RSK is an open source smart contract platform that is secured by the Bitcoin network. RSK is designed to add value and increase the functionality of the Bitcoin ecosystem by providing smart contracts that are compatible with the network's code and can be written in Solidity. RSK smart contracts are powered by the SmartBitcoin (RBTC) which is linked to Bitcoin. (1 RBTC=1 BTC)
RSK developed the RIF Token which is intended to enable users to access a range of DApps within their ecosystem. In September 2019, RSK purchased the Spanish social media platform Taringa with the goal of using the RIF token as an incentive to encourage users to share content.

Nethereum is an open source .NET integration library for Ethereum. It is designed to help developers easily integrate the Ethereum blockchain into their .NET applications. It consists of modular libraries for features that are covered are writing smart contracts, cryptographic wallets, DApps, and managing blockchain data.

Chain is a blockchain software company that creates blockchain-based systems for financial institutions and major companies. They've developed blockchain solutions for companies like Nasdaq, Visa, and Citigroup, as well as a variety of crytpocurrencies. Chain has been successful in incorporating distributed ledger technology in very large and influential companies. Their focus is on using the core innovations of blockchain to improve existing systems. Chain uses blockchain as a software tool that can be applied where it is important for services or product to have more trust, or to build a network without an intermediary