In one sentence
Ethereum’s idea is “one big chain where every app lives”. Cosmos’s idea is “every app can have its own chain, and a network connects those chains”. It provides three things:
- CometBFT (formerly Tendermint): a ready-made consensus engine that handles block production and voting.
- The Cosmos SDK: a chain-building framework with ready modules for staking, governance, transfers and more, so projects only write their own business logic.
- IBC: a chain-to-chain communication protocol that lets two Cosmos chains send tokens and messages to each other directly, with no third-party custodian.
dYdX and Injective, mentioned in the Custom chains guide, were both built with this kit.
How each Cosmos chain produces blocks
Chains using CometBFT usually have from a few dozen to one or two hundred validators who take turns proposing blocks according to stake. A block is committed only once it has signatures from more than two-thirds of the stake, and once committed it is final; there is no “wait a few blocks to be safe”.
The cost: if more than a third of validators go offline or misbehave, the chain simply stops (it would rather halt than produce a bad block). Halts are not unusual in the Cosmos ecosystem’s history, usually because an upgrade went wrong or validators failed to keep up.
Data as of 16 Oct 2026, 01:45 UK time · source Cosmos Hub public node, CoinGecko, DefiLlama
IBC: how chains send tokens to each other
- 01Locked on chain A
You start a transfer on chain A and the tokens are locked in chain A's IBC module.
One block - 02Relayed
A relayer carries the "packet" and chain A's proof to chain B. Relayers only carry data; they cannot forge it.
- 03Verified on chain B
Chain B runs a light client of chain A and verifies for itself that the lock really happened.
- 04Voucher minted on chain B
Chain B mints a voucher representing the tokens, named something like ibc/27394FB…, recording which chain and channel it came from.
- 05Burned and unlocked on return
When the voucher goes back to chain A it is burned on chain B, and chain A unlocks the originals.
Unlike most bridges, IBC does not rely on a set of signers to release funds; the two chains verify each other's block headers. Security depends on each chain's own validators.
The awkward position of ATOM and the Cosmos Hub
ATOM is the token of one chain, the Cosmos Hub, used for staking and voting on the Hub. But other Cosmos chains do not need ATOM: they have their own tokens and their own validators. The kit is free and open source, so more projects building with it does not necessarily make ATOM more valuable.
The community has tried several fixes, such as the 2022 “ATOM 2.0” proposal (voted down) and “replicated security” launched in 2023 (letting small chains rent the Cosmos Hub’s validators), but how ATOM captures value has remained a point of contention.
Another name you cannot avoid is Terra: it too was built with the Cosmos SDK, and in May 2022 its algorithmic stablecoin UST lost its peg; LUNA and UST went to zero within days, wiping out tens of billions of dollars. This had nothing to do with Cosmos technology; the problem was UST’s design. But it shows one thing: chains built with the same kit can differ enormously in quality.
Locked value on several Cosmos chains
- dYdX$70.3M
- Sei$30.6M
- Kava$20.7M
- Injective$14.4M
- Osmosis$10.8M
- Cosmos Hub$137K
- Archway$116K
Data as of 16 Oct 2026, 01:45 UK time · source DefiLlama
Compared with Ethereum and Solana these numbers are small: the Cosmos ecosystem’s value lies more in “many projects use it to build chains” than in how much is locked on any one chain.
Strengths and trade-offs
- Building a chain is easy with ready-made modules, suiting apps that need a chain of their own.
- Blocks are final as soon as they are committed; there is no rollback.
- IBC relies on chains verifying each other, which is more trustworthy than bridges that rely on signers.
- Every chain has to find its own validators; small chains have few validators and concentrated stake, so security is limited.
- If more than a third of validators fail the chain halts, and halts have not been rare.
- ATOM's value is not directly tied to the health of the whole ecosystem, and total locked value across it is modest.
- 01
Which chain does the token actually live on? On other chains the same token becomes an ibc/… voucher; check which channel it came from.
- 02
How many validators does the chain have, and how much voting power do the top ten hold? If the top few together exceed a third, there is a risk of halts or censorship.
- 03
Has the chain halted before, for how long, and how did it recover?
- 04
On-chain governance: proposal thresholds, turnout, and whether key parameters (inflation, unlocks) have been changed recently.
- 05
For algorithmic stablecoins and high-yield deposit schemes, think first about how Terra collapsed.
Data and sources
- Live figures: Cosmos Hub public node (block time, validator count), CoinGecko (ATOM market cap) and DefiLlama (locked value per chain).
- Mechanisms are based on the official Cosmos documentation and the IBC protocol specification.
- This guide is educational and is not investment advice.
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