Cosmos is a cross-chain protocol that is working to establish a standardized way for blockchains to inter-operate. It has been called the internet of blocchains. Cosmos is building a standardized protocol for multiple blockchains to operate freely together, and allow transfers of value between them. Cosmos is made up of a network of blocckhains called zones. Each of these zones will be powered by a the Tendermint consensus protocol. Cosmos will act as a hub, that ties the zones together and manages their coordination. The Cosomos token called ATOM was released in an ICO that raised $53 million, but it will not be traded until the platform is launched.

RChain is building a cross-chain blockchain platform that hopes to improve transaction speeds and scalability. RChain smart contracts are written in Rholang and are run concurrently on the Rho Virtual Machine. Rholang stands for reflective higher-order language, and supports internal concurrent programming to improve smart contract processing.
Rchain supports multiple blockchains on the same node, allowing them to interact and enabling secure cross-chain exchanges of value. It uses a Proof of Stake consensus algorithm and a form of compression called LADL (Logic as a Distributive Law) that is meant to improve DApp performance.
Unlike most blockchains that use public keys to distinguish virtual address spaces, RChain divides its virtual address space into namespaces A namespace is a set of named channels that are used to communicate the location of a network resource. Namespaces allow smart contracts on one blockchain to be visible to system contracts elsewhere on the network. Namespace developers can also use tools and properties to improve system encryption and protocols.
The platform is powered by the RHOC token.

AION calls itself a 3rd generation blockchain network, and is primarily focused on connecting blockchain networks. AOIN aims to solve the interoperability issues facing the various blockchains, and be the connecting bridge between them. AION's cross-chain platform has different consensus mechanisms for interchain and on-chain transactions. The on-chain consensus mechanism combines BFT (Byzantine Fault Tolerance), dPoS (Delegated Proof-of-Stake) and a new neural network inspired verification algorithm known as Proof-of-Intelligence.
Interchain transactions are managed by bridges. The bridges has a consensus mechanism that is different from the main AION chain, and each bridge is secured by an individual consensus. The bridge validators will be rewarded by interchain transaction fees.