Code Generators

.htaccess Generator

Build an Apache .htaccess from toggles for HTTPS, caching, headers and more.

ASCII Table

All 128 ASCII codes in decimal, hex, octal and binary.

Base Converter

Convert numbers between binary, octal, decimal and hex.

Base64 Encoder / Decoder

Encode and decode Base64, standard or URL-safe.

Bcrypt Cost Benchmark

Time bcrypt cost factors and pick one that fits your login budget.

Border Radius Generator

Per-corner border-radius with shorthand and longhand output.

Browser Detector

See your browser, OS, screen and supported features at a glance.

Cache-Control Header Builder

Build a Cache-Control header and see exactly how browsers and CDNs will treat it.

CHMOD Calculator

Convert Unix permissions between rwx, octal and symbolic.

Chmod Cheat Sheet

Permission digits, common modes and special bits on one page.

Code Line Counter

Count code, comment and blank lines in a source file.

Config Generator

Turn key = value lines into .env, JSON, YAML, TOML or INI files.

Context Window Calculator

Check whether a prompt, documents and reply fit a model's context window.

Cookie Parser

Break Set-Cookie and Cookie headers into readable attributes with warnings.

Copy To Clipboard Button Generator

Copy to clipboard button for code blocks, inputs or fixed text.

Core Web Vitals Calculator

Check whether your page passes Core Web Vitals and which metric to fix first.

Corner Ribbon Maker

Diagonal corner ribbons for cards, no images required.

Cron Cheat Sheet

Crontab fields, operators and ready-made schedule expressions.

Cron Expression Builder

Build a cron schedule and see when it actually runs.

CSS Border Generator

Build a border shorthand with any style, side and radius.

CSS Formatter

Expand minified CSS to one declaration per line, or minify it back.

CSS Generator

Build a formatted CSS rule from a selector and a form of properties.

CSS Selector Tester

Test a CSS selector against pasted HTML and list every matching element.

CSS Shapes Generator

Classic single-element CSS shapes with size and colour controls.

CSS Size Calculator

Measure a stylesheet's real transfer size and see whether it blocks first paint.

CSS Validator

Find typos, missing semicolons and unknown properties in pasted CSS.

CSV / JSON Converter

Convert CSV to JSON and back, quoting handled properly.

CSV Column Extractor

Keep, drop and reorder columns in CSV data.

CSV Formatter

Align CSV into readable columns or swap delimiters and fix quoting.

CURL Converter

Turn a curl command into code in 24 languages.

DNS Lookup

Query any DNS record for a domain with TTLs and explanations.

Email DNS Record Checker

Check an SPF, DKIM or DMARC record before you publish it.

Email Validator

Check a list of email addresses for syntax errors and likely typos.

Epoch Converter

Convert Unix timestamps to dates and back again.

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ER Diagram Maker

Type tables and relationships to draw a crow's foot ER diagram.

Git Cheat Sheet

Find the right git command and whether it is safe to run.

Git Secret Removal Guide

Step-by-step commands to purge a leaked secret from git history.

Gzip / Brotli Size Comparison

Compare what gzip and Brotli save on a real file.

HTML Email Button Generator

Bulletproof email buttons with inline styles and an Outlook VML fallback.

HTML Entity Encoder

Escape and unescape HTML entities in any text.

HTML Formatter

Indent messy HTML or collapse it safely, keeping pre and script intact.

HTML Generator

Generate a complete HTML5 boilerplate page from a short form.

HTML Validator

Find unclosed tags, duplicate ids and bad nesting in pasted HTML.

HTTP Status Codes

Look up what any HTTP status code actually means.

Image Size Calculator

Estimate image file size and see how oversized it is for its slot.

Indent Code

Shift every line right by a set number of spaces or tabs.

IP Address Info

Classify any IPv4 or IPv6 address and see its every form.

IP Subnet Calculator

Network, broadcast, host range and counts for any subnet.

