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Dev Utilities

Developer utilities

41 tools, no ads, no accounts, no telemetry. Every conversion runs in your browser, so nothing you paste leaves this machine. Press ⌘K to jump to a tool.

Convert

JSON ↔ YAML

Convert between JSON and YAML in either direction

CSV ↔ JSON

Convert delimited data to JSON records and back

Code formatter

Pretty-print, minify and validate JSON, XML and SQL

JSON to TypeScript

Generate TypeScript interfaces from a JSON sample

curl to code

Turn a curl command into fetch, Python, Go or PowerShell

JSON to elmer keys

Turn a JSON object into elmer key set, key get or dep key commands

Query params to JSON

Split a query string into structured JSON and back

Number base converter

Convert between binary, octal, decimal, hex and any base to 36

Timestamp converter

Convert between Unix epochs, Epic DAT, DTE and Instant values, and dates in any time zone

Encode & decode

Base64 encoder

Encode and decode Base64, with UTF-8 and URL-safe handling

URL encoder

Percent-encode and decode URLs and query components

HTML entity encoder

Escape and unescape HTML entities

Backslash escape

Escape and unescape string literals for code and config

Inspect

JWT decoder

Read a JWT's claims and verify its signature against a key you paste

Regex tester

Test a regular expression against sample text with match highlighting

Diff checker

Compare two blocks of text line by line

Cron parser

Explain a cron expression and preview its next runs

HAR file viewer

Inspect requests, timings and headers in a HAR capture

User agent parser

Break a user agent string into browser, OS and device

Generate

Hash generator

Compute SHA-1, SHA-256, SHA-384 and SHA-512 digests

UUID generator

Generate v4 and v7 UUIDs in bulk

Password generator

Generate strong random passwords and passphrases

JWT generator

Build and sign a JWT with an HMAC secret

QR code generator

Turn text or a URL into a downloadable QR code

Lorem ipsum

Generate placeholder paragraphs, sentences and words

Text

Case converter

Convert between camel, snake, kebab, pascal and title case

Slugify

Turn any text into a URL-safe slug

Text sorter

Sort, reverse, shuffle and dedupe lines

Whitespace remover

Strip trailing, leading and duplicate whitespace

Character counter

Count characters, words, lines and bytes

Markdown preview

Render Markdown to HTML side by side

HTML to Markdown

Convert an HTML fragment into Markdown

Image

Image to Base64

Turn an image into a Base64 data URI

Base64 to image

Decode a Base64 data URI back into a downloadable image

WebP converter

Convert PNG and JPEG images to WebP in the browser

Image resizer

Resize and crop images without uploading them

SVG optimizer

Strip metadata and shrink SVG markup

Favicon generator

Produce a favicon set from a single source image

Color

Color converter

Convert between hex, RGB, HSL and OKLCH

Contrast checker

Check colour pairs against WCAG contrast thresholds

Gradient generator

Build CSS gradients and copy the declaration

Network

What is my IP

Your public IP, IPv4 or IPv6, and the edge that served you

Planned

This needs to reach a server, and this site's connect-src is'self' with no exceptions — which is what lets every tool above promise that nothing you paste leaves the tab. Building it means trading that away first, so it stays here on purpose rather than for want of the work.

DNS lookup

Resolve A, AAAA, MX, TXT and CNAME records