Developer Tools

Best Claude Code Skills 2026 - Curated Directory of AI Coding Skills

Browse AI coding skills, collections, and related projects by category. Compare repository information and check current instructions before use.

Free Online Tools - Developer & Utility Tools

Browser tools for CSV cleanup, JSON conversion, text, images and development. Compare examples, understand each tool’s limits, and work without signing up.

How to Compare Two Texts and Find the Difference

Compare two texts online to find every difference instantly. Learn line vs word diff, how diff algorithms work, and how to read a diff with real examples.

How to Convert a HEX Color to RGB (and HSL)

To convert a HEX color to RGB, split the 6 digits into three pairs and convert each pair from base-16 to decimal. Here's the math, examples, and a free tool.

How to Convert a Unix Timestamp to a Date

To convert a Unix timestamp to a date, multiply seconds by 1000 and feed it to a date function. Covers JS, Python, SQL, UTC vs local, ISO 8601, and 2038.

How to Count Words & Characters in Text Online

To count words and characters online, paste your text into a free word counter. It instantly shows words, characters, sentences, and reading time.

How to Encode and Decode Base64 Online (Free Guide)

Encode and decode Base64 instantly online: paste your text, click, and copy the result. Learn how Base64 works, URL-safe variants, and why it isn't encryption.

How to Format and Beautify JSON Online (Free)

To format JSON online, paste it into a free in-browser formatter and click Format. Learn to beautify, minify, validate, and fix JSON errors.

How to Generate a Strong, Secure Password (2026)

Generate a strong, secure password by using 16+ random characters or a 4-5 word passphrase. Learn the entropy math, password managers, 2FA, and how passwords get cracked.

How to Generate a UUID (v4, v1, v7) — Full Guide

Learn how to generate a UUID in seconds. Covers UUID versions (v4, v1, v7), collision odds, UUID vs auto-increment IDs, and code for JS, Python, and SQL.

How to Generate an MD5 or SHA-256 Hash Online

Generate an MD5, SHA-1, or SHA-256 hash online by pasting text or a file into a free in-browser tool. Learn the differences and how to verify checksums.

How to URL Encode and Decode a String

To URL encode a string, replace unsafe characters with percent-codes (a space becomes %20); to decode, reverse it. Here is exactly which characters to encode.

How to Install MCP Servers in Claude Code (Step-by-Step)

Install MCP servers in Claude Code in under 2 minutes with the claude mcp add command. Covers local, project, and user scopes, .mcp.json, remote servers, and troubleshooting.

How to Convert CSV to JSON Online Free

Learn how to convert CSV files to JSON format online for free. Step-by-step guide covering CSV format rules, common errors, and bulk conversion tips.

How to Decode a JWT Token (Without a Library)

Learn how to decode JWT tokens and understand their structure. Covers header, payload, signature, security tips, and common debugging techniques.

JavaScript Beautifier

Free JavaScript beautifier. Paste minified JS and get clean, formatted code with proper indentation. Choose 2-space, 4-space, or tab indent style.

Base64 Encoder & Decoder

Free Base64 encoder and decoder. Convert text to Base64 or decode Base64 strings instantly in your browser. Supports UTF-8 encoding and bulk input.

Chmod Calculator

Free chmod calculator for Unix file permissions. Toggle read, write, and execute for owner, group, and others to get the numeric chmod value instantly.

Crontab Expression Generator

Free crontab expression generator. Build cron schedules visually with human-readable descriptions and next run times. No signup required.

CSV to JSON Converter

Convert CSV to JSON with quoted fields, multiline values, and clear errors. Preserve leading zeros and long IDs as strings; review and download the result.

Hash Generator (SHA-1, SHA-256, SHA-512)

Generate SHA-1, SHA-256, and SHA-512 hashes from text using your browser’s local Web Crypto API. Compare digests without uploading the text.

How to Test Regex Online (with Live Matching & Debugging)

Learn how to test and debug regular expressions online. Covers common regex patterns, flags, capture groups, and real-time match highlighting.

HTML Entity Encoder & Decoder

Free HTML entity encoder and decoder. Convert special characters to HTML entities or decode entities back to text instantly in your browser.

HTTP Status Codes Reference

Free HTTP status codes reference. Searchable list of all HTTP response codes with descriptions, explanations, and common usage examples for developers.

JSON Formatter & Validator

Free JSON formatter and validator. Paste messy JSON and instantly format, validate, and beautify it with syntax highlighting and error line numbers.

JSON to CSV Converter

Convert JSON to CSV using keys from every record. Choose a nested-value policy, review formula-like text, and preserve identifiers as strings before export.

JSON to YAML Converter

Free JSON to YAML converter and vice versa. Paste JSON or YAML and get clean, readable output in the other format. Runs entirely in your browser.

JWT Token Decoder

Decode JWT headers and payloads locally in your browser. Inspect token fields without uploading the token; decoding does not verify its signature.

Markdown to HTML Preview

Free Markdown to HTML previewer. Write Markdown on the left and see rendered HTML in real time on the right. No signup, runs in your browser.

Regex Tester & Debugger

Free regex tester and debugger. Test regular expressions in real time with match highlighting, capture groups, and flag support. No signup needed.

Text Diff Checker

Free text diff checker. Compare two texts side by side with additions, deletions, and changes highlighted. Runs in your browser, no data uploaded.

Text to Binary Converter

Free text to binary converter. Convert text to binary code and binary back to text. Also supports HEX and octal conversions. No signup required.

Unix Timestamp Converter

Free Unix timestamp converter. Convert Unix epoch timestamps to human-readable dates and vice versa. Shows the current timestamp live. No signup needed.

URL Encoder & Decoder

Free URL encoder and decoder. Encode or decode URLs and query strings with full support for special characters and UTF-8. Runs in your browser.

UUID Generator (v4)

Free UUID v4 generator. Generate random UUIDs in bulk and copy one or many with a single click. No signup needed, runs entirely in your browser.