{}

Developer

JSON, regex, encoders, formatters — utilities for everyday coding.

20 tools · sorted by popularity

The developer tools are for the small, everyday jobs of writing and shipping code: formatting and validating JSON, XML, HTML, CSS, JavaScript, and SQL; encoding and decoding Base64, URLs, and HTML entities; testing regular expressions; decoding JWTs; calculating subnets; generating UUIDs and .gitignore files; building cron expressions and UTM links. They are the kind of tasks every developer does several times a day, and that usually live in a half-remembered command, a forgotten browser tab, or an online tool that uploads your input to a server you cannot audit.

Every developer tool here runs in your browser. Pasting a JWT, a JSON payload from production, a private API response, or a config file with secrets in it stays on your machine — never uploaded, never logged, never seen by a third party. That matters even more for development utilities than for ordinary tools, because the inputs are routinely things you are not supposed to share.

JSON Formatter & Validator

Paste JSON to format, validate, or minify — runs entirely in your browser.

Base64 Encoder / Decoder

Encode to Base64 or decode it back — handles UTF-8 correctly.

JSON ↔ CSV Converter

Convert between JSON and CSV — round-trip safe, runs locally.

Build and test JavaScript regular expressions with live highlighting.

UUID / GUID Generator

Generate cryptographically random UUID v4 identifiers.

Number Base Converter

Convert a number between binary, octal, decimal, hex, and any base 2–36.

JSON ↔ YAML Converter

Switch between JSON and YAML — useful for Kubernetes, CI configs, and API specs.

Paste a JWT to inspect its header and payload. Decoded locally.

Markdown ↔ HTML Converter

Convert between Markdown and HTML, with a live rendered preview for Markdown.

UTM Link Builder

Add UTM parameters to a URL to track campaigns in Google Analytics and other tools.

Subnet / CIDR Calculator

Enter an IPv4 address and CIDR prefix to get the full subnet breakdown.

HTML Entity Encoder / Decoder

Escape text to HTML entities, or decode entities back to characters.

HTML Formatter & Minifier

Beautify or minify HTML — useful for emails, snippets, and copy-pasted markup.

Make tangled SQL readable — supports common dialects.

Cron Expression Generator

Read cron expressions in plain English, with presets for common schedules.

URL Encoder / Decoder

Encode or decode URL components and query strings.

.gitignore Generator

Pick your stacks to get a sensible .gitignore.

XML Formatter & Validator

Pretty-print and validate XML.

CSS Formatter & Minifier

Format CSS with consistent indentation or strip it down for production.

JavaScript Formatter & Minifier

Format or minify JavaScript — handy for inspecting bundles or formatting snippets.

Other categories

¤Finance 13 ∑Math & Units 4 ◐Design 9 ▢Image 49 ¶Text 10 ⎘PDF 5 ✦Security 3 ⌛Date & Time 7 ≡Data 2