Sign Transactions on NEAR

const response = await circleDeveloperSdk.createWallets({
  accountType: 'EOA',
  blockchains: ['NEAR-TESTNET'],
  count: 2,
  walletSetId: '<wallet-set-id>',
})

import { initiateDeveloperControlledWalletsClient } from '@circle-fin/developer-controlled-wallets'
import { connect, utils } from 'near-api-js'
import { baseDecode, baseEncode } from '@near-js/utils'
import { PublicKey } from '@near-js/crypto'
import {
  createTransaction,
  actionCreators,
  encodeTransaction,
} from '@near-js/transactions'
import axios from 'axios'
import fs from 'fs'

const NEAR_CONFIG = {
  networkId: 'testnet',
  nodeUrl: 'https://rpc.testnet.near.org',
}

// fill in these variables
const CIRCLE_API_KEY = ''
const CIRCLE_ENTITY_SECRET = ''
const CIRCLE_WALLET_PUBLIC_KEY = '' // with `ed25519:` scheme
const CIRCLE_WALLET_ID = ''
const CIRCLE_TX_MEMO = ''
const MASTER_ACCOUNT = ''
const RECEIVER = ''
const AMOUNT = '0.001'

async function main() {
  const client = initiateDeveloperControlledWalletsClient({
    apiKey: CIRCLE_API_KEY,
    entitySecret: CIRCLE_ENTITY_SECRET,
  })

  try {
    // setup client and account
    const near = await connect({ ...NEAR_CONFIG })
    const sender = await near.account(MASTER_ACCOUNT)

    // get latest finalized block
    const block = await near.connection.provider.block({ finality: 'final' })
    const blockHash = block.header.hash

    // get sender nonce
    const senderAccessKey = await sender.getAccessKeys()
    let nonce = BigInt(0)
    for (let i = 0; i < senderAccessKey.length; i++) {
      if (senderAccessKey[i].public_key === CIRCLE_WALLET_PUBLIC_KEY) {
        nonce = senderAccessKey[i].access_key.nonce + BigInt(1)
      }
    }
    if (nonce === BigInt(0)) {
      console.error(
        `couldn't find corresponding access key: ${CIRCLE_WALLET_PUBLIC_KEY}`,
      )
      return
    }

    // build raw transaction
    const actions = [
      actionCreators.transfer(
        BigInt(utils.format.parseNearAmount(AMOUNT) || 0),
      ),
    ]
    const signerPublicKey = PublicKey.fromString(CIRCLE_WALLET_PUBLIC_KEY)
    const transaction = createTransaction(
      MASTER_ACCOUNT,
      signerPublicKey,
      RECEIVER,
      nonce,
      actions,
      baseDecode(blockHash),
    )

    // serialize borsh
    const message = encodeTransaction(transaction)

    // base64 encode
    const base64EncodedTx = Buffer.from(message).toString('base64')

    // call Circle's API to sign tx
    const signedTx = await client.signTransaction({
      walletId: CIRCLE_WALLET_ID,
      rawTransaction: base64EncodedTx,
      memo: CIRCLE_TX_MEMO,
    })
  } catch (err) {
    if (axios.isAxiosError(err)) {
      console.error(`status: ${err.response?.status}`)
      console.error(`data: `, err.response?.data)
    } else {
      console.error(`unknown err: `, err)
    }
  }
}

;(async () => {
  await main()
})()