Explicit version modes
Choose TOML 1.0 or 1.1 for each invocation. Use --toml-version 1.0 for files read by Cargo or other 1.0-only tools.
TOML 1.0 + 1.1 · Rust
TOMLSMITH
Check and format TOML.
Use TomlSmith from Rust, the command line, an editor, or the browser. Each interface supports explicit TOML 1.0 and 1.1 modes.
- 1,360 / 1,360
- toml-test decoder cases pass for TOML 1.0 and 1.1
- 2 modes
- published TOML 1.0 and 1.1 specifications implemented separately
- 3 commands
- check · fmt · parse
- 4 surfaces
- Rust library · CLI · language server · browser playground
01 — Measured performance
TOML 1.0 format and check, compared
Direct-CLI cold-start medians; package-manager launchers and wrapper processes are excluded. See TOML 1.1 and all four lanes.
Format · TOML 1.0
median latency · lower is betterCheck · TOML 1.0
median latency · lower is better* tomll does not preserve comments or literal styles.
02 — Features
What TomlSmith does
Choose TOML 1.0 or 1.1, then run check, fmt, or parse.
Check documents
check reports errors and warnings with source ranges and diagnostic codes.
Formatting with safeguards
Formatting preserves comments and literal spellings in covered cases. Documents with parse or semantic errors are not rewritten, and fmt --check checks files without changing them.
Read JSON output
parse emits the selected version, validity, and diagnostics as JSON for scripts and tools.
Use the Rust API
Parse once with Document, then query diagnostics, formatted output, highlights, and decoded values.
Use an editor or browser
Connect an LSP-capable editor, use the VS Code client, or run the browser playground.
03 — Projects
Project repositories
TomlSmith is split across five repositories. Each repository has a separate role.
Core
tomlsmith
The Rust library, CLI, and language server, including parsing, diagnostics, formatting, highlighting, and decoded values.
Browsertomlsmith/playground
A browser workbench built with WebAssembly. It runs locally in the tab and does not upload source.
Editortomlsmith/vscode-plugin
The VS Code client for tomlsmith-lsp: diagnostics, formatting, semantic highlighting, hover, symbols, and folding.
Benchmarkstomlsmith/benchmark
Cold-start CLI measurements for TOML checkers and formatters, with correctness checks before timing.
Brandtomlsmith/icon-assets
Source files and exports for the project icon, favicons, editor icon, avatars, and social previews.
JoinContributing
Read the contribution guide before opening an issue or pull request. Contributions use the MIT license.
Try TomlSmith
Follow the quick start, or use the browser Playground without installing anything.