Tablizer

Convert JSON Lines to Excel Online

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

JSON Lines is one complete JSON object per line, with no enclosing array and no commas between records. The file is not valid JSON as a whole, and that is the point.

Log pipelines, machine learning datasets and anything that appends records or reads them in a stream.

What Excel is

An Excel workbook is a zip archive of XML parts describing sheets, cells, formulas, styles and charts. The .xlsx extension is that format; .xls is the older binary one from before 2007.

Finance, operations and anyone who received a file from finance or operations.

What changes when you convert JSON Lines to Excel

Each line is parsed on its own, so a corrupt record does not take the file with it. Keys are unioned across lines in first-seen order, so a record missing a field leaves that cell empty rather than shifting the columns.

You get a single sheet with a header row and column widths sized to the content. Values are written as text unless type inference is on, which keeps identifiers like 0044 or 007 intact.

What carries over from JSON Lines to Excel

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

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

The keys stop being repeated: Excel writes the column names once at the top, so the same table takes noticeably less space.

JSON Lines can be read one record at a time. Excel has to be complete before it means anything, so the whole table is held in memory while it is written and a file that gets cut off part way through is not partly usable - it is unusable.

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

Questions

How do I convert JSON Lines to Excel?

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

What is the difference between JSON and JSON Lines?

JSON wraps records in an array, so a reader must load the whole document before it can use any of it, and appending means rewriting the file. JSON Lines has no wrapper, so records can be streamed and appended one at a time. Use JSON for a payload, JSON Lines for a log.

Does converting to Excel keep my formulas?

No. A table has values, not formulas. If your source came from Excel in the first place, the formulas were already resolved to their results before they reached this page. Anything that was =SUM(A1:A10) arrives as the number it produced.

What happens to nested values?

Excel has no nested cell, so a list or object inside a JSON Lines 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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