Free Online Developer Tools

Fast, private, and free tools for developers. JSON formatting, Base64 encoding, JWT debugging, regex testing, and more. All processing happens in your browser — no data is ever uploaded.

No sign-up required

100% client-side processing

Completely free

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JSON Formatter

Format, validate, and beautify JSON data. Tree view, error highlighting, and minify support.

Base64 Encode/Decode

Encode text to Base64 or decode Base64 strings back to text. Support for UTF-8 and binary.

URL Encoder

URL-encode or decode text strings. Handle query parameters and special characters safely.

Timestamp Converter

Convert Unix timestamps to human-readable dates and vice versa. Support for seconds and milliseconds.

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JWT Debugger

Decode and inspect JWT tokens. View header, payload, and verify signature structure.

Regex Tester

Test regular expressions with real-time matching. Highlight groups and see match details.

Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-512 hashes. Compute HMAC with secret keys.

UUID Generator

Generate random UUIDv4 and time-based UUIDv7 identifiers. Batch generation supported.

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QR Code Generator

Generate QR codes from text or URLs. Download as PNG or SVG. Customizable colors and size.

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Markdown Previewer

Write and preview Markdown in real-time. GitHub-flavored markdown with syntax highlighting.

This site is under active development

Got a tool request or feedback? 1326813680@qq.com

Why Choose Our Developer Tools?

Privacy First

Every tool runs entirely in your browser. Your data never leaves your device. No servers, no logs, no tracking.

Lightning Fast

No network round-trips for processing. Instant results as you type, with zero latency.

Always Free

All tools are free to use with no limits. No sign-up, no paywalls, no usage quotas.