Syscoin (SYS) is an open-source blockchain platform that strives to combine the robust elements of Bitcoin and Ethereum into a single, unified system. Launched in 2014, Syscoin is designed to provide a low-cost, scalable, and censorship-resistant data availability service known as PoDA. The platform's unique feature is its ability to allow miners to simultaneously mine both Bitcoin and Syscoin at no extra cost, effectively eliminating the risks of 51% attacks associated with Proof-of-Work (PoW) systems. Syscoin's architecture is dual-chain, consisting of an Ethereum-based blockchain called Network Enhanced Virtual Machine (NEVM) and a Bitcoin-based blockchain called Syscoin UTXO. This architecture aims to enable users and developers to leverage the strengths of both Bitcoin and Ethereum, creating new synergies between them.

Syscoin operates on a dual-chain architecture, with one chain based on Bitcoin's SHA-256 PoW model and the other on Ethereum's smart contract capabilities. This unique structure aims to offer the security of Bitcoin's consensus model and the flexibility of Ethereum's smart contracts. Syscoin's layer 1 consensus allows merged mining with Bitcoin, meaning miners can mine both Bitcoin and Syscoin simultaneously at no extra cost. Syscoin also provides decentralized finality on top of Nakamoto consensus, effectively eliminating the risks of 51% attacks. The platform utilizes incentivized full nodes, known as masternodes, to serve multi-quorum chainlocks for finality. Syscoin's native coin, SYS, is utility-focused and based on EIP-1559, and can be transferred between chains via the Syscoin Bridge and the Rollux Portal.

Syscoin aims to provide a platform that is suitable for a wide range of applications. Its dual-chain architecture makes it suitable for both simple value transfers and complex, Turing-complete computations. Syscoin's compatibility with Ethereum's smart contracts and rollups aims to make it a potential platform for decentralized applications (dApps), including those in the DeFi space. The platform's scalability and user experience aim to make it a potential solution for applications that require high transaction throughput, such as gaming and metaverse applications. Syscoin's opt-in compliance features also aim to make it a potential platform for projects that require regulatory compliance for their asset's transactions.

Syscoin was created in 2014 by Sebastian Schepis, a co-founder of the company that developed the Oracle Project Manager. Following the success of Project Manager, Sebastian consulted for large corporations. Today, Syscoin is led by the non-profit Syscoin Foundation, with board members including Jagdeep Sidhu, the Foundation President and Lead developer, and Michiel Näring, the Syscoin Foundation Vice President. The development of Syscoin's flagship apps and systems is led by SYS Labs. Syscoin's first layer 2, a fork of Optimism called Rollux, went live on June 28, 2023.