
Decimal numbers, hex (0xDEAD), octal, binary, and floats map directly to JSON numeric values. Underscores like 1_000_000 are parsed as numbers.
RFC 3339 timestamps (e.g. 2026-10-11T23:30:00Z) map into ISO 8601 string representations in JSON.
Inline tables like { x = 1, y = 2 } map directly to standard JSON dictionary objects { "x": 1, "y": 2 }.
Double bracket syntax [[products]] translates cleanly into a JSON array of objects "products": [ {...}, {...} ].
Strict lowercase true and false literals map directly to JSON native booleans.
Frequently Asked Questions (FAQ)
No, absolutely not. All parsing and stringification operations run 100% inside your local browser tab using client-side JavaScript execution. Zero network packets or analytical payloads are transmitted to any backend.
By definition in the official TOML 1.0 specification, the root of every TOML document must be a table (a key-value mapping). Therefore, top-level JSON arrays (like [1, 2, 3]) cannot form a valid standalone TOML document. To convert them, wrap the array in an enclosing object such as { "items": [...] }, or use the one-click auto-fix button above.
TOML does not have a null data type. In dictionary objects, null fields are omitted. In arrays, nulls are disallowed by TOML. When the "Filter Nulls" toggle is enabled, null values inside arrays are automatically pruned so conversion succeeds smoothly without errors.
Yes! Our parser is fully compliant with the TOML 1.0 specification, effortlessly handling Cargo workspaces, optional dependencies, conditional compilation feature flags, and custom release profiles.