Tablizer

Convert JSON to Ruby Online

Paste a JSON 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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What JSON is

JSON is a text format for nested data: objects with named keys, arrays, strings, numbers, booleans and null. It has no date type and no comments.

Every web API, most configuration files and anything that talks to JavaScript.

What Ruby is

A Ruby array of hashes with symbol keys.

Rails seed files and Ruby scripts.

What changes when you convert JSON to Ruby

Four shapes all read correctly: an array of objects, an array of arrays with a header row, an object of column arrays, and an object keyed by row id. A single wrapper key holding the array, which is how most APIs reply, is unwrapped automatically. Nested objects are flattened one level into dotted keys; anything deeper is kept as JSON text in the cell, because a table cannot hold a tree.

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

What carries over from JSON to Ruby

Ruby can express everything JSON 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.

JSON 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 JSON to Ruby?

Paste your JSON 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 zip code lose its leading zero?

Type inference turned the text 07030 into the number 7030. Tablizer leaves inference off by default for exactly this reason, and refuses to convert any value starting with a zero followed by a digit even when it is on.

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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