Sahyogi (સહાયોગી, "helper" in Gujarati) is a blockchain-anchored document management system built during HackGujarat 2020. It won the Portis × Matic (now Polygon) track for its practical real-world application: tamper-proof document storage for education, healthcare, defence, and productivity use cases.

The original project used live blockchain infrastructure (Portis wallet, Matic Mumbai testnet, Sia Skynet for decentralized file storage). With those services now deprecated, the project has been preserved as a fully static case-study mockup retaining the original architecture, visual design, and interaction patterns while simulating the blockchain layer via localStorage and the Web Crypto API.