4 Free Online Format Converters
Configuration and documentation move between formats constantly, and these 4 converters handle the pairings that the JSON category does not already cover. Markdown ⇄ HTML converts in both directions with a live preview, which is what you need when a CMS wants HTML but you write in Markdown, or when you are pulling documentation out of a rendered page and back into a repository. TOML to JSON does the same for configuration — TOML is what Cargo, Poetry, and Netlify read, JSON is what tooling and scripts prefer — and converts back so you can hand-edit either side. YAML to Go generates Go structs with yaml and json tags from a YAML document, which turns a Kubernetes manifest or a CI config into a typed model without transcribing every field by hand. All three run in the browser.
All 4 Other Converters tools
What you can do with these converters
Each is bidirectional or code-generating, rather than a one-way dump.
- Markdown to HTML — render GitHub Flavored Markdown, including tables, task lists, and fenced code, into clean HTML with a live preview.
- HTML to Markdown — go the other way, turning a rendered page or a CMS export back into Markdown source you can commit.
- TOML to JSON and back — convert config with tables, arrays, and typed values preserved in both directions.
- YAML to Go — infer idiomatic Go structs with yaml and json struct tags and nested types from a sample YAML document.
Choosing a config format
The three formats are not interchangeable in spirit even when a converter maps between them cleanly. JSON has no comments and no trailing commas, which makes it excellent for machines and irritating for humans editing by hand. YAML is readable and comment-friendly but significant-whitespace sensitive, and its type coercion has famous surprises — the Norway problem, where an unquoted country code becomes a boolean. TOML sits in between: explicit types, comments allowed, no indentation traps, which is why the Rust and Python packaging ecosystems settled on it. Converting from YAML to JSON is a good way to see exactly how a parser interpreted your indentation and unquoted values, before that interpretation surprises you in production.