Tool World
Developer Tools
Free online Developer tools on Tool World. Browse every Developer utility by subcategory — no signup required.
Encoding
Base64 Decode
Decode Base64 to text. Processed in your browser.
Base64 Encode
Encode text to Base64. Processed in your browser.
HTML Decoder
Unescape HTML entities back into plain characters.
HTML Encoder
Escape HTML special characters so markup displays as text.
URL Decode
Decode percent-encoded URLs. Processed in your browser.
URL Encode
Percent-encode URLs and query strings. Processed in your browser.
Unicode Inspector
Inspect Unicode code points, encodings, blocks, and categories.
Formatters
CSS Beautifier
Format and indent minified or messy CSS.
JavaScript Beautifier
Beautify and indent JavaScript source.
Minify
CSS Minifier
Minify CSS stylesheets for smaller file size.
HTML Minifier
Minify HTML by removing comments and extra whitespace.
JavaScript Minifier
Minify JavaScript with terser (compress + mangle).
JSON
CSV to JSON
Convert CSV tables to JSON. Processed in your browser.
JSON Formatter
Pretty-print and format JSON. Processed in your browser.
JSON Minifier
Minify JSON for production. Processed in your browser.
JSON Validator
Validate JSON and show errors. Processed in your browser.
JSON to CSV
Convert JSON arrays to CSV. Processed in your browser.
JSON to XML
Convert JSON to XML. Processed in your browser.
JSON to YAML
Convert JSON to YAML. Processed in your browser.
YAML to JSON
Convert YAML to JSON. Processed in your browser.
Converters
Color Converter
Convert colors between HEX, RGB, and HSL.
HTML to Markdown
Convert HTML markup to Markdown in your browser.
Markdown to HTML
Convert Markdown to clean HTML locally.
Number Base Converter
Convert between binary, octal, decimal, and hexadecimal.
Query String Builder
Build URL query strings from key/value pairs.
Query String Parser
Parse URLs into JSON and build query strings.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates.
Generators
Cron Expression Generator
Build cron expressions from presets and field selectors.
Lorem Ipsum Generator
Generate placeholder paragraphs, sentences, or words.
UUID Generator
Generate UUID v4 identifiers in your browser.
Testers
Cron Expression Validator
Validate a 5-field cron expression and preview upcoming runs.
Cron Parser
Explain cron expressions and show the next run times.
Regex Explainer
Break down a regular expression into readable token explanations.
Regex Generator
Generate common regex patterns (email, URL, UUID, and more).
Regex Tester
Test regular expressions against sample text live.
Text Diff
Compare two texts line by line and highlight changes.
Security
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes.
Auth
JWT Debugger
Decode, inspect, verify HS* signatures, and rebuild JSON Web Tokens.
JWT Decoder
Decode and inspect JWT header and payload locally.
JWT Encoder
Build unsigned JWTs (alg: none) for local testing.
JWT Generator
Generate signed HS* JWTs (or unsigned) from header and payload JSON.
JWT Validator
Validate JWT structure, expiry claims, and optional HMAC signatures.
Web
MIME Type Lookup
Look up MIME types from file extensions and vice versa.
URL Builder
Compose a full URL from protocol, host, path, query, and hash.
URL Parser
Parse a URL into protocol, host, path, query parameters, and more.
XML Formatter
Pretty-print XML documents. Processed in your browser.
XML Validator
Validate XML structure. Processed in your browser.
Preview
Markdown Preview
Preview Markdown as formatted HTML.
HTTP
cURL Generator
Generate a cURL command from method, URL, headers, and body.
cURL to Code
Convert a cURL command into fetch, Axios, or Python requests code.