Tablizer

Convert JSON to AsciiDoc Online

Paste a JSON table below, edit it if you need to, and get AsciiDoc 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 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 AsciiDoc is

AsciiDoc tables are delimited by |=== and take a cols attribute describing the columns.

Antora documentation sites, and technical writing teams that outgrew Markdown.

What changes when you convert JSON to AsciiDoc

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.

The header option is set so the first row renders as a header row rather than data.

What carries over from JSON to AsciiDoc

JSON records 2 things about a table that AsciiDoc has no way to hold.

JSON distinguishes a number from the text of a number; AsciiDoc does not, so every value arrives as text and has to be re-parsed by whatever reads it next.

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

AsciiDoc marks header cells differently from data cells, so the keys are lifted out and written once as a marked header row rather than repeated on every row.

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

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

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" }
]
AsciiDoc out
[cols="1,1,1,1,1",options="header"]
|===
| id | name | role | started | hours
| 007 | Halima Yusuf | Analyst, data | 2024-03-15 | 38.5
| 012 | Jonah "Jo" Pryce | Engineer | 2025-11-02 | 
| 104 | Wei Chen | Manager | 2023-06-30 | 40
|===

Questions

How do I convert JSON to AsciiDoc?

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

Will my numbers still be numbers?

They will read the same, but AsciiDoc stores them as text. Anything that sorts or sums the result will need to parse them first, and a leading zero or a currency symbol is the usual place that goes wrong.

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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