Integrating stacking delegation

In this guide, you'll learn how to integrate the Stacking delegation flow by interacting with the respective smart contract, as well as reading data from the Stacks blockchain.

This guide highlights the following capabilities:

As an account holder: delegate STX tokens
As a delegator: Stack STX token on behalf of the account holder
As a delegator: Commit to Stacking with all delegated STX tokens

Prerequisites#

First, you'll need to understand the Stacking delegation mechanism.

You'll also need NodeJS 12.10.0 or higher to complete this tutorial. You can verify your installation by opening up your terminal and run the following command:

node --version

Finally, you need to have access to at least two accounts (STX account holder and delegator). For testing purposes on the testnet, you can use the CLI to generate them:

stacks make_keychain -t > account.jsonstacks make_keychain -t > delegator.json

You can use the faucet to obtain testnet STX tokens for the test account. Replace <stxAddress> below with your address:

curl -XPOST "https://stacks-node-api.testnet.stacks.co/extended/v1/faucets/stx?address=<stxAddress>&stacking=true"

Step 1: Integrate libraries#

Install the stacking, network, transactions libraries, and bn.js for large number handling:

npm install --save @stacks/stacking @stacks/network @stacks/transactions bn.js

info

See additional Stacking library reference

Step 2: Delegate STX tokens#

To get started, delegate STX tokens as an account holder.

import { getNonce } from "@stacks/transactions";import { StacksTestnet, StacksMainnet } from "@stacks/network";import { StackingClient } from "@stacks/stacking";import BN from "bn.js";
// for mainnet: const network = new StacksMainnet();const network = new StacksTestnet();
// the stacker STX addressconst address = "ST3XKKN4RPV69NN1PHFDNX3TYKXT7XPC4N8KC1ARH";
const client = new StackingClient(address, network);
// how much to stack, in microSTXconst amountMicroStx = new BN(100000000000);
// STX address of the delegatorconst delegateTo = "ST2MCYPWTFMD2MGR5YY695EJG0G1R4J2BTJPRGM7H";
// burn height at which the delegation relationship should be revoked (optional)const untilBurnBlockHeight = 5000;
// hash of bitcoin address that the delegator has to use to receive the pool's rewards (optional)const poxAddress = undefined;
// private key of the account holder for transaction signingconst privateKey =  "d48f215481c16cbe6426f8e557df9b78895661971d71735126545abddcd5377001";
const delegetateResponse = await client.delegateStx({  amountMicroStx,  delegateTo,  untilBurnBlockHeight, // optional  poxAddress, // optional  privateKey,});
// {//   txid: '0xf6e9dbf6a26c1b73a14738606cb2232375d1b440246e6bbc14a45b3a66618481',// }

This method calls the delegate-stx method of the Stacking contract. Note, that the amount can be higher or lower than the current account balance. Delegation does not yet lock the STX tokens, users can still transfer them.

tip

To avoid handling private keys, it is recommended to use the Stacks Wallet to sign the delegation transaction

Congratulations! With the completion of this step, you successfully learnt how to use the Stacking library to delegate STX tokens as an account holder.

Optional: Revoke delegation rights#

Delegators will be able to Stack STX tokens on the account holder's behalf until either the set burn height is reached or the account holder revokes the rights.

To revoke delegation rights, the account holder can call the revokeDelegatestx method.

const revokeResponse = await client.revokeDelegateStx(privateKey);
// {//   txid: '0xf6e9dbf6a26c1b73a14738606cb2232375d1b440246e6bbc14a45b3a66618481',// }

This method calls the revoke-delegate-stx method of the Stacking contract.

tip

To avoid handling private keys, it is recommended to use the Stacks Wallet to sign the revoke transaction

Step 3: Stack delegated STX tokens#

With an established delegation relationship, the delegator can stack STX tokens on behalf of the account holder. This happens usually in a different client app than the delegation.

// block height at which to stackconst burnBlockHeight = 2000;
// the delegator initiates a different clientconst delegatorAddress = "ST22X605P0QX2BJC3NXEENXDPFCNJPHE02DTX5V74";
// number cycles to stackconst cycles = 3;
// delegator private key for transaction signingconst delegatorPrivateKey =  "d48f215481c16cbe6426f8e557df9b78895661971d71735126545abddcd5377001";
// the BTC address for reward payouts; either to the delegator or to the BTC address set by the account holder// must start with "1" or "3". Native Segwit (starts with "bc1") is not supportedconst delegatorBtcAddress = "msiYwJCvXEzjgq6hDwD9ueBka6MTfN962Z";
// if you call this method multiple times in the same block, you need to increase the nonce manuallylet nonce = getNonce(delegatorAddress, network);nonce = nonce.add(new BN(1));
const delegatorClient = new StackingClient(delegatorAddress, network);
const delegetateStackResponses = await delegatorClient.delegateStackStx({  stacker: address,  amountMicroStx,  poxAddress: delegatorBtcAddress,  burnBlockHeight,  cycles,  privateKey: delegatorPrivateKey,  nonce, // optional});
//   {//     txid: '0xf6e9dbf6a26c1b73a14738606cb2232375d1b440246e6bbc14a45b3a66618481',//   }

This function calls the delegate-stack-stx method of the Stacking contract to lock up the STX token from the account holder.

The delegator must call this method multiple times (for all stackers), until enough tokens are locked up to participate in Stacking. This is the first part of delegated stacking for the delegator.

info

Reward slots are assigned based on the number of STX tokens locked up for a specific Bitcoin reward address

Step 4: Commit to Stacking#

As soon as pooling completes (minimum STX token threshold reached), the delegator needs to confirm participation for the next one or more cycles:

// reward cycle id to commit toconst rewardCycle = 12;
const delegetateCommitResponse = await delegatorClient.stackAggregationCommit({  poxAddress: delegatorBtcAddress, // this must be the delegator bitcoin address  rewardCycle,  privateKey: delegatorPrivateKey,});
// {//   txid: '0xf6e9dbf6a26c1b73a14738606cb2232375d1b440246e6bbc14a45b3a66618481',// }

This method calls the stack-aggregation-commit function of the Stacking contract. This call also includes locked Stacks from previous cycles. This is the second part of delegated stacking for the delegator.

This method has to be called once for each reward cycle, even if all account holders have already locked their Stacks for several cycles in a row. If no new account holders are added to the pool, then this method call can be made even several cycles before the actual rewards cycle.

Locking delegated Stacks together with a aggregation commits can be done several times before the cycle starts as long as the minimum increment amount of locked Stacks is met.

Congratulations! With the completion of this step, you successfully learnt how to use the Stacking library to ...

Stack STX token on behalf of an account holder
Commit to Stacking with all delegated STX tokens