What kind of JSON works best for TONL?

Arrays of uniform objects (records with the same keys) compress best, because TONL declares the field structure once instead of repeating keys on every row.

How much does TONL save versus JSON?

It varies with structure, but uniform tabular data commonly drops a meaningful share of tokens. The tool shows the exact estimate for your input.

Is the conversion lossless?

TONL is designed to represent the same structured data compactly. For LLM-prompt use the goal is faithful, readable structure at a lower token cost.

Does this send my JSON anywhere?

No. Everything runs locally in your browser; your JSON is never uploaded.

JSON to TONL Converter

Convert JSON to TONL online — turn JSON arrays and objects into compact, token-efficient TONL for LLM prompts. Free and browser-based.

Options

Input Settings

Format

TONL Settings

Encoding

TONL delimiter

Indent

Input

TONL Output

About JSON to TONL Converter

Paste JSON and convert it to TONL, a compact line-oriented notation built to fit structured data into LLM prompts with fewer tokens than JSON. The conversion runs in your browser and shows the estimated token savings.

JSON to TONL is ideal when you are feeding arrays of records — users, events, rows — into a model and want to preserve structure while trimming token cost. Tune the TONL encoding and delimiter to fit your data.

How to use JSON to TONL Converter

Paste your JSON
Paste JSON into the input editor (an example is preloaded).
Set TONL options
Choose smart encoding, type hints, delimiter, and indentation.
Convert
Click Convert → TONL to generate the output and see token savings.
Copy the TONL
Copy the result for your prompt or pipeline.

Frequently asked questions

CSV / JSON → TONL Converter

The full converter with both input formats.

CSV to TONL Converter

Convert CSV instead of JSON.

Looking for the full tool? Open the complete converter.

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