Is converting NDJSON to Excel free?

Yes. Files up to 10MB convert free with no account. There is a limit of five conversions per day per IP address.

Will my NDJSON data keep its types in Excel?

Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real Excel types rather than everything becoming text. The mapping table above shows exactly what you get.

Do you store my file?

No. The file is written to a temporary directory, converted, and the directory is deleted as soon as your download has been sent.

Convert NDJSON to Excel

Upload a .json or .ndjson file and get back a Excel file. Types are preserved rather than flattened to text. Free, no registration, up to 10MB.

1Upload your file

Click to upload or drag and drop

CSV, Excel, SQLite, SQL, DBF (max 10 MB)

2Choose target format

How your data is typed in Excel

Generated from the converter's own Excel type mapping — this is what it actually emits, not an example.

Your data	Excel type
Whole number	number
Decimal (money)	number
Floating point	number
True / false	boolean
Date	date
Date and time	date
Short text	text
Long text	text
Binary data	hex text

Working from an .ndjson file

Newline-delimited JSON is one complete object per line with no enclosing array, which is exactly what makes it appendable: a log or an export can keep growing without anything having to rewrite the end of the file.

→Each line is parsed on its own and blank lines are ignored, but a single malformed or truncated line fails the whole file - the usual outcome of copying a log that was still being written.
→Lines need not share their keys. The columns are what the records collectively use, and a record that omits one gets NULL in that column.
→A file that is one line long and wraps its array, {"rows": [...]}, is unwrapped into those rows rather than read as a single record.

What opens the converted workbook

Choosing Excel as the target puts no copy of Excel anywhere in the process: the workbook is assembled on the server by a library and handed over finished. What that library writes is what decides how the result behaves when you open it.

→The output is .xlsx, the OOXML format, and only that. There is no .xls option, so a machine that can open nothing newer than Excel 97-2003 needs the CSV target and a save from there instead.
→Values are the only thing written. No formulas, no macros, no charts, no column widths, no frozen header row - which is why the first thing most people do with it is widen a column. If Excel opens it in Protected View, that is the mark of the web on a downloaded file rather than anything in the workbook.
→A conversion is capped at a million rows across all of its tables, and a worksheet holds 1,048,576, so no table can ever arrive too tall for the sheet it is being written into.

Reading NDJSON

→JSON types are trusted: 1 and "1" stay different things.
→Numbers with a decimal point are read as exact decimals rather than floats.
→Both an array of objects and newline-delimited JSON work, and a wrapped array like {"data": [...]} is unwrapped automatically.
→Nested objects are kept as JSON rather than flattened into invented column names.

Writing Excel

→One file per table. Booleans stay booleans and numbers stay numbers.
→Excel has no fixed-point type, so decimals become numbers — use a database target if exactness matters.

What you get

A ZIP containing <table>.xlsx. If anything about your data needed a judgement call, a _warnings.txt explains it.

Questions

Is converting NDJSON to Excel free?: Yes. Files up to 10MB convert free with no account. There is a limit of five conversions per day per IP address.
Will my NDJSON data keep its types in Excel?: Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real Excel types rather than everything becoming text. The mapping table above shows exactly what you get.
Do you store my file?: No. The file is written to a temporary directory, converted, and the directory is deleted as soon as your download has been sent.