Browser dApps & wallets

A dApp holds no key — the user's wallet does. The BKC Wallet browser extension injects a Keplr-compatible provider (window.keplr), and the SDK turns it into the same ethers Signer the rest of these docs use.

Connect

import { connectBkcWallet, Contract } from "@bkc-network-lib/sdk";

const endpoints = {
  evmRpcUrl: "https://rpc.bkc.network",
  cosmosRpcUrl: "https://comet-rpc.bkc.network",
};

const { account, signer, provider, cosmosSigner, wallet } = await connectBkcWallet(endpoints);
// account.address     bkc1…   the Cosmos address
// account.evmAddress  0x…     the same account, as the EVM sees it

Returned	Use it for
signer	Contract, ContractFactory — writes are signed by the wallet with ML-DSA-65
provider	reads
cosmosSigner	the same account as an OfflineDirectSigner, for SigningStargateClient
wallet	the raw injected provider (e.g. signArbitrary)

connectBkcWallet(endpoints, { chainId, timeoutMs }): chainId is the identifier passed to the wallet's enable()/getKey() (default "BKC"); timeoutMs is how long to wait for the extension to inject itself (default 3 s). If no wallet appears it throws No BKC wallet found. Install the extension and reload the page.

A full interaction

const { account, signer } = await connectBkcWallet(endpoints);
const counter = new Contract(address, abi, signer);

console.log(await counter.get());     // read — no wallet prompt

const tx = await counter.set(42);     // write — the wallet asks the user to approve
const receipt = await tx.wait();
console.log(receipt.hash, receipt.logs);

Design around two chain facts

• Gas is higher than on an EVM chain. An ML-DSA-65 signature is ~3.3 KB and gas is per byte; budget from bkcChain.baseGasLimit.
• Gas cannot be simulated (bkcChain.isSimulable === false); the estimate comes from the budget, not the node.

And: receipt.fee is 0 — show getEvmTransactionCost() instead if you display fees.

Sign-in with a BKC account

signer.signMessage() cannot work (no ECDSA key). Use ADR-36 signing through the wallet and verify on your backend with verifyMessage(), or inside a contract through the ML-DSA verify precompile.

Endpoints from the browser

All public endpoints send Access-Control-Allow-Origin: *, including the EVM WebSocket (wss://ws.bkc.network), so a page can subscribe to newHeads directly. Wrapped-call logs are not pushed over eth_subscribe("logs"); poll eth_getLogs for contract events.