Tablizer

Convert YAML to Ruby Online

Paste a YAML table below, edit it if you need to, and get Ruby 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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Nothing here is uploaded. The parsing happens on this page.
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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 Ruby is

A Ruby array of hashes with symbol keys.

Rails seed files and Ruby scripts.

What changes when you convert YAML to Ruby

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.

Column names are converted to valid symbol names, which means non-word characters become underscores.

What carries over from YAML to Ruby

Ruby can express everything YAML holds about a table, so this conversion is about shape rather than loss.

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

The identifier 007 comes out of the Ruby 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 Ruby file goes wrong.

The quotes around Jonah "Jo" Pryce are left as a plain quote character in the Ruby.

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"
Ruby out
staff = [
  { 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' },
]

Questions

How do I convert YAML to Ruby?

Paste your YAML into the box above or drop the file onto it. Check the table in the grid, then copy or download the Ruby 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.

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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