Is converting JSON 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 JSON 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 JSON 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 a .json file

A .json file can be almost any shape, and only a few of those shapes are a table. What the reader accepts, and what it does with the rest, is the thing worth knowing before you upload one.

→A wrapper is unwrapped only when the object has exactly one key and that key holds a list of objects. {"meta": {...}, "data": [...]} has two keys, so it is read as a single row instead.
→An array of strings, or an array of arrays, is refused with "Expected a JSON array of objects" - there are no column names in it to build a table from.
→Columns are the union of the keys seen in the first 10,000 records, in the order they first appear. A key that shows up only after that is not part of the table.

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 JSON

→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 JSON 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 JSON 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.