@txfence/cosmos

Cosmos SDK / IBC chain adapter. Supports Cosmos Hub (cosmoshub-4) and Osmosis (osmosis-1). Works with any Cosmos SDK chain via standard gRPC/REST endpoints.

simulateCosmosAction

Simulates a Cosmos SDK message via the transaction simulation endpoint.

async function simulateCosmosAction(
  action: Action,
  chainId: 'cosmoshub' | 'osmosis',
  rpcUrl: string
): Promise<SimulationResult>

Returns gas estimate and whether the message would succeed. Cosmos simulation is generally more reliable than EVM simulation since account state is locked during simulation.

executeCosmosAction

Signs and broadcasts a Cosmos SDK transaction.

async function executeCosmosAction(
  action: Action,
  chainId: 'cosmoshub' | 'osmosis',
  rpcUrl: string,
  signer: OfflineSigner,
  evaluation: PolicyEvaluation,
  simulation?: SimulationResult
): Promise<SuccessReceipt>

buildCosmosTransaction

Constructs a TxBody from a txfence Action.

async function buildCosmosTransaction(
  action: Action,
  chainId: string,
  senderAddress: string
): Promise<TxBody>

Supports:

• MsgSend for native token and IBC denom transfers
• MsgExecuteContract for CosmWasm contract calls (Osmosis)
• IBC MsgTransfer for cross-chain transfers

createCosmosSignerFromMnemonic

Creates an OfflineSigner from a BIP39 mnemonic. Not for production — use a Ledger or KMS in production.

function createCosmosSignerFromMnemonic(
  mnemonic: string,
  prefix?: string   // bech32 prefix, default 'cosmos'
): Promise<OfflineSigner>

Chain IDs

Native token amounts

Cosmos uses uatom (micro ATOM) and uosmo (micro OSMO). The adapter normalizes amounts using the decimals field:

const action: TransferAction = {
  kind: 'transfer',
  chain: 'cosmoshub',
  token: {
    token: 'ATOM',
    amount: 1_000_000n,   // 1 ATOM = 1,000,000 uatom (6 decimals)
    decimals: 6,
  },
  to: 'cosmos1...',
}