Reference

The Fee Refunder module manages fee distribution for IBC packet acknowledgements and timeouts, ensuring relayers are compensated for successful packet delivery.

Parameters

Fee Structure

• recv_fee: Must be zero in Neutron (no receive fees)
• ack_fee: Fees paid for acknowledgement delivery
• timeout_fee: Fees paid for timeout delivery

Messages

MsgUpdateParams

Update module parameters through governance.

Authority Required: Governance only

Fields:

• authority: Governance authority address
• params: New module parameters

Queries

QueryParams

Retrieve the current module parameters.

CLI: neutrond query feerefunder params REST: GET /neutron-org/neutron/feerefunder/params

Response:

• params: Current Fee Refunder parameters including min_fee

QueryFeeInfo

Retrieve fee information for a specific IBC packet.

CLI: neutrond query feerefunder fee-info [port_id] [channel_id] [sequence] REST: GET /neutron-org/neutron/feerefunder/info

Parameters:

• port_id: IBC port identifier
• channel_id: IBC channel identifier
• sequence: Packet sequence number

Response:

• fee_info: Fee information containing payer, packet_id, and fee details

Events

The module emits the following events:

• lock_fees: When fees are locked for a new IBC packet
• distribute_ack_fee: When acknowledgement fees are distributed to relayers
• distribute_timeout_fee: When timeout fees are distributed to relayers

Key Concepts

• Automatic Distribution: Fees are automatically distributed when packets are acknowledged or timeout
• Relayer Compensation: Ensures relayers are paid for successful packet delivery
• Fee Escrow: Fees are locked when packets are sent and released upon completion
• Query-Only for Users: Users can only query fee information and parameters
• IBC Integration: Automatically handles fee distribution for IBC packets