NISI Tools collection
Useful browser tools, built to stay out of your way.
Every tool runs at tools.nisi.ro. They are free, work without an account, and process your input locally wherever practical.
Developer
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JSON Formatter & Validator
Format, validate, beautify and minify JSON.
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Regex Tester
Test regular expressions with live match highlighting.
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Base64 Encoder & Decoder
Convert UTF-8 text and files to and from Base64.
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URL Encoder & Decoder
Encode URLs and inspect query-string values.
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Unix Timestamp Converter
Convert epoch timestamps to readable local and UTC dates.
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UUID Generator & Validator
Create UUID v4 values in bulk and validate UUIDs.
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Markdown Editor & Previewer
Write Markdown with a live preview and HTML export.
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JWT Decoder
Read JWT headers and payloads locally in your browser.