Convert NDJSON to CSV
Upload a .json or .ndjson file and get back a CSV file. Types are preserved rather than flattened to text. Free, no registration, up to 10MB.
Click to upload or drag and drop
CSV, Excel, SQLite, SQL, DBF (max 10 MB)
How your data is typed in CSV
Generated from the converter's own CSV type mapping — this is what it actually emits, not an example.
| Your data | CSV type |
|---|---|
| Whole number | text (CSV has no types) |
| Decimal (money) | text (CSV has no types) |
| Floating point | text (CSV has no types) |
| True / false | text (CSV has no types) |
| Date | text (CSV has no types) |
| Date and time | text (CSV has no types) |
| Short text | text (CSV has no types) |
| Long text | text (CSV has no types) |
| Binary data | text (CSV has no types) |
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.
The shape of the CSV files you get
CSV is where the type information stops, so what is left to describe is the file itself: how a row is terminated, which fields are quoted, and how a value that used to have a type is spelled out as characters.
- →Rows end with a carriage return and a line feed, the RFC 4180 ending, while a newline inside a quoted field stays the single character it always was. The encoding is UTF-8 with no byte-order mark in front of it.
- →Quotes go on only where they are needed - a field holding a comma, a double quote or a newline - and a quote inside a field is doubled rather than escaped with a backslash. Every other field is written bare.
- →Decimal values are written digit for digit and never through a floating-point number, so a money column that was exact in the source is still exact in the file. Booleans are written lower case, as true and false, which is the spelling this converter's own reader takes back as a boolean.
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 CSV
- →One file per table, with a header row.
- →NULL is written as an empty field, never the word "None".
- →Binary data is written as hex, which is reversible.
What you get
A ZIP containing <table>.csv. If anything about your data needed a judgement call, a _warnings.txt explains it.
Questions
- Is converting NDJSON to CSV 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 CSV?
- Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real CSV 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.