Developer Parsers & Encoders
Format, encode, parse, and inspect developer data entirely client-side. Protect sensitive code and tokens with these secure, zero-upload dev tools.
Why use offline developer utilities?
Every time you paste a JWT token, a private key, or a customer record into an online tool, you are trusting a server you cannot audit. Browser-based developer utilities eliminate that risk entirely because they run as client-side JavaScript, which means your data never leaves the tab.
The tools in this category cover the most common data-wrangling tasks: validating JSON before feeding it to an API, encoding a binary blob as Base64 for transport, generating collision-resistant UUIDs without relying on a remote service, and inspecting cron expressions in plain English. All of it happens locally, with no logging, no analytics on your inputs, and no rate limits.
Because the tools are statically served, they also work offline after the initial page load. Bookmark them once and you have a reliable local toolbox that is available even when your internet connection is not.
No. Tokens, JSON, and code all stay in your browser tab. Nothing is transmitted.
Yes. Once the page loads, you can disconnect and keep working. Useful when handling sensitive data and you want to be certain nothing leaves your machine.
No. CapyToolkit doesn't require an account, login, or API key. Open a tool and use it.
No. Rate limits only exist when a server is involved. These tools have no server.
Yes, by design. CapyToolkit doesn't log or store any input. You can verify it yourself by opening your browser's network tab while using any tool. You won't see outgoing requests.
Chrome, Firefox, Edge, and Safari on current stable versions. Most tools also work on mobile browsers.
Request a tool or share feedback
Have an idea for a new tool? Leave a message about what you'd like to see added.