Cosmos

Cosmos is a decentralised ecosystem of independent, interconnected blockchains, often called the 'Internet of Blockchains.' The Cosmos Hub — the first chain in the ecosystem and home of the ATOM token — was founded by Jae Kwon and Ethan Buchman and launched in March 2019 with a vision fundamentally different from monolithic blockchains: instead of forcing all applications onto a single chain, Cosmos enables developers to build their own sovereign, application-specific blockchains that can communicate with each other trustlessly. Each chain in the ecosystem owns its own state, consensus, tokenomics, and governance, and pays no rent to a shared 'main chain' the way rollups do.

At the heart of the Cosmos ecosystem is the Inter-Blockchain Communication (IBC) protocol, an open standard for transferring data and tokens between independent blockchains. IBC has become one of the most successful interoperability solutions in crypto, connecting more than 100 sovereign blockchains including Osmosis (the flagship DEX), Injective (financial appchain), Celestia (modular DA), dYdX (perpetuals), Stride (liquid staking), Neutron (smart contracts on Interchain Security), and dozens of others. Unlike third-party bridges that rely on trusted multisigs or oracles, IBC uses light-client verification for trustless cross-chain communication: each chain runs a lightweight copy of the other chain's consensus, so it can verify claims about the other chain's state directly.

The Cosmos SDK is the open-source framework used to build these application-specific blockchains (called 'appchains'). It provides modular components for consensus (via CometBFT, formerly Tendermint BFT), networking, staking, governance, and state machine logic, allowing developers to customise every aspect of their blockchain by composing modules and writing application-specific logic. This approach has attracted major projects: dYdX v4 migrated from Ethereum to its own Cosmos appchain to gain a fully decentralised orderbook, Celestia — the leading modular data availability layer — is built with the Cosmos SDK, and dozens of enterprise, gaming, and privacy chains use it as their base.

The Cosmos Hub itself has undergone several evolutions. Interchain Security (ICS) v1 allows the Hub to lease its validator set to smaller 'consumer chains' (Neutron and Stride are the flagship users), giving them mainnet-grade security without bootstrapping their own validator set. ATOM 2.0 proposals in 2022 attempted a broader restructuring of the Hub's economics and governance but were rejected by governance. Ongoing work focuses on ICS v2 (partial security), Mesh Security (bilateral security-sharing across sovereign chains), and reducing ATOM inflation. In 2024-2025 governance also approved ATOM's evolution toward a fixed maximum supply and lower inflation, marking a shift from earlier tokenomics.