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CosmJS examples (testnet)

These snippets use CosmJS to query and sign transactions on Safrochain testnet. They are intentionally minimal and copy/paste friendly.

Prerequisites​

Install deps:

npm i @cosmjs/stargate @cosmjs/proto-signing @cosmjs/encoding

Constants:

export const RPC = "https://rpc.testnet.safrochain.com:443";
export const CHAIN_ID = "safro-testnet-1";
export const DENOM = "usaf";

1) Query: latest height + chain-id​

import { StargateClient } from "@cosmjs/stargate";

const client = await StargateClient.connect(RPC);
const height = await client.getHeight();
const chainId = await client.getChainId();
console.log({ chainId, height });

2) Query: account balance​

import { StargateClient } from "@cosmjs/stargate";

const client = await StargateClient.connect(RPC);
const address = "addr_safro1xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";

const bal = await client.getBalance(address, DENOM);
console.log(bal); // { denom: 'usaf', amount: '...' }

3) Query: validators (basic)​

import { StargateClient } from "@cosmjs/stargate";

const client = await StargateClient.connect(RPC);
const validators = await client.getValidators();

console.log(
  validators.slice(0, 5).map((v) => ({
    moniker: v.description?.moniker,
    operatorAddress: v.operatorAddress,
    jailed: v.jailed,
    tokens: v.tokens,
  })),
);

4) Sign + broadcast: MsgSend​

This signs a transaction using a mnemonic and broadcasts it using the RPC.

import { DirectSecp256k1HdWallet } from "@cosmjs/proto-signing";
import { SigningStargateClient, assertIsDeliverTxSuccess } from "@cosmjs/stargate";

const mnemonic = process.env.MNEMONIC!;
const wallet = await DirectSecp256k1HdWallet.fromMnemonic(mnemonic, {
  prefix: "addr_safro",
});
const [{ address: fromAddress }] = await wallet.getAccounts();

const client = await SigningStargateClient.connectWithSigner(RPC, wallet, {
  gasPrice: { denom: DENOM, amount: "0.05" },
});

const toAddress = "addr_safro1yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy";
const amount = [{ denom: DENOM, amount: "1000" }]; // 1000 usaf

const res = await client.sendTokens(fromAddress, toAddress, amount, "auto", "test send");
assertIsDeliverTxSuccess(res);

console.log({ txHash: res.transactionHash, height: res.height });

Run it:

export MNEMONIC="your 24 word phrase here"
node send.mjs

Notes​

  • Fees: the examples use gasPrice amount 0.05 in usaf (0.05 usaf per gas) plus "auto" gas simulation.
  • Prefix: wallet prefix must be addr_safro.
  • Production apps should add retries/backoff and handle RPC failures gracefully.
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