JavaScript Deobfuscation Helper

Decode hidden strings in obfuscated JavaScript and flag risky calls safely.

JavaScript Formatter

Expand minified JavaScript into indented code, or squash it back.

JavaScript Size Calculator

See what a script bundle costs to download and to parse on a phone.

JSON Diff

Compare two JSON documents and list every change by path.

JSON Formatter

Format, minify and validate JSON, with located errors.

JSON Generator

Generate realistic mock JSON records from a simple name and type list.

JSON To YAML Converter

Convert JSON to YAML and YAML back to JSON.

JSON Tree Viewer

Browse JSON as a collapsible tree with the path to every value.

JSONPath Tester

Run JSONPath queries against pasted JSON and see every match.

Keycode Tester

Press a key and see exactly what your browser reports.

Lighthouse Score Explainer

See exactly where your Lighthouse performance score comes from.

Line Ending Converter

Convert text between LF, CRLF and CR line endings instantly.

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Mermaid Live Editor

Type Mermaid syntax, preview it live and download SVG or PNG.

MIME Type Lookup

Look up the MIME type for an extension, or the reverse.

OWASP Top 10 Reference

The OWASP Top 10 web risks with plain explanations and fixes.

Page Weight Calculator

Add up page resources, see the breakdown and load time on each connection.

Password Hash Generator

Argon2id, scrypt and PBKDF2 password hashes with OWASP defaults.

Performance Budget Calculator

Turn a load-time target into a byte budget for each part of the page.

Print Button Generator

Print this page button with print CSS for one section or all.

RAG Chunk Calculator

Plan chunk size and overlap for retrieval-augmented generation.

Reading Progress Bar

Make a scroll progress bar for articles and copy the CSS and JS.

Regex Cheat Sheet

Regular expression syntax with examples, printable and downloadable.

Regex Generator

Build a regex from a preset or from sample strings, ready to paste.

Regex Search And Replace

Bulk find and replace with regular expressions.

Regex Tester

Test a regex and see every match and capture group.

Resource Hint Generator

Generate correct preconnect, preload and prefetch tags with the right attributes.

Responsive Iframe Generator

Responsive iframe embed code for YouTube, Vimeo, maps and more.

Responsive Image Generator

Generate srcset, sizes and picture markup for responsive images.

Secret Scanner

Find leaked API keys, tokens and passwords in pasted code.

Security Headers Generator

Generate HTTP security headers for nginx, Apache, Netlify and Express.

SemVer Tool

Sort, compare and bump semantic version numbers.

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Sequence Diagram Maker

Type A -> B message lines and get a sequence diagram.

Share Button Builder

Social share buttons for nine networks, with no tracking scripts.

SQL Formatter

Turn a one-line SQL query into readable indented SQL.

SRT / VTT Converter

Convert SRT subtitles to WebVTT and back, with an optional time shift.

String Escaper

Turn raw text into a safe string literal in any language.

String Unescaper

Decode backslash escapes and quoted literals back into plain text.

SVG Validator

Find unclosed tags, bad path data and broken references in SVG.

Text To Hex Converter

Convert text to hexadecimal bytes and back again.

Unindent Code

Remove common or fixed indentation from a block of code.

URL Encoder / Decoder

Percent-encode and decode URLs, values and form data.

URL Query Parser

Split a URL into a readable table of parameters.

URL Validator

Check a list of URLs for syntax errors, one per line.

User Agent Parser

See what browser and OS a User-Agent string claims to be.

Web App Manifest Generator

Generate a PWA manifest.webmanifest with icons, colours and head tags.

Webhook Payload Viewer

Flatten any JSON webhook payload into searchable paths and values.

XML Formatter

Indent messy XML or squash it to one line, with tag checking.

XML To JSON Converter

Convert XML to JSON and JSON back to XML.

XPath Tester

Test XPath expressions against pasted XML or HTML instantly.

YAML Formatter

Tidy inconsistent YAML and pinpoint syntax errors by line.