Is converting NDJSON to MySQL 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 MySQL?

Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real MySQL 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 MySQL

Upload a .json or .ndjson file and get back a MySQL SQL script you can load straight into your database. 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 MySQL

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

Your data	MySQL type
Whole number	BIGINT
Decimal (money)	DECIMAL(10,2)
Floating point	DOUBLE
True / false	TINYINT(1)
Date	DATE
Date and time	DATETIME
Short text	VARCHAR(255)
Long text	LONGTEXT
Binary data	LONGBLOB

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.

Loading the dump into MySQL

The download is a plain SQL script, so nothing in it depends on how you connect: the same file goes in through the command-line client, through a GUI import dialog or through phpMyAdmin. What is worth reading first is the handful of statements it runs before it creates anything.

→Before the first CREATE TABLE the script issues SET NAMES utf8mb4, so the session decodes the file as UTF-8 whatever the client's own default character set is. The file itself carries no marker saying so.
→The line after it turns FOREIGN_KEY_CHECKS off. That is there for the schema you are loading into, not for the script: it lets rows arrive in whatever order the tables came out of the source without a constraint that already exists rejecting them.
→A true/false column is declared TINYINT(1) and its values are written as 1 and 0. MySQL's own BOOLEAN keyword expands to exactly that, so a client that does not special-case the width shows you a number rather than 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 MySQL

→Tables are created as InnoDB with utf8mb4, so emoji and CJK text survive the load.
→Backslashes are escaped, because MySQL treats them as escape characters by default.
→Text columns of unknown length become TEXT rather than a guessed VARCHAR that could truncate your data.
→Inserts are batched, and identifiers are capped at MySQL’s 64-character limit.

What you get

A ZIP containing dump.sql, plus a README with the exact command to load it. If anything about your data needed a judgement call, a _warnings.txt explains it.

Load this dump into MySQL or MariaDB:

  mysql -u USER -p DATABASE < dump.sql

Create the database first if it does not exist:

  mysql -u USER -p -e "CREATE DATABASE DATABASE CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;"

Questions

Is converting NDJSON to MySQL 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 MySQL?: Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real MySQL 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.