Our WebSocket API allows developers to receive Real-Time notifications about new transactions and blocks. The Websocket echo test can be useful for debugging.

Connection URL:


Once the socket is open you can subscribe to a channel by sending an "op" message.



Subscribing to Unconfirmed transactions

Subscribe to notifications for all new bitcoin transactions.




Subscribing to an Address

Receive new transactions for a specific bitcoin address:

{"op":"addr_sub", "addr":"$bitcoin_address"}


{"op":"addr_unsub", "addr":"$bitcoin_address"}

Message on new transaction:

    "op": "utx",
    "x": {
        "lock_time": 0,
        "ver": 1,
        "size": 192,
        "inputs": [
                "sequence": 4294967295,
                "prev_out": {
                    "spent": true,
                    "tx_index": 99005468,
                    "type": 0,
                    "addr": "1BwGf3z7n2fHk6NoVJNkV32qwyAYsMhkWf",
                    "value": 65574000,
                    "n": 0,
                    "script": "76a91477f4c9ee75e449a74c21a4decfb50519cbc245b388ac"
                "script": "483045022100e4ff962c292705f051c2c2fc519fa775a4d8955bce1a3e29884b2785277999ed02200b537ebd22a9f25fbbbcc9113c69c1389400703ef2017d80959ef0f1d685756c012102618e08e0c8fd4c5fe539184a30fe35a2f5fccf7ad62054cad29360d871f8187d"
        "time": 1440086763,
        "tx_index": 99006637,
        "vin_sz": 1,
        "hash": "0857b9de1884eec314ecf67c040a2657b8e083e1f95e31d0b5ba3d328841fc7f",
        "vout_sz": 1,
        "relayed_by": "",
        "out": [
                "spent": false,
                "tx_index": 99006637,
                "type": 0,
                "addr": "1A828tTnkVFJfSvLCqF42ohZ51ksS3jJgX",
                "value": 65564000,
                "n": 0,
                "script": "76a914640cfdf7b79d94d1c980133e3587bd6053f091f388ac"

Subscribing to new Blocks

Receive notifications when a new block is found. Note: if the chain splits you will receive more than one notification for a specific block height.




Message On New Block:

    "op": "block",
    "x": {
        "txIndexes": [
        "nTx": 0,
        "totalBTCSent": 0,
        "estimatedBTCSent": 0,
        "reward": 0,
        "size": 0,
        "blockIndex": 190460,
        "prevBlockIndex": 190457,
        "height": 170359,
        "hash": "00000000000006436073c07dfa188a8fa54fefadf571fd774863cda1b884b90f",
        "mrklRoot": "94e51495e0e8a0c3b78dac1220b2f35ceda8799b0a20cfa68601ed28126cfcc2",
        "version": 1,
        "time": 1331301261,
        "bits": 436942092,
        "nonce": 758889471

Debugging OPs:


Responds with the latest block


Responds with the latest transaction. If subscribed to any addresses it will respond with the latest transaction involving those addresses.