gaia and gaiad
gaia is the name of the Cosmos SDK application that implements the Cosmos Hub. gaiad is the single binary that runs it: the node daemon (gaiad start), the command line interface (CLI) for queries and transactions (gaiad query, gaiad tx), and the operator tools (gaiad init, gaiad config, gaiad keys, gaiad snapshots, gaiad comet). Source and releases are in the cosmos/gaia repository.
The current mainnet chain is cosmoshub-4, launched on 2021-02-18 at height 5200791 from the exported state of cosmoshub-3 (the genesis_time field keeps the cosmoshub-3 date of 2019-12-11). Earlier chain ids and their genesis files are kept in the cosmos/mainnet repository. The Archives page describes them.
What the Hub does
- Secures ATOM staking and delegation with a set of 180 active validators and a 21 day unbonding period.
- Runs on-chain governance for parameter changes, software upgrades, community pool spending, and signaling.
- Routes Inter-Blockchain Communication (IBC) transfers and packets between chains, with packet forward middleware and rate limiting on transfers.
- Hosts CosmWasm contracts through wasmd. Code upload permission is currently
Everybody(checked 2026-10-15 withcurl -s <rest>/cosmwasm/wasm/v1/codes/params). - Prices transactions with the feemarket module, which sets a dynamic minimum gas price with a floor of 0.005uatom.
- Offers liquid staking through the x/liquid module, with caps on how much stake may be liquid.
The stack the Hub runs today
The Hub currently runs gaia v28.3.1. That release is built on Cosmos SDK v0.53.4, CometBFT v0.38.23, ibc-go v10.7.0, wasmd v0.60.9, and Go 1.25.7. Every page in this section was checked against that release. The Versions page keeps the exact table. It also tells you which Cosmos SDK and CometBFT documentation version matches.Features that were removed
Older guides, forum posts, and search results still describe features that no longer exist in gaia. If you meet one of these, it is history, not a step you skipped.Interchain Security provider module: removed in gaia v28.0.0. The Hub no longer runs consumer chains. The
gaiad query provider and gaiad tx provider commands are gone. Pages about joining a consumer chain as a Hub validator no longer apply.Liquid staking module validator bond: replaced by the x/liquid module in gaia v25.0.0. Validators no longer post a validator bond; see Liquid staking.globalfee module: replaced by feemarket. The minimum gas price is dynamic, with a floor of 0.005uatom; see Feemarket.crisis module: removed. The flag in gaiad start --x-crisis-skip-assert-invariants does not exist on gaia v28. The node refuses to start with it. Start the node with gaiad start.What a node looks like on disk
Runninggaiad init creates a home directory, ~/.gaia by default, with two folders. Everything an operator configures or backs up is in one of them.
Default ports: 26656 (p2p), 26657 (RPC), 1317 (REST, disabled by default), 9090 (gRPC), 26660 (Prometheus, disabled by default). The Join mainnet page sets each file with
gaiad config set instead of hand editing.
The three validator keys
A validator has three keys. On the Hub today none of them can be rotated. The operator key (thecosmosvaloper address, kept in the keyring) signs validator transactions and can never be changed or replaced. Retiring it means creating a new validator and asking delegators to move. The consensus key (priv_validator_key.json) signs blocks. gaia v28.3.1 has no command to rotate it, so protect it and back it up. The node key (node_key.json) is the peer to peer identity. It carries no on-chain state and can be regenerated freely. The Validator setup and Security pages cover how to handle each one.
Where to go next
- Read Versions to confirm the stack and the testnet version.
- Check System requirements before buying or renting hardware.
- Then install gaiad.