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Endpoints

Enhanced WebSockets are available on mainnet and devnet:
  • Mainnet wss://mainnet.helius-rpc.com/?api-key=<api-key>
  • Devnet wss://devnet.helius-rpc.com/?api-key=<api-key>
WebSockets have a 10-minute inactivity timer; implementing health checks and sending pings every minute is heavily recommended to keep the WebSocket connection alive.

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Authorizations

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api-key
string
required
Your Helius API key. You can get one for free in the dashboard.

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Body

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params
array
required

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Response

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result
integer
Subscription id (needed to unsubscribe)
{
  "jsonrpc": "2.0",
  "id": 420,
  "method": "transactionSubscribe",
  "params": [
    {
      "accountInclude": ["675kPX9MHTjS2zt1qfr1NYHuzeLXfQM9H24wFSUt1Mp8"]
    },
    {
      "commitment": "processed",
      "encoding": "jsonParsed",
      "transactionDetails": "full",
      "showRewards": true,
      "maxSupportedTransactionVersion": 0
    }
  ]
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "transactionSubscribe",
  "params": [
    {
      "accountInclude": ["<WALLET_PUBKEY>"],
      "tokenAccounts": "balanceChanged"
    },
    { "commitment": "confirmed", "encoding": "jsonParsed" }
  ]
}

const WebSocket = require("ws");

const ws = new WebSocket("wss://mainnet.helius-rpc.com/?api-key=<API_KEY>");

ws.on("open", () => {
  ws.send(JSON.stringify({
    jsonrpc: "2.0",
    id: 420,
    method: "transactionSubscribe",
    params: [
      { accountInclude: ["675kPX9MHTjS2zt1qfr1NYHuzeLXfQM9H24wFSUt1Mp8"] },
      {
        commitment: "processed",
        encoding: "jsonParsed",
        transactionDetails: "full",
        maxSupportedTransactionVersion: 0,
      },
    ],
  }));

  // Keep connection alive
  setInterval(() => ws.ping(), 30_000);
});

ws.on("message", (data) => {
  console.log(JSON.parse(data.toString()));
});

{
  "jsonrpc": "2.0",
  "result": 4743323479349712,
  "id": 420
}

{
  "jsonrpc": "2.0",
  "method": "transactionNotification",
  "params": {
    "subscription": 4743323479349712,
    "result": {
      "transaction": {
        "transaction": [
          "Ae6zfSExLsJ/E1+q0jI+3ueAtSoW+6HnuDohmuFwagUo2BU4OpkSdUKYNI1dJfMOonWvjaumf4Vv1ghn9f3Avg0BAAEDGycH0OcYRpfnPNuu0DBQxTYPWpmwHdXPjb8y2P200JgK3hGiC2JyC9qjTd2lrug7O4cvSRUVWgwohbbefNgKQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA0HcpwKokfYDDAJTaF/TWRFWm0Gz5/me17PRnnywHurMBAgIAAQwCAAAAoIYBAAAAAAA=",
          "base64"
        ],
        "meta": {
          "err": null,
          "status": {
            "Ok": null
          },
          "fee": 5000,
          "preBalances": [
            28279852264,
            158122684,
            1
          ],
          "postBalances": [
            28279747264,
            158222684,
            1
          ],
          "innerInstructions": [],
          "logMessages": [
            "Program 11111111111111111111111111111111 invoke [1]",
            "Program 11111111111111111111111111111111 success"
          ],
          "preTokenBalances": [],
          "postTokenBalances": [],
          "rewards": null,
          "loadedAddresses": {
            "writable": [],
            "readonly": []
          },
          "computeUnitsConsumed": 0
        }
      },
      "signature": "5moMXe6VW7L7aQZskcAkKGQ1y19qqUT1teQKBNAAmipzdxdqVLAdG47WrsByFYNJSAGa9TByv15oygnqYvP6Hn2p",
      "slot": 224341380,
      "transactionIndex": 42
    }
  }
}

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Managing Subscriptions

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Subscription IDs

When transactionSubscribe succeeds, the server returns a subscription ID in the result field. This is the same number that appears in params.subscription on every notification from that subscription: 
{
  "jsonrpc": "2.0",
  "result": 4743323479349712,
  "id": 420
}

{
  "jsonrpc": "2.0",
  "method": "transactionNotification",
  "params": {
    "subscription": 4743323479349712,
    "result": {}
  }
}
Store the subscription ID from the response. You need it to unsubscribe.

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Unsubscribing

To stop receiving notifications, call transactionUnsubscribe with the subscription ID. Each transactionSubscribe call on the same connection creates a separate subscription with its own ID, so make sure to unsubscribe before resubscribing to avoid receiving duplicate notifications. 
{
  "jsonrpc": "2.0",
  "id": 421,
  "method": "transactionUnsubscribe",
  "params": [4743323479349712]
}

{
  "jsonrpc": "2.0",
  "result": true,
  "id": 421
}
A few in-flight messages may still arrive briefly after calling transactionUnsubscribe. This is expected behavior.