TOML Format Guide & Converter

Tom’s Obvious Minimal Language is a minimal, typed configuration file format popular with Rust and modern CLIs, introduced by Tom Preston-Werner (2013). TOML aims for obvious semantics: tables, typed values, and fewer surprises than YAML edge cases. Convert to JSON when an API or web tool only accepts JSON.

Full name

Tom’s Obvious Minimal Language

Kind

structured data

File extension

.toml

MIME type

application/toml

Developer / standard

Tom Preston-Werner · 2013

Compression

none

Quality model

Lossless / not lossy

Container

No / single bitstream typical

Common codecs

—

Technical sources

—

Transparency

Not supported

Animation

No (still / non-animated typical use)

Typical size

Tiny for most configs

Browser support

Convert privately in Format Convertly; open in any text editor

Compatibility

First-class in Rust/Cargo and many modern CLIs; convert to JSON when a web service or legacy tool only accepts JSON

TOML compression: none. Lossless (or non-destructive packaging) keeps reconstructable data — size savings come from packing efficiency, not throwing detail away. Typical size profile: Tiny for most configs. Quality note: Lossless structured text for configuration

Quality: Lossless structured text for configuration

Typical size: Tiny for most configs

TOML does not support an alpha channel. Convert to PNG, WebP, AVIF, or SVG when you need transparent backgrounds.

TOML is a still-media or non-animated format in typical use. Use GIF, APNG, video, or animated WebP when you need motion.

Usually none beyond encoding/BOM — structure is the content. Comments allowed in YAML/TOML.

• Cargo and Rust tooling
• Modern CLI app config
• Human-edited service settings
• Replacing ad-hoc INI with clearer types

• Deeply nested documents better as JSON
• End-user documents
• Binary data
• Teams standardized only on YAML without tooling

• Readable tables
• Typed values
• Less ambiguous than some YAML
• Great for app config

• Younger ecosystem than JSON/YAML in places
• Not a wire API default
• Easy to break with duplicate keys depending on parser
• Not for prose documents

First-class in Rust/Cargo and many modern CLIs; convert to JSON when a web service or legacy tool only accepts JSON

Browsers: Convert privately in Format Convertly; open in any text editor

• Format Convertly
• Cargo
• VS Code
• Neovim

• Desktop and mobile browsers for conversion
• Modern desktops
• Phones and tablets with compatible apps

Edit TOML in VS Code or any text editor with syntax highlighting. Validate before deploy — a missing quote can break Cargo or CLI startup.

Convert TOML to JSON in Format Convertly when the next tool in your pipeline needs JSON — configuration stays local in the browser.

• Pick a target format from popular conversions or the full list below.
• Your file is read into browser memory — not uploaded to a server.
• Download the result when conversion finishes.

Incoming conversions strengthen the TOML cluster — e.g. JPG → TOML, PNG → TOML.

Decision pages that cite TOML — the next hop after a vs comparison.

Tools extend the format graph beyond one-off conversion — compression, metadata, and utilities for real workflows.

Uploading sensitive TOML files to a random converter creates a third-party copy you cannot control. Format Convertly keeps processing on-device so photos, contracts, and exports stay private.