Cosmos side (bank, staking, gov)

Native transfers, staking and governance are Cosmos messages, not EVM calls. The SDK includes the CometBFT/Cosmos client (the CosmJS fork) with ML-DSA-65 wallets.

Wallet and client

import {
  DirectMldsa65HdWallet,
  SigningStargateClient,
  GasPrice,
  calculateFee,
  makeBkcRegistry,
} from "@bkc-network-lib/sdk";

const wallet = await DirectMldsa65HdWallet.fromMnemonic(mnemonic, { prefix: "bkc" });
const [{ address }] = await wallet.getAccounts();

const client = await SigningStargateClient.connectWithSigner(
  "https://comet-rpc.bkc.network",
  wallet,
  { registry: makeBkcRegistry() },   // registers /bkc.bkc.v1.* alongside the standard Cosmos types
);

DirectMldsa65HdWallet derives keys from the mnemonic with BKC's HKDF scheme (see Accounts & keys); DirectMldsa65Wallet.fromSeed(seed, "bkc") takes a 32-byte seed.

Fees: always explicit

BKC cannot simulate transactions (it rejects SIGN_MODE_UNSPECIFIED), so "auto" gas does not work. Give every transaction a gas budget:

const gasPrice = GasPrice.fromString("5000000bkc");
const fee = calculateFee(300_000, gasPrice);   // a send uses ~257k gas

Send BKC

const result = await client.sendTokens(
  address,
  "bkc1recipient…",
  [{ denom: "bkc", amount: "1000000000000000000" }],   // 1 BKC (18 decimals)
  fee,
);
console.log(result.transactionHash, result.code); // code 0 = success

A bank MsgSend moves the same balance an EVM transfer does, but Blockscout indexes the EVM side: a Cosmos send does not get its own page on the explorer. For transfers users will look up, send over the EVM (signer.sendTransaction({ to, value })).

Staking

await client.delegateTokens(address, "bkcvaloper1…", { denom: "bkc", amount: "1000000000000000000" },
  calculateFee(500_000, gasPrice));

await client.undelegateTokens(address, "bkcvaloper1…", { denom: "bkc", amount: "1000000000000000000" },
  calculateFee(500_000, gasPrice));      // ~447k gas measured

await client.withdrawRewards(address, "bkcvaloper1…", calculateFee(400_000, gasPrice));

Governance

Proposals and votes are standard x/gov messages, signed with the same client. Deposits on BKC are scaled for 18 decimals: the minimum deposit is 10 BKC (expedited: 50 BKC), and a proposal must be submitted with at least 25% of it.

Queries

Read-only queries need no signer:

import { StargateClient } from "@bkc-network-lib/sdk";

const ro = await StargateClient.connect("https://comet-rpc.bkc.network");
await ro.getBalance("bkc1…", "bkc");
await ro.getChainId();   // "bkc-testnet"

or use the REST endpoint directly — see REST & gRPC.

Custom message types

To add a chain module of your own to the registry, follow CUSTOM_PROTOBUF_CODECS.md in packages/stargate of bkc-lib.