JSONL ↔ JSON Converter
Convert JSON Lines to a JSON array and back again.
JSONL input
Drop a file here
Drop a .jsonl or .json file
JSON output
About the JSONL ↔ JSON Converter
Turn a JSONL / NDJSON file into a proper JSON array for tools that expect one, or flatten a JSON array (optionally nested under a key) back into streaming JSON Lines for fine-tuning, BigQuery or log pipelines.
Examples
JSONL to array
{"id":1}
{"id":2}Output
[
{ "id": 1 },
{ "id": 2 }
]Keyboard shortcuts
- Copy the main outputCtrl / ⌘ + Shift + C
- Download the resultCtrl / ⌘ + S
- Share this toolCtrl / ⌘ + Shift + S
- Reset the inputsAlt + R
- Open the tool search paletteCtrl / ⌘ + K
Related tools
JSONL Formatter
AI & LLM
Pretty-print, minify, sort and deduplicate JSON Lines files.
JSONL Validator
AI & LLM
Validate JSONL and fine-tuning datasets line by line.
AI PII & Secret Redactor
AI & LLM
Strip emails, keys, tokens and personal data before prompting an LLM.
AI Token Counter
AI & LLM
Count exact LLM tokens for GPT, Claude and Gemini prompts.
AI Tool Schema Builder
AI & LLM
Build function-calling schemas for OpenAI, Claude, Gemini, MCP and the AI SDK.
LLM API Cost Calculator
AI & LLM
Estimate GPT, Claude and Gemini API spend per call and per month.
Frequently asked questions
Version 1.0.0 · Updated 2026-08-14 · Runs entirely in your browser