Utileno
EN한국어
DEV

Developer tools

The things a task needs for a minute and then forgets: a JSON formatter that indents an API response and points at the parse error, a URL encoder that percent-encodes non-ASCII text, a hash generator that checks a download against its published checksum, a timestamp converter that reads a number like 1700000000 from a log, a UUID generator for a key the client can make itself, and a punycode converter for domains written in letters DNS cannot carry.

They all run entirely in your browser, so a response containing tokens or personal data can be pasted without it being sent anywhere. The category grows only when there is a real problem to solve.

12 tools

Start here

JSON Formatter & ValidatorFormat, validate and minify JSON without uploading it — your data stays in your browser.

ExampleDebug an API response — Paste a one-line API response and click Format — nested objects and arrays become readable with proper indentation.

Unix Timestamp ConverterPaste an epoch timestamp to get local, UTC and ISO dates — or pick a date to get its timestamp.

ExampleDecode a log entry — A log shows 1755302400. Paste it to see it is 2025-08-16 00:00:00 UTC — and what that was in your local time zone.

Data formats

JSON Formatter & ValidatorFormat, validate and minify JSON without uploading it — your data stays in your browser.CSV ↔ JSON ConverterPaste a spreadsheet, take JSON — or the other way round.

Regular expressions

Regex TesterType a pattern and see what it catches.

HTML meta tags

Meta Tag GeneratorFill the boxes, take the head tags.

Time values

Unix Timestamp ConverterPaste an epoch timestamp to get local, UTC and ISO dates — or pick a date to get its timestamp.Cron Expression ExplainerReads a cron line in plain words and lists the next run times.

URLs and encoding

URL Encoder / DecoderPercent-encoding both ways, with the encodeURIComponent and encodeURI difference shown.Base64 Encoder & DecoderText and files to Base64 and back, safe for any language.

Hashes and checksums

Hash GeneratorText or file, four algorithms at once, nothing uploaded.

Number bases

Number Base ConverterBinary, octal, decimal and hex both ways, with the working shown.

Identifiers

UUID GeneratorVersion 4, from the browser random source. Nothing is sent or stored.

Domain names

Punycode ConverterDomains with letters DNS cannot carry, and the xn-- form that it can.

Recently added

Related categories