What Is Cosmos (ATOM)? The Chains That Talk to Each Other

On 22 June 2022 the team behind dYdX, a crypto derivatives exchange running on an Ethereum scaling layer called StarkEx, announced that its next version would leave for a blockchain of its own. Its complaint was blunt: no chain it could build on, layer 1 or layer 2, came anywhere near the throughput a proper order book and matching engine needs. So it built one.

The dYdX Chain produced its first block on 26 October 2023 and opened for trading on 14 November. Each validator holds the order book in memory and matches orders off-chain, and only the finished trades are written into each block, a job description dYdX could only write on a chain it controlled.

The kit it used is Cosmos, less a single blockchain than a way of making them: software for launching a chain dedicated to one application, plus a shared protocol those chains use to pass tokens and messages between them. The Cosmos Hub and its ATOM token sit inside that system as one chain among many. This page explains the machinery and is not financial advice.

Where the kit came from

The consensus engine came first, and in 2014 Jae Kwon published a paper titled Tendermint: Consensus without Mining, which replaced miners with a known set of validators who vote on each block. A block goes through once validators holding more than two-thirds of the voting power sign it, and the system stays correct as long as fewer than a third of them are faulty or malicious.

Kwon and Ethan Buchman followed with the Cosmos whitepaper in 2016. On 6 April 2017 the Interchain Foundation, a Swiss non-profit, opened its fundraiser and hit its $17 million cap in roughly half an hour.

The engine has since been renamed: in February 2023 Tendermint Core was forked as CometBFT, now maintained as its successor, and Osmosis and the dYdX Chain both run it today.

On top sits the Cosmos SDK, a framework written in Go that hands a new chain ready-made modules for accounts, staking, governance and token transfers, leaving the team to write only the part that makes its application different. Its maintainers count more than 200 chains built with it in production, as of September 2026, a few of them:

• Osmosis, a decentralised exchange for tokens arriving from other chains, went live on 18 June 2021.

• Celestia launched its mainnet beta on 31 October 2023, built to publish and store transaction data for other chains.

• Terra was home to UST, the stablecoin that collapsed in May 2022.

• Neutron, a smart-contract platform, launched in May 2023 on validators borrowed from the Cosmos Hub, a story picked up further down.

Every one of them has its own token.

How IBC connects the chains

Independent chains are only half the design, and the other half is IBC, the Inter-Blockchain Communication protocol, which reached the Cosmos Hub with the Stargate upgrade in February 2021; token transfers over it were switched on after a governance vote, on 29 March.

Neither side has to trust a middleman, because each chain keeps a light client of the other, a compact record of the other chain's validators and block headers, and uses it to check proofs for itself. Messages are carried by relayers, off-chain processes that anyone can run. A relayer can delay a packet but cannot forge or alter one, because the receiving chain verifies every packet against its light client before acting on it.

Tokens move by escrow: send ATOM to Osmosis and the originals are locked on the Hub while Osmosis mints a matching voucher, which is burned when the ATOM goes home. On Osmosis that voucher is recorded as ibc/ followed by a 64-character hash of the route it took, beginning 27394FB0, a label that records where it came from.

The same plumbing carries dollars: the only collateral asset on dYdX's chain is USDC that crossed over from Noble, a Cosmos chain where Circle issues USDC natively, and its on-chain label traces straight back along that route.

The traffic is measurable, too: in the 30 days to 28 September 2026, Map of Zones, which tracks IBC activity, counted about 4 million transfers worth roughly $2.2 billion across 90 active chains. The busiest route by value, about $374 million, ran between dYdX's chain and Noble.

The Hub, and what ATOM is for

The Cosmos Hub produced its first block at 23:00 UTC on 13 March 2019, the first chain to run the SDK in production, and it launched with ATOM transfers switched off.

ATOM does its work on the Hub itself. Holders stake it behind validators to secure the chain under proof of stake, and the 180 validators with the most stake form the active set. The same ATOM carries votes on governance proposals and pays transaction fees on the Hub.

Staking comes with penalties: a validator caught signing two different blocks at the same height loses 5% of the ATOM bonded to it, delegators' share included, and is barred from the validator set for good. One that misses more than 95% of a 10,000-block window loses 0.01% and is jailed for ten minutes. Unstaking takes 21 days, and stake on its way out can still be punished for faults committed before it left.

Which leaves an awkward question: Osmosis, Celestia and dYdX's chain have their own validators and tokens and need nothing from the Hub to keep producing blocks, so what does the Hub add?

The first big answer failed. ATOM 2.0, unveiled in 2022, proposed new jobs for the Hub, including a cross-chain block space marketplace and a fund for new chains, plus a rewrite of how new ATOM is issued. Put to a vote as Proposal 82, it was rejected on 14 November 2022: 47.51% voted yes, but 37.39% chose NoWithVeto, over the 33.4% veto threshold.

The second answer shipped. Interchain Security, switched on in 2023, let the Hub's validators produce blocks for consumer chains, and Neutron became the first that May. In April 2025 Neutron left to run as a sovereign chain with its own validator set.

Polkadot made the opposite bet

Polkadot tackles the same problem from the other end. Its relay chain's validators secure every connected parachain, so a new chain has strong security from its first day but accepts the relay chain's rules and pays for its place.

A Cosmos chain starts sovereign, recruiting its own validators and writing its own rules, which is how dYdX could rebuild the validator's job around an order book. The cost is that a small chain is only as hard to attack as the stake it can attract. Interchain Security was the Hub's version of the Polkadot deal, and its first customer chose independence inside two years.

What Terra showed

Terra was the harshest test of the model. Its UST stablecoin began slipping from its dollar peg on 9 May 2022, and within days the Terra chain had been halted, with tens of billions of dollars of market value gone inside a week.

The halt stopped Terra alone, since no other chain relied on Terra's validators to produce its blocks. What spread was the loss: any UST sitting on other chains as an IBC voucher was only ever a claim on UST locked on Terra, so it fell with the original wherever it was held.

The kit also made a quick restart possible. At 06:00 UTC on 28 May 2022, 19 days after the slide began, a brand-new chain started under the Terra name, and the original carried on as Terra Classic.

That is the practical lesson for anyone holding tokens across Cosmos. A voucher's name tells you the route it travelled, and the voucher is only ever as sound as the chain at the far end.