A growing toolkit of free developer utilities with optional AI enhancement. No ads, no account, no BS.
The most-used tools from the HeoLab collection, with AI explanations built in.
Convert Unix timestamps to human-readable dates and vice versa. Supports all major timezone formats.
Test regular expressions against strings in real-time. Visualize matches, groups, and flags.
Decode and inspect JSON Web Tokens. View header, payload, and verify structure instantly.
No tutorials, no setup. Every tool works the moment you open it.
Browse by category or search for the exact utility you need. Every tool has a dedicated page with examples.
Drop in JSON, JWTs, regex patterns, timestamps — whatever you have. No account, no upload limits.
Results appear in milliseconds. Use optional AI enhancement to get plain-English explanations of complex outputs.
Not another ad-stuffed, slow, privacy-invading toolbox. HeoLab is different by design.
Your data never leaves your browser for client-side tools, and our servers log nothing. No cookies, no tracking.
No waiting for server round-trips. Most tools run entirely in your browser for sub-millisecond execution.
Opt-in AI explanations powered by Claude. Understand your data, not just process it. Always optional.
Deep dives, tutorials, and security guides.
A practical guide to lookahead and lookbehind assertions — the most powerful regex features with real examples.
Regex can be slow — learn how to avoid catastrophic backtracking, optimize your patterns, and use the right tools for the job.
How to use regular expressions for form validation in JavaScript and HTML — with reusable patterns and common mistakes to avoid.