TONL is a compact, line-oriented notation for tabular and structured data, designed to use fewer tokens than JSON when included in LLM prompts.

Does my CSV need a header row?

It works either way. Toggle 'First Row Header' so the converter knows whether the first line names the columns.

Can I use a different delimiter?

Yes. Set the CSV delimiter (comma, semicolon, tab, etc.) to match your file, and pick a separate delimiter for the TONL output.

No. Conversion is done locally in your browser, so your CSV stays on your device.

CSV to TONL Converter

Convert CSV to TONL online — turn spreadsheets and exports into compact, token-efficient TONL for LLM prompts. Free and browser-based.

Options

Input Settings

Format

CSV delimiter

CSV options

TONL Settings

Encoding

TONL delimiter

Indent

Input

TONL Output

About CSV to TONL Converter

Paste CSV — a spreadsheet export, a database dump, a report — and convert it to TONL, a compact line-oriented notation built for fitting tabular data into LLM prompts. Conversion runs in your browser with a live token-savings estimate.

TONL keeps rows readable while stripping the overhead you would pay encoding the same table as JSON. Tune the CSV delimiter, header handling, and TONL encoding options to match your data.

How to use CSV to TONL Converter

Paste your CSV
Paste CSV into the input editor (an example is preloaded).
Set input options
Pick the CSV delimiter and whether the first row is a header.
Convert
Click Convert → TONL to generate the output and see token savings.
Copy the TONL
Copy the result for use in your prompt or pipeline.

Frequently asked questions

CSV / JSON → TONL Converter

The full converter with both input formats.

JSON to TONL Converter

Convert JSON instead of CSV.

Looking for the full tool? Open the complete converter.