Blockchain.com WebSocket-API

uses
  sgcWebSocket, sgcJSON;

var
  WSClient: TsgcWebSocketClient;
begin
  WSClient := TsgcWebSocketClient.Create(nil);
  WSClient.URL := 'wss://ws.blockchain.info/inv';

  WSClient.OnMessage := procedure(Connection: TsgcWSConnection; const Text: string)
  begin
    Memo1.Lines.Add(Text);
  end;

  WSClient.OnConnect := procedure(Connection: TsgcWSConnection)
  begin
    // Subscribe to all new bitcoin transactions
    Connection.WriteData('{"op":"unconfirmed_sub"}');

    // Receive new blocks
    Connection.WriteData('{"op":"blocks_sub"}');

    // Subscribe to a specific address
    Connection.WriteData('{"op":"addr_sub","addr":"1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"}');
  end;

  WSClient.Active := True;
end;