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Stake Pool Operations

Stake pool operators use registerPool to register a new pool on-chain and retirePool to announce retirement. Both operations require the pool operator's key to sign the transaction.

Pool Registration​

Register a stake pool with full parameters — operator key, VRF key, pledge, cost, margin, relays, and optional metadata:

import {
  KeyHash,
  PoolKeyHash,
  PoolParams,
  RewardAccount,
  UnitInterval,
  VrfKeyHash,
  preprod,
  Client,
} from "@evolution-sdk/evolution"

const client = Client.make(preprod)
  .withBlockfrost({
    baseUrl: "https://cardano-preprod.blockfrost.io/api/v0",
    projectId: process.env.BLOCKFROST_API_KEY!
  })
  .withSeed({ mnemonic: process.env.WALLET_MNEMONIC!, accountIndex: 0 })

declare const operatorKeyHash: PoolKeyHash.PoolKeyHash
declare const vrfKeyHash: VrfKeyHash.VrfKeyHash
declare const ownerKeyHash: KeyHash.KeyHash
declare const rewardAccount: RewardAccount.RewardAccount

const poolParams = new PoolParams.PoolParams({
  operator: operatorKeyHash,
  vrfKeyhash: vrfKeyHash,
  pledge: 500_000_000n , // 500 ADA pledge
  cost: 340_000_000n ,   // 340 ADA fixed cost per epoch
  margin: new UnitInterval.UnitInterval({ numerator: 1n, denominator: 100n }), // 1% margin
  rewardAccount,
  poolOwners: [ownerKeyHash],
  relays: [],
  poolMetadata: null
})

const tx = await client
  .newTx()
  .registerPool({ poolParams })
  .build()

const signed = await tx.sign()
await signed.submit()

Pool Parameters Reference​

ParameterTypeDescription
operatorPoolKeyHashPool operator's key hash (28 bytes)
vrfKeyhashVrfKeyHashVRF verification key hash (32 bytes)
pledgeCoinOperator's pledge in lovelace
costCoinFixed cost per epoch in lovelace (min 340 ADA on mainnet)
marginUnitIntervalPool margin as a fraction (numerator/denominator)
rewardAccountRewardAccountWhere pool fees are collected
poolOwnersKeyHash[]Key hashes of all pool owners
relaysRelay[]Network relay endpoints (see below)
poolMetadataPoolMetadata?Optional metadata URL + hash

Relay Configuration​

Relays tell the network how to reach your pool. Use SingleHostAddr for IP-based relays:

import { IPv4, SingleHostAddr } from "@evolution-sdk/evolution"

const relay = new SingleHostAddr.SingleHostAddr({
  port: 3001n,
  ipv4: new IPv4.IPv4({ inner: new Uint8Array([192, 168, 1, 100]) }),
  ipv6: undefined,
})

Pass relays in the relays array of PoolParams.

Pool Metadata​

Link to off-chain metadata (pool name, description, ticker) hosted at a URL:

import { Bytes32, PoolMetadata, Url } from "@evolution-sdk/evolution"

declare const metadataHash: Bytes32.Bytes32

const metadata = new PoolMetadata.PoolMetadata({
  url: new Url.Url({ url: "https://my-pool.com/metadata.json" }),
  hash: metadataHash,
})

The metadata JSON file must follow the CIP-6 standard with fields like name, description, ticker, and homepage.

Pool Retirement​

Announce retirement effective at a future epoch:

import { PoolKeyHash, preprod, Client } from "@evolution-sdk/evolution"
import type { EpochNo } from "@evolution-sdk/evolution"

const client = Client.make(preprod)
  .withBlockfrost({
    baseUrl: "https://cardano-preprod.blockfrost.io/api/v0",
    projectId: process.env.BLOCKFROST_API_KEY!
  })
  .withSeed({ mnemonic: process.env.WALLET_MNEMONIC!, accountIndex: 0 })

declare const poolKeyHash: PoolKeyHash.PoolKeyHash
declare const retirementEpoch: EpochNo.EpochNo

const tx = await client
  .newTx()
  .retirePool({
    poolKeyHash,
    epoch: retirementEpoch,
  })
  .build()

const signed = await tx.sign()
await signed.submit()

Retirement takes effect at the specified epoch. The pool deposit (500 ADA on mainnet) is refunded to the pool's reward account after retirement.

Update Pool Parameters​

To update an existing pool's parameters (cost, margin, relays, metadata), submit a new registerPool with the updated PoolParams. The chain treats this as an update if the operator key hash matches an existing pool.

Next Steps​