# Structured Data Converter

> Free YAML ↔ JSON ↔ TOML converter with multi-document YAML support, anchor resolution, and zero network requests. No signup required.

- **Category:** Developer
- **URL:** https://www.teafun.cyou/tools/yaml-json-toml/
- **Privacy:** Runs entirely in your browser — no uploads, no account, no tracking.
- **Also known as:** yaml, yml, toml, config converter, structured data, yaml to json, json to yaml, convert config
- **Related tools:** [JSON Formatter & Validator](https://www.teafun.cyou/tools/json-formatter/), [ENV / Shell / Docker Converter](https://www.teafun.cyou/tools/env-converter/), [Log Formatter](https://www.teafun.cyou/tools/log-formatter/)
- **Tags:** Data, Conversion, Formatting

## About

Convert YAML, JSON, and TOML locally in your browser with multi-document YAML support and anchor resolution.

## How to Use the Structured Data Converter

Pick **From** and **To** formats. Paste source or **Import file** from disk. The result appears live. The Swap button reverses From-To and moves the output into the input (useful for round-trip testing — `YAML -> JSON -> YAML` should be idempotent except for comment loss and key ordering). For multi-document YAML separated by `---`, the converter emits a JSON array (one element per document) or concatenates back to multi-doc YAML in the reverse direction. Anchors (`&name`) and aliases (`*name`) are resolved before conversion — the output has the expanded values, not the references. The error pane lists the line and column where parsing failed, with a context window: a missing `]` in JSON, broken indentation in YAML, or an unquoted special character in TOML are the three most common issues. Download as `.json`, `.yaml`, or `.toml` — the file extension matches the target format so editors apply the right syntax highlighting.

## Why Config Format Conversion Matters

Format choice signals intent. JSON is for wire-format and tooling that needs unambiguous parsing — every `{` and `[` is exactly one thing. YAML is for humans authoring configuration with cross-references (anchors avoid copy-pasting blocks of env vars across services). TOML is for explicit-typed configuration where mixing strings and dates accidentally is unacceptable (`Cargo.toml` would not tolerate the Norway problem). When migrating a project, conversions reveal mismatches: a YAML file with `country: NO` becomes JSON `country: false` if the parser is YAML 1.1, breaking downstream systems silently. A TOML date converted to JSON loses its type — round-tripping back to TOML produces a string, breaking config validators that expect `datetime`. The converter surfaces these by preserving type information across all three formats where possible, so what you read in equals what you write out — modulo comments, which YAML and TOML support but JSON does not.

_SEO title: Structured Data Converter – YAML, JSON, TOML | TeaFun_

## FAQ

### Can it handle multi-document YAML?

Yes. When the input contains multiple YAML documents separated by --- the converter keeps them together and can export them as a JSON array or YAML multi-doc output.

### Why can't multi-document YAML convert directly to TOML?

TOML is best suited to a single object document. If you paste multiple YAML documents, convert them to JSON first or merge them before exporting to TOML.

### Are YAML anchors and aliases resolved?

Yes. Anchors and aliases are resolved in the browser before the converted output is generated.