Developer Tools: Free, Private, No Tracking
Eighteen tools for the small tasks that interrupt development work: decoding a token, formatting a payload, working out what a cron expression does. All of them run entirely in your browser, which matters here more than in most categories, since the input is often a real token or a production configuration.
Encoding & Data
Hashing & IDs
Networking & Numbers
Date & Time
Text & Code
Design & Color
Why local processing matters for these tools
The typical input to a developer tool is not neutral. Decoding a JWT means pasting a session token. Formatting a JSON response means pasting whatever that response contained, frequently including customer data. Diffing two configuration files means pasting connection strings and API keys.
Sending that to an unknown server is a habit worth avoiding, and many online tools do exactly that without saying so. Every tool here is implemented in JavaScript running in your browser. After the page loads, the operation itself makes no network request, which you can verify in the Network tab of your browser's developer tools.
One tool deliberately omits a feature for the same reason: the JWT decoder does not verify signatures, because verification would require you to paste your signing secret. A site asking for that is asking for the key to forge tokens for every user of your system. Verification belongs in your server-side middleware.
Which tool for which task
| Task | Tool |
|---|---|
| Decode a Base64 string or data URI | Base64 |
| Escape a value for a URL query string | URL encode |
| Read a minified API response | JSON formatter |
| Generate typed models from a payload | JSON to C# |
| Turn a spreadsheet export into JSON | CSV and JSON |
| Verify a download checksum | Hash generator |
| Create a unique identifier | GUID generator |
| See what claims a token carries | JWT decoder |
| Convert between hex, binary, and decimal | Number base |
| Work out a network's usable host range | Subnet calculator |
| Convert a log timestamp to a date | Unix timestamp |
| Decode a .NET DateTime.Ticks value | .NET ticks |
| Understand or write a cron schedule | Cron expressions |
| Rename identifiers between conventions | Case converter |
| Test a pattern you already have | RegEx tester |
| Build a pattern you do not know yet | RegEx builder |
| See what changed between two files | Text diff |
| Convert a colour between HEX, RGB, and HSL | Colour converter |
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