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Developer Tools

Browse 20 free browser tools for developer tasks, available directly in your browser.

20 tools

About these tools

These are the small utilities that interrupt real work: a query that arrived as one unreadable line, a config file that will not parse, a token whose expiry you need to read, a shadow that needs four numbers adjusted together. Each one does a single job and hands you something you can paste.

The formatters and validators are parser-based rather than regular expressions, which matters for the cases that actually bite — a keyword inside a string literal is text, not a keyword, and a tool that does not know the difference will corrupt your data while appearing to work.

Nothing you paste is transmitted. That is worth knowing for the JWT inspector in particular: tokens routinely contain user identifiers and claims, and pasting a production token into a remote service is a habit worth not having. Even so, prefer a test token — the safest secret is one that was never in a browser at all.

Format and validate

Make a file readable, or find out why it will not parse.

CSS generators

Build a value visually and copy the rule.

Identifiers, text and encoding

Inspect a token, check a UUID, convert between markup formats.

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