Tablizer

Convert YAML to TOML Online

Paste a YAML table below, edit it if you need to, and get TOML back. The conversion runs in your browser, so nothing is uploaded, there is no size limit and there is no signup.

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The output will appear here once there is a table to convert.

What YAML is

YAML uses indentation instead of brackets. It is a superset of JSON, supports comments, and is meant to be edited by hand.

Kubernetes manifests, CI pipelines, Ansible playbooks and most modern config files.

What TOML is

TOML is a configuration format with explicit types and a table syntax, designed to be unambiguous where YAML is clever.

Rust and Python projects, and anything with a pyproject.toml or Cargo.toml.

What changes when you convert YAML to TOML

A YAML list of maps reads as rows and columns directly. Anchors and aliases are resolved before the table is built, so a repeated block arrives expanded rather than as a reference.

Each row becomes an entry in an array of tables. Keys are sanitised to bare keys where possible and quoted where not.

What carries over from YAML to TOML

YAML records 2 things about a table that TOML has no way to hold.

An empty cell and a missing one are the same thing in TOML, so a null and an empty string in the YAML both come out blank and can no longer be told apart.

YAML can hold a value that is itself a list or an object. TOML has only flat cells, so nested values are flattened into one cell rather than being spread across columns.

Both formats record types, so numbers, booleans and nulls survive as themselves rather than as text.

The identifier 007 comes out of the TOML as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.

The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a TOML file goes wrong.

The quotes around Jonah "Jo" Pryce are escaped with a backslash in the TOML.

A worked example

Three rows of staff data, with an identifier that has a leading zero, a value containing a comma, a value containing quotes and one blank cell. Those are the four places formats disagree, so they are the four places to look.

YAML in
- id: "007"
  name: Halima Yusuf
  role: Analyst, data
  started: "2024-03-15"
  hours: "38.5"
- id: "012"
  name: Jonah "Jo" Pryce
  role: Engineer
  started: "2025-11-02"
  hours: ""
- id: "104"
  name: Wei Chen
  role: Manager
  started: "2023-06-30"
  hours: "40"
TOML out
[[staff]]
id = "007"
name = "Halima Yusuf"
role = "Analyst, data"
started = "2024-03-15"
hours = "38.5"

[[staff]]
id = "012"
name = "Jonah \"Jo\" Pryce"
role = "Engineer"
started = "2025-11-02"
hours = ""

[[staff]]
id = "104"
name = "Wei Chen"
role = "Manager"
started = "2023-06-30"
hours = "40"

Questions

How do I convert YAML to TOML?

Paste your YAML into the box above or drop the file onto it. Check the table in the grid, then copy or download the TOML from the output panel. It takes one step and the data never leaves your browser.

Why did my YAML value change meaning?

YAML reads several bare words as booleans. In the 1.1 spec that includes yes, no, on and off, which is why a country column containing NO for Norway can arrive as false. Quote values you want kept as text.

What happens to nested values?

TOML has no nested cell, so a list or object inside a YAML value is flattened into a single cell rather than expanded into extra columns. Split it before converting if the parts need to be separate.

Is there a limit on file size?

No. The work happens on your own machine, so the limit is your machine's memory rather than an upload cap. A file with tens of thousands of rows converts in a second or two.

Is my data uploaded anywhere?

No. The parsing and generating are done by JavaScript running on this page. You can watch the network tab while you convert and see that nothing is sent.

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