Developer Tools Tools
Free Online Developer Tools
Essential utilities for developers that run entirely in your browser. Format JSON, encode Base64, generate UUIDs, test regular expressions, and encode URLs — all client-side with no data sent to any server.
Why developer tools should run in the browser
Server-based developer tools introduce unnecessary risk — your API keys, JWT tokens, database passwords, and sensitive payloads are transmitted to a third-party server every time you paste them into an online tool. Browser-based tools eliminate this risk entirely.
Every tool on this page uses only browser-native APIs: JSON.parse() for formatting, TextEncoder for Base64, crypto.randomUUID() for UUIDs, and the RegExp engine for regex testing. No npm packages, no network requests, no external dependencies.
Performance is also better — client-side tools respond instantly with no round-trip latency. Large JSON files, long Base64 strings, and complex regex patterns all process at native JavaScript speed.
Developer Tools best practices
FAQ
Common questions
Is it safe to paste API keys into these tools?
Yes — these tools run entirely in your browser. Your input is never transmitted anywhere. You can verify by opening DevTools → Network tab and confirming zero network requests while using the tools.
What is the difference between Base64 encode and URL encode?
Base64 converts binary data to ASCII text using 64 printable characters. URL encoding converts special characters to percent-encoded sequences safe for URLs. They serve different purposes and are not interchangeable.
When should I use UUID v4?
Use UUID v4 for database primary keys, session tokens, file names, and any identifier that must be unique without a central authority. UUID v4 is randomly generated with 122 bits of entropy — collision probability is negligible.
What JSON indentation should I use?
2 spaces is the JavaScript/Node.js convention. 4 spaces is common in Python and Java. Both are valid — consistency within a project matters more than the specific choice.
What regex flags does the tester support?
The tester uses JavaScript's ECMAScript RegExp engine and supports all standard flags: g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode), and y (sticky).
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