Qubit is a decentralized protocol that provides permissionless access to real quantum computing infrastructure. It allows users to execute circuits on live quantum processing units (QPUs), access native quantum randomness, and experiment with quantum-secure primitives directly on-chain. Designed to bridge the gap between cutting-edge quantum hardware and the evolving landscape of Web3, Qubit enables developers, researchers, and everyday users to engage with real quantum computing through a streamlined blockchain interface. Its mission is to democratize access to quantum resources and foster a new generation of decentralized applications that integrate quantum capabilities. The platform operates on-chain, with smart contracts governing access, verification, and usage of quantum compute jobs. Users can submit quantum circuits via the Qubit interface, route them to live QPUs, and retrieve the results, all while maintaining full transparency and verifiability on the blockchain. Beyond computational access, Qubit offers tools focused on quantum security, including quantum-secure key generation and post-quantum cryptographic primitives. These features are designed to help users and protocols future-proof their infrastructure against the anticipated risks of quantum attacks on classical encryption systems.