Turn TOML files into NDJSON
Drop in a TOML and get an NDJSON back. NDJSON puts one complete record on each line, so a program can start working through a huge file immediately instead of waiting for all of it. Your file never leaves your computer.
Need the other direction? Convert NDJSON to TOML
How to convert TOML to NDJSON
- 1 Drop your TOML .toml file onto the page, or click to browse for it.
- 2 Check the options. Nothing is thrown away on the way to NDJSON, so there is no quality dial to set.
- 3 Convert. The work happens on your own machine, so how long it takes depends on your computer and the file.
- 4 Download the NDJSON, or add more files and do the whole set in one go.
Why convert TOML to NDJSON
- Constant memory processing regardless of how large the file grows.
- New records can be appended without rewriting the file.
- Bulk index and export operations in Elasticsearch and BigQuery.
- TOML: deeply nested settings get awkward and long-winded.
TOML compared with NDJSON
How the two formats differ on the things that decide whether a conversion is worth making.
| Property | TOML | NDJSON |
|---|---|---|
| File extension | .toml | .ndjson |
| Colour depth | UTF-8 key-value text with tables, arrays and native date types | One JSON value per line, UTF-8, no wrapping array |
| Developed by | Tom Preston-Werner | Community convention, also known as JSON Lines |
Quality and what changes
Both sides are lossless, so every pixel survives the trip intact and converting back returns the same image. What changes is the size and what the file can carry: NDJSON stores the data without compression, so expect a much larger file.
- One NDJSON limitation to keep in mind: not valid JSON as a whole, so generic JSON tooling rejects it.
Questions about TOML to NDJSON
Can I open an NDJSON in a browser?
No. No mainstream browser renders NDJSON natively, so it will download rather than display. That is fine when the file is heading into desktop software or an archive, and a problem if it is going on a web page.
Is my TOML file uploaded anywhere?
No. The whole thing runs inside the browser tab you already have open. Your TOML is read straight from your own disk, converted on your machine and handed back as an NDJSON. Nothing is sent anywhere, nothing is stored and there is no account.
Is there a file size limit?
There is no server-side limit because no server sees the file. The real ceiling is your device memory, since the input and the output both have to fit in the tab. A few hundred megabytes is usually fine on a desktop machine and considerably less on a phone.
Can I convert several TOML files at once?
Yes. Add as many as you like and they are processed one after another, then offered as separate NDJSON downloads or as a single ZIP. Speed depends on your own processor rather than on a queue.
Does the converter work offline?
Yes, after the page has loaded once. The engine is cached by the browser, so you can disconnect, reload and keep converting. That falls out of doing the work locally rather than being a separate mode you switch on.