# Prysm Kiln Testnet: Fee Recipient

This document is a temporary location to talk about how to use the fee recipient feature in the Prysm Kiln Testnet.

Fee Recipient is the feature that allows users receive gas fees when proposing blocks for their specific validators post merge.

## Fee Recipient Config based on Teku Implementation
JSON file for defining validator public key to eth address
This will allow you to map your validators to corresponding eth addresses or generally cover the remaining keys with a default.

{
  "proposer_config": {
    "0xa057816155ad77931185101128655c0191bd0214c201ca48ed887f6c4c6adf334070efcd75140eada5ac83a92506dd7a": {
      "fee_recipient": "0x50155530FCE8a85ec7055A5F8b2bE214B3DaeFd3",
    }
  },
  "default_config": {
    "fee_recipient": "0x6e35733c5af9B61374A128e6F85f553aF09ff89A"
  }
}

`proposer_config` is optional
`default_config` is mandatory
`fee_recipient` is mandatory in each config

## New Flags

### Validator Client
- `suggested-fee-recipient` to set default eth address for ALL validators.
( i.e. --suggested-fee-recipient=0x046Fb65722E6b0000012BFEBf6177F1D2e9758D9)
- `fee-recipient-config-file` to set file location for fee recipient json.
( i.e. --fee-recipient-config-file=./fee_recipient_config.json)
- `fee-recipient-config-url` to set URL for fee recipient json.
( i.e. --fee-recipient-config-url=http://example.com/api/getFeeRecipient)

suggested fee recipient flag will override the configuration file.

you can not use both the file and url flags at the same time.

the validator client will send the fee recipient information at startup for all public keys that are active
as well as when the public key becomes active. It does this by calling the beacon api `prepareBeaconProposer`

### Beacon Node
- `suggested-fee-recipient` to set default eth address from validator client cli
( i.e. --suggested-fee-recipient=0x046Fb65722E6b0000012BFEBf6177F1D2e9758D9)

this sets the fall back default fee recipient on the beacon node if the validator restarts without fee recipient flags set

The beacon node will cache fee recipient information locally to be persistent.

### No Flags
by default Prysm uses the eth burn address (0x0000...)