Streams API

Handshake auth, stream endpoints, and message shapes for live pending transactions, new blocks, and logs.

The Streams API is available at:

wss://streams-<endpoint>.evmkit.app/

Replace <endpoint> with your chosen regional endpoint. See Regions for hostname patterns and the current regional layout.

For pricing, use the single table on the Billing & CU pricing page.

Open a separate websocket connection for each stream endpoint.

Pending transactions stream:

wss://streams-<endpoint>.evmkit.app/pending-txs

Pending logs stream:

wss://streams-<endpoint>.evmkit.app/pending-logs

New blocks stream:

wss://streams-<endpoint>.evmkit.app/new-blocks

Authentication

Auth happens during the websocket handshake.

Required header:

X-Api-Key: evk_your_live_key

First message

After a successful handshake, the first message is:

{"event":"subscribed"}

Transaction message

{
  "event": "transaction",
  "source": "pending-txs",
  "received_at": 1741800000000,
  "raw": {
    "hash": "0xb63b98c8db16666bdc322df84e10c1328d1036bf27e7f07910490349a7884667",
    "from": "0x6cdb7776f6a20b9ed4441b791e9541a6fc04e313",
    "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
    "input": "0xa9059cbb...",
    "value": "0x0"
  }
}

Block message

{
  "event": "block",
  "source": "new-blocks",
  "received_at": 1741800000000,
  "raw": {
    "hash": "0xblockhash",
    "parentHash": "0xparenthash",
    "number": "0x123456",
    "timestamp": "0x67d3b5a4",
    "miner": "0x0000000000000000000000000000000000000000"
  }
}

raw contains the block payload published on the stream.

Logs message

{
  "event": "pending_logs",
  "source": "pending-logs",
  "received_at": 1741800000000,
  "trigger": {
    "raw": "0x02f8728201..."
  },
  "tx_hash": "0xtransactionhash",
  "pending_block": 12345678,
  "logs": [
    {
      "address": "0xpool",
      "topics": ["0xtopic0", "0xtopic1"],
      "data": "0xdeadbeef"
    }
  ]
}

logs contains a best-effort pending log view associated with the streamed transaction. It is not a canonical on-chain log stream. trigger mirrors the originating transaction: raw mempool events expose raw, while auction-backed events expose source, from, to, data, and value.

Pricing

Use the single pricing table on the Billing & CU pricing page. The Streams API is billed per connection and per published event.