Messages
{
"action": "<string>",
"chain_id": 123,
"dataset_id": "<string>",
"params": {
"contract_address": "<string>"
}
}{
"action": "<string>",
"chain_id": 123,
"dataset_id": "<string>"
}No examples foundNo examples found{
"chain_id": 123,
"dataset_id": "<string>",
"is_reorg": true,
"data": {
"contract_address": "<string>",
"name": "<string>",
"symbol": "<string>",
"token_uri": "<string>",
"block_number": 123,
"_tracing_id": "<string>"
}
}Entities
ERC-721 Tokens
Subscribe to real-time ERC-721 collection registry updates.
WSS
/
Overview
- Dataset ID:
0202 - ERC-721 Tokens - Description: Catalog of ERC-721 NFT collection contracts (EIP-721).
- Sample: Hugging Face Sample
Subscription Parameters
string
Optional filter: one collection contract (20-byte hex, no
0x prefix).Message Fields
string
Unique contract incarnation ID (26 bytes hex).
string
Collection contract address (20-byte hex).
number
Block where the collection was first recognized.
string
Block time (ISO-8601).
number
Transaction index within the block.
string | null
Collection name from
name() (ERC721Metadata, optional).string | null
Collection symbol from
symbol() (ERC721Metadata, optional).string | null
Representative sample from the discovery probe.
boolean | null
Whether the contract supports the ERC721Metadata extension; null when detection was via fallback.
boolean | null
Whether the contract supports the ERC721Enumerable extension; null when detection was via fallback.
string
Lineage id (hex).
string[]
Parent lineage ids (hex).
string
Record creation time (ISO-8601).
string
Record last update time (ISO-8601).
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": "0202", "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 + 1024];
unsigned char *p = &buf[LWS_PRE];
size_t n = sprintf((char *)p, "{\"action\": \"subscribe\", \"dataset_id\": \"0202\", \"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\": \"0202\", \"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": "0202",
"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: '0202',
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": "0202", "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": "0202",
"is_reorg": false,
"data": {
"contract_id": "bc4ca0eda7647a8ab7c2061c2e118a18a936f13d00bb875f0074",
"contract_address": "bc4ca0eda7647a8ab7c2061c2e118a18a936f13d",
"block_number": 12287507,
"block_time": "2021-04-22T23:43:17Z",
"tx_index": 114,
"name": "BoredApeYachtClub",
"symbol": "BAYC",
"token_uri": "ipfs://QmeSjSinHpPnmXmspMjwiXyN6zS4E9zccariGR3jxcaWtq/",
"supports_metadata": true,
"supports_enumerable": true,
"_tracing_id": "020200000000000000000000000000000001",
"_parent_tracing_ids": ["010300000000000000000000000000000001"],
"_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": {
"contract_address": "<string>"
}
}{
"action": "<string>",
"chain_id": 123,
"dataset_id": "<string>"
}No examples foundNo examples found{
"chain_id": 123,
"dataset_id": "<string>",
"is_reorg": true,
"data": {
"contract_address": "<string>",
"name": "<string>",
"symbol": "<string>",
"token_uri": "<string>",
"block_number": 123,
"_tracing_id": "<string>"
}
}subscribe
type:object
unsubscribe
type:object
subscribe_response
type:object
unsubscribe_response
type:object
update
type:object
Last modified on July 19, 2026
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