Transports

Transports are responsible for delivering JSON-RPC requests and responses between the dApp and the wallet extension.

Core interface

import type { RequestPayload, ResponsePayload } from "@sigilry/dapp/messages";

export interface RpcTransport {
  submit(payload: RequestPayload): Promise<ResponsePayload>;
}

WindowTransport

WindowTransport uses window.postMessage for cross-context communication.

import { createCantonClient, WindowTransport } from "@sigilry/dapp";

async function getStatus() {
  const transport = new WindowTransport(window, {
    timeout: 30000,
    targetOrigin: "*",
  });

  const client = createCantonClient(transport);
  return await client.status();
}

getStatus().then(console.log);

Options

• timeout: request timeout in milliseconds (default 30000).
• targetOrigin: postMessage target origin (default *).
• target: optional routing key that addresses one wallet extension when several are installed (default unset). Providers from discovery set it from the wallet’s announcement.

WalletConnectTransport

WalletConnectTransport carries the same JSON-RPC surface over the WalletConnect relay instead of postMessage, for WalletConnect-capable Canton wallets (cross-device, no extension). It requires a WalletConnect Cloud projectId and dApp metadata; see the API reference for the full WalletConnectTransportConfig.

Custom transports

@sigilry/dapp ships only WindowTransport and WalletConnectTransport. For other environments (HTTP, WebSocket, iframe bridges), implement RpcTransport yourself. A minimal HTTP example:

import type { RequestPayload, ResponsePayload } from "@sigilry/dapp/messages";
import type { RpcTransport } from "@sigilry/dapp/transport";

export class HttpTransport implements RpcTransport {
  constructor(private readonly baseUrl: string) {}

  async submit(payload: RequestPayload): Promise<ResponsePayload> {
    const response = await fetch(`${this.baseUrl}/rpc`, {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify(payload),
    });

    if (!response.ok) {
      throw new Error(`HTTP ${response.status}`);
    }

    return (await response.json()) as ResponsePayload;
  }
}