About FizzKit

FizzKit is a collection of focused, free tools for developers and ad-tech engineers — JSON, JWTs, regex, VAST, OpenRTB, consent strings and more. Almost every tool runs 100% in your browser. A few live tools (the Request Bin, the RTB Bidder Sandbox and any “fetch by URL” feature) use a small FizzKit relay so you can receive real traffic or read a file from another domain; those tools say so on their page.

The project exists because most "online tools" sites are slow, covered in ads, and paste your data into a server you have no reason to trust. FizzKit is the opposite: fast, private, and focused on the task at hand.

Privacy policy

Tools marked “Runs locally in your browser” never send your input anywhere. Formatting, encoding, hashing and parsing happen on your device. When you close the tab, nothing about your session remains with us.

Tools marked “Uses the FizzKit relay” create a temporary endpoint or fetch a public URL on your behalf. Captured requests and fetched responses are held in memory only — never written to disk or logged — and are deleted automatically 60 minutes after the last activity (never later than 3 hours after creation) (or sooner if you press Clear or New endpoint). The relay refuses private and internal network targets.

Tools marked “loads a third-party SDK” (the VAST Ad Tester) load Google’s IMA SDK in your browser; the ad tag you enter is requested by that SDK directly, as it would be by any video player.

The site uses local storage in your browser for optional conveniences: your theme, pinned and recently used tools, and per-tool settings. Secrets (signing keys, HMAC secrets, bcrypt passwords) are never persisted. You can clear everything from your browser’s site settings.

FizzKit uses Google Analytics for aggregate page-view counts, does not use tracking cookies for advertising, and does not sell or share your data.

Feedback

Found a bug or want a new tool? The site is actively maintained. Check back regularly as the catalog grows.