Runs entirely client-side

Developer tools that run in your browser

No accounts, no uploads, no server round-trip. Every tool below works offline once the page has loaded.

JSON Viewer
Format, validate and explore JSON with collapsible nodes and key statistics.
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JSON ⇄ JSONL
Convert a JSON array to newline-delimited JSONL and back, ready for data pipelines.
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Base64 Encoder / Decoder
Encode text to Base64 or decode it back, with UTF-8 handled correctly.
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URL Encoder / Decoder
Percent-encode and decode URLs and query strings without mangling special characters.
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Date Calculator
Count the days between two dates, with optional business-day-only counting.
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