Free Developer Tools
Browser-based utilities for formatting data, decoding tokens, testing patterns, comparing text, and debugging everyday development tasks.
Popular tools
JSON Formatter & Validator
Format, validate, and beautify JSON data instantly. Paste messy JSON and get clean, indented output.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text. Fast, free, and runs entirely in your browser.
URL Encoder / Decoder
Encode or decode URLs with percent-encoding. Handles query strings, special characters, and Unicode.
HTML Entities Encoder / Decoder
Encode special characters to HTML entities or decode HTML entities back to text. Essential for web developers.
Regex Tester & Validator
Test and validate regular expressions with real-time matching. Supports flags, groups, and common patterns.
Text Diff Checker
Compare two texts side by side and see the differences highlighted. Perfect for code review and document comparison.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds.
JWT Decoder
Decode JWT headers and payloads instantly. Inspect JSON Web Tokens in your browser without verifying or uploading the token.
UUID Generator
Generate random UUID v4 values in bulk. Copy lowercase, uppercase, hyphenated, or compact UUIDs.
Cron Expression Parser
Parse cron expressions into human-readable schedules. See next execution times, common examples, and field descriptions.
Number Base Converter
Convert numbers between binary, octal, decimal, hexadecimal, and custom bases. Real-time conversion with copy and validation.
JSON to CSV Converter
Convert JSON arrays and objects to CSV format. Flatten nested structures, choose delimiters, and export tabular data.
Image to Base64
Convert images to Base64 encoded strings. Generate data URIs, CSS background-image, and HTML img src code.
IP Address Lookup
Look up any IP address for geolocation, ISP, timezone, and more. Auto-detect your own IP instantly.
CSV Viewer & Formatter
View, sort, filter, and format CSV data in an interactive table. Auto-detect delimiters and convert to JSON.
Common tasks
FAQ
Do these developer tools upload my data?
Most tools run directly in your browser, which keeps pasted snippets local to your device.
Are these tools free to use?
Yes. FreeToolJet tools are free and do not require signup.