Messages
{
"action": "<string>",
"chain_id": 123,
"dataset_id": "<string>",
"params": {}
}{
"action": "<string>",
"chain_id": 123,
"dataset_id": "<string>"
}No examples foundNo examples found{
"chain_id": 123,
"dataset_id": "<string>",
"is_reorg": true,
"data": {
"block_number": 123,
"block_hash": "<string>",
"parent_block_hash": "<string>",
"miner": "<string>",
"timestamp_utc": "<string>",
"_tracing_id": "<string>"
}
}Primitives
Blocks
Subscribe to real-time canonical EVM block headers and integrity metadata.
WSS
/
Overview
- Dataset ID:
0101 - Blocks - Description: Canonical block headers with BlockDB integrity metadata.
- Sample: Hugging Face Sample
Subscription Parameters
Message Fields
Each message in the stream follows the standard block schema:Sequential block height.
Keccak-256 hash of the block header (32 bytes, hex string, no
0x prefix).Keccak-256 hash of the parent block.
Fee recipient / coinbase address.
Timestamp when the block was mined.
Tracing identifier for the canonical block record.
If
true, this message is a reorg correction and should be treated as an overwrite of previously emitted state at the same natural key (for blocks: block_number).Subscription Example
# Use wscat to connect and subscribe
wscat -c wss://api.blockdb.io/v1/evm/ \
-H "Authorization: Bearer $BLOCKDB_API_KEY" \
-x '{"action": "subscribe", "dataset_id": "0101", "chain_id": 1, "params": {}}'
#include <libwebsockets.h>
#include <string.h>
#include <stdio.h>
static int callback_blockdb(struct lws *wsi, enum lws_callback_reasons reason,
void *user, void *in, size_t len) {
switch (reason) {
case LWS_CALLBACK_CLIENT_ESTABLISHED:
lws_callback_on_writable(wsi);
break;
case LWS_CALLBACK_CLIENT_RECEIVE:
printf("Received: %s\n", (char *)in);
break;
case LWS_CALLBACK_CLIENT_WRITEABLE: {
unsigned char buf[LWS_PRE + 512];
unsigned char *p = &buf[LWS_PRE];
size_t n = sprintf((char *)p, "{\"action\": \"subscribe\", \"dataset_id\": \"0101\", \"chain_id\": 1, \"params\": {}}");
lws_write(wsi, p, n, LWS_WRITE_TEXT);
break;
}
}
return 0;
}
using System;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
class Program {
static async Task Main() {
using var ws = new ClientWebSocket();
ws.Options.SetRequestHeader("Authorization", $"Bearer {Environment.GetEnvironmentVariable("BLOCKDB_API_KEY")}");
await ws.ConnectAsync(new Uri("wss://api.blockdb.io/v1/evm/"), CancellationToken.None);
var subMsg = "{\"action\": \"subscribe\", \"dataset_id\": \"0101\", \"chain_id\": 1, \"params\": {}}";
await ws.SendAsync(new ArraySegment<byte>(Encoding.UTF8.GetBytes(subMsg)), WebSocketMessageType.Text, true, CancellationToken.None);
var buffer = new byte[1024 * 4];
while (ws.State == WebSocketState.Open) {
var result = await ws.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
Console.WriteLine(Encoding.UTF8.GetString(buffer, 0, result.Count));
}
}
}
import websocket
import json
import os
def on_message(ws, message):
print(f"Received: {message}")
def on_open(ws):
msg = {
"action": "subscribe",
"dataset_id": "0101",
"chain_id": 1,
"params": {}
}
ws.send(json.dumps(msg))
ws = websocket.WebSocketApp(
"wss://api.blockdb.io/v1/evm/",
header={"Authorization": f"Bearer {os.getenv('BLOCKDB_API_KEY')}"},
on_message=on_message,
on_open=on_open
)
ws.run_forever()
const WebSocket = require('ws');
const ws = new WebSocket('wss://api.blockdb.io/v1/evm/', {
headers: { 'Authorization': `Bearer ${process.env.BLOCKDB_API_KEY}` }
});
ws.on('open', () => {
ws.send(JSON.stringify({
action: 'subscribe',
dataset_id: '0101',
chain_id: 1,
params: {}
}));
});
ws.on('message', (data) => {
console.log('Received:', JSON.parse(data));
});
package main
import (
"fmt"
"log"
"net/http"
"os"
"github.com/gorilla/websocket"
)
func main() {
header := http.Header{"Authorization": []string{"Bearer " + os.Getenv("BLOCKDB_API_KEY")}}
c, _, err := websocket.DefaultDialer.Dial("wss://api.blockdb.io/v1/evm/", header)
if err != nil {
log.Fatal("dial:", err)
}
defer c.Close()
sub := `{"action": "subscribe", "dataset_id": "0101", "chain_id": 1, "params": {}}`
err = c.WriteMessage(websocket.TextMessage, []byte(sub))
if err != nil {
log.Fatal("write:", err)
}
for {
_, message, err := c.ReadMessage()
if err != nil {
log.Fatal("read:", err)
}
fmt.Printf("Received: %s\n", message)
}
}
Response Example
{
"chain_id": 1,
"dataset_id": "0101",
"is_reorg": false,
"data": {
"block_number": 12345678,
"block_hash": "7b5c0972efb6a0b5be4a4d4a0de5d1abd922478a53f32b2c717a800c862ba9e0",
"parent_block_hash": "f78e26c5959a94d6a62ed3837f5dcecf0d3761bf0a502e12a08fd7bc44c8568d",
"receipt_root": "b4d8cfe4b87590afe7ed95fbf7798142e8fb1ce86307ff0eb6580b8bc23de92f",
"miner": "0000000000000000000000000000000000000000",
"gas_limit": 30000000,
"extra_data": "636c61737369635f657468657265756d",
"size": 124836,
"timestamp_utc": "2025-11-11T18:42:15.123Z",
"_tracing_id": "010200000000000000000000000000000000",
"_computed_receipt_root": "b4d8cfe4b87590afe7ed95fbf7798142e8fb1ce86307ff0eb6580b8bc23de92f",
"_computed_receipt_timestamp_utc": "2025-11-11T18:43:00.000Z",
"_created_at": "2025-11-11T18:42:15.123Z",
"_updated_at": "2025-11-11T18:42:15.123Z"
}
}
Messages
{
"action": "<string>",
"chain_id": 123,
"dataset_id": "<string>",
"params": {}
}{
"action": "<string>",
"chain_id": 123,
"dataset_id": "<string>"
}No examples foundNo examples found{
"chain_id": 123,
"dataset_id": "<string>",
"is_reorg": true,
"data": {
"block_number": 123,
"block_hash": "<string>",
"parent_block_hash": "<string>",
"miner": "<string>",
"timestamp_utc": "<string>",
"_tracing_id": "<string>"
}
}subscribe
type:object
unsubscribe
type:object
subscribe_response
type:object
unsubscribe_response
type:object
update
type:object
Last modified on April 6, 2026
Was this page helpful?
⌘I