What was launched

On March 13th 2019, the Cosmos Hub was launched. The goal of the Cosmos Hub is to be one of the main Hubs in the Cosmos Network. A Hub is a blockchain specifically designed to connect other blockchains together. The connection is made via a protocol called Inter-Blockchain Communication Protocol (IBC), which is not yet live but top priority as the next milestone in the Cosmos roadmap. Read the Cosmos Intro for more information on the Cosmos Network topology.

The Cosmos Hub launched with a functional Proof-of-Stake layer built on top of a BFT consensus engine called Tendermint Core. In addition to that, the Hub launched with its own implementation of a novel Proof-of-Stake design called Bonded Proof-of-Stake (BPoS).

A few days before the launch of the Cosmos Hub, a similar Hub called the IRIS Hub launched with the same properties. Both Cosmos Hub and Iris Hub are built on the Cosmos SDK, and will likely be important players in routing traffic across the Interchain. Even though these platforms are still MVPs, they set a strong precedent for the whole blockchain ecosystem, demonstrating that a new generation of tooling is now production-ready for developers to experiment with.

What Cosmos brings to the table

1. A production-grade BFT engine that can operate on the public Internet

The first thing that the successful launch of the Cosmos Hub marks is the advent of a new production-grade BFT engine: Tendermint Core.

The Cosmos Hub is built on top of Tendermint Core, which is the first implementation of a BFT consensus engine that can scale to hundreds of validators distributed on the public Internet (i.e. without direct connectivity between validator nodes).

Additionally, Tendermint is the only implementation of a BFT consensus algorithm in the blockchain space that offers strong safety guarantees. What this means is that Tendermint will never allow two honest nodes to see different versions of the state if the network is poorly connected. Transactions are final as soon as they are included in a block.

Currently, there is no Proof-of-Stake blockchain engine that can compare with Tendermint in terms of maturity and security. It has been under development since 2014, audited, formally proven, and is widely revered in the industry as the gold standard for Proof-of-Stake. Today, Tendermint Core is the highest grade choice for building public BFT Proof-of-Stake and private blockchain systems that are production-ready, and more than 89 projects are using it already.

2. A stable, upgradable SDK for building public or private chains from scratch

The Cosmos Hub, IRIS Hub, and many (but not all) of the blockchains currently being built within the Cosmos Network use the Cosmos SDK.

The Cosmos SDK is a general-purpose modular framework written in Golang for building application-specific blockchains on top of Tendermint BFT. It can be used to build both public and private blockchains.

The modularity of the SDK is its core strength. The SDK allows developers to compose their state machine from ready-to-use modules and abstracts away the complexity of having to integrate the higher level state machine logic with a consensus engine at the bottom of the stack. To build a blockchain on the Cosmos SDK, developers start by importing a few dependencies and ready-made modules that they might need like auth , bank , staking or gov . Then, they build their own custom module to implement the functionality they need for their specific use case. Finally, they link all these modules in the main application file, and compile the whole thing! At the end of this process, they have a fully-functional blockchain full-node client, light-client, as well as command land and REST interfaces to interact with their clients. You can try it now yourself by going through the SDK tutorial (https://cosmos.network/docs/tutorial/).

The Cosmos SDK is the only blockchain framework available today that lets you build public BFT blockchains from scratch that is mature enough for production-grade use cases. That is why it is being used by many of the most interesting projects in the space like Binance Chain, Lino, Terra, Trustory, Playlist, Sentinel, and many more.

For more on the Cosmos SDK, check out the SDK page.

3. A fully-functional Proof-of-Stake layer

The Cosmos Hub launched with a novel Proof-of-Stake design called Bonded Proof-of-Stake (BPoS). BPoS is a Proof-of-Stake protocol that works on top of a BFT consensus engine and incorporates all the necessary features for a complete Proof-of-Stake design baked right in the protocol.

BPoS is a Proof-of-Stake design based on bonding (locking) staking tokens (ATOMs) to prevent short range nothing-at-stake attacks that were a risk in earlier versions of Proof-of-Stake blockchains like Peercoin or NXT. It also includes delegation, so that any holder of the staking token (ATOM in the case of the Cosmos Hub) can participate and earn rewards in a secure way.

Additionally, BPoS implements full incentive mechanisms like fees and rewards distribution in-protocol and is the first Proof-of-Stake layer to work on top of a BFT engine. This sets BPoS apart from other mature implementations of Proof-of-Stake designs like that of Tezos. With BPoS, delegators do not have to trust their validators in any way to receive their rewards. However, they do need to perform careful due diligence on the validator(s) they delegate to, as slashing of validators for misbehaving also affects delegators.

The last good news is that BPoS is implemented as a set of open-source Cosmos SDK modules, namely staking , slashing , mint and distribution (fee distribution). You can freely reuse these modules to build your own Proof-of-Stake blockchain today.

What’s next

First, let’s recount all the new production-ready tools battle-tested by the launch of the Cosmos Hub:

Tendermint Core , a BFT consensus engine that can operate at scale on the public Internet.

, a BFT consensus engine that can operate at scale on the public Internet. The Cosmos SDK , a modular framework that lets you build production-ready blockchains on top of Tendermint Core.

, a modular framework that lets you build production-ready blockchains on top of Tendermint Core. A full suite of SDK modules to deploy a Proof-of-Stake incentive layer for your public blockchain with full incentives implemented in-protocol.

With these tools, you can build a custom public Proof-of-Stake blockchain application from scratch that can accommodate hundreds of transactions per second. This is a first step we’ve taken along a long roadmap.

The next milestone for the Cosmos ecosystem is the specification and deployment of the Inter-Blockchain Communication Protocol (IBC). The goal is to make the specification as general-purpose as possible, so that it can become the de facto Interchain communication protocol used across every chain. If you are interested in contributing, you can track the progress of IBC development here.

The good news is that you do not need to wait for IBC to start building on Cosmos. You can build your own blockchain on the Cosmos SDK today. When the IBC module becomes available, you will be able to plug the module into your code and your users can start interacting with extraneous chains immediately.