This site starts with a small question: how do I calculate if an integer is odd? The answer is short. The interesting details fill a library.
Useful first. Absurd second.
The calculator checks decimal integer text in your browser. It never sends your number to an AI service. It supports up to 1,000 digits and uses the last digit to classify parity, so it avoids JavaScript Number rounding. Our code guides explain which inputs each example accepts.
The Jev connection
Jake Casto built is-jodd, an intentionally overengineered companion to is-jeven. Aurélien Bobenrieth suggested the name. It asks TypeSafe AI’s Jev model whether an integer is odd. That package has a custom trillion-dollar license; it is a joke project, with real benchmarks. This free calculator does not call or import the package.
How to read our guides
Guides provide direct answers, worked examples, explicit edge cases, and links to primary documentation where relevant. The Jev articles reflect documentation consulted on September 22, 2026. Model aliases and API behavior can change; check the linked provider documentation before an integration.
Our benchmark article reports the full result, including a test that did not show a consistent speed advantage. A short experiment is not a universal performance guarantee.
Corrections and independence
This is an independent site by Jake Casto. Follow @0x15f on X / Twitter for projects and experiments. It is not affiliated with, endorsed by, or operated by TypeSafe AI. Found an issue? Open a correction on GitHub with the page and a reproducible example.