Convert NDJSON to SQLite3
Upload a .json or .ndjson file and get back a SQLite3 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 SQLite3
Generated from the converter's own SQLite3 type mapping — this is what it actually emits, not an example.
| Your data | SQLite3 type |
|---|---|
| Whole number | BIGINT |
| Decimal (money) | NUMERIC(10,2) |
| Floating point | REAL |
| True / false | BOOLEAN |
| Date | DATE |
| Date and time | TIMESTAMP |
| Short text | TEXT |
| Long text | TEXT |
| Binary data | BLOB |
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 .sqlite3 name and what carries over
The 3 in sqlite3 is the file format version and the name of the command-line tool, not a property of your conversion. One database file arrives, and the two things worth knowing about it are what it is called and what it leaves behind.
- →The file inside the zip is always database.sqlite, whichever spelling brought you to this page. Rename it to database.sqlite3, or to whatever a framework expects, once you have it - the header is what identifies it, never the extension.
- →An auto-increment column arrives holding all of its values and nothing that assigns new ones. No AUTOINCREMENT keyword is written, and the column is declared BIGINT rather than exactly INTEGER, so it is not an alias for the rowid either: rows you insert later have to supply their own key.
- →Only the rows are transactional. The very first CREATE TABLE runs in autocommit, and everything after it - that table's rows, and every later table - sits in one transaction that commits after the last row. A conversion that fails partway therefore leaves a file holding an empty shell of the first table and nothing else. You never receive that file: the zip is only assembled once the writer has returned.
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 SQLite3
- →Columns get real declared types rather than everything being TEXT.
- →Primary keys and NOT NULL constraints are preserved.
- →A money column is declared NUMERIC(10,2), but that declaration does not stop SQLite’s own numeric affinity from converting the inserted value into a float once it lands, so 19.99 can come back with a rounding tail. Pick the DuckDB target instead when the exact decimal has to survive.
What you get
A ZIP containing database.sqlite. If anything about your data needed a judgement call, a _warnings.txt explains it.
Questions
- Is converting NDJSON to SQLite3 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 SQLite3?
- Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real SQLite3 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.