SDK walkthrough, part 1 of 3

SDK quickstart

From an empty folder to a transfer sent from your own code.

The SDK is the same package as the CLI, @arxiumlabs/sdk. It has no runtime dependencies and runs in Node, browsers and Workers. These pages use plain JavaScript files run with Node, so there's nothing to compile.

Before you start

Node 20 or later.
An API key from Endpoints and API keys.
A Console key holding test ARX: sign in at the Console, generate a key under Settings, claim ARX under Faucet, then click Export encrypted key.

1. Create a project

Terminal

mkdir my-arxium-app && cd my-arxium-appnpm init -ynpm pkg set type=modulenpm install @arxiumlabs/sdk

Move the exported key file into the folder, then set the same variables the CLI uses:

Terminal

export ARX_RPC=https://retracer-api.arxium.network/rpc/corechain-devnetexport ARX_TOKEN=rk_...export ARX_KEY=arxium-devnet-key-xxxxxxxx.jsonexport ARX_PASSPHRASE=...           # the key's passphrase

2. Connect and unlock your key

Every script in this walkthrough imports this one file:

arxium.mjs

// Shared by every script: one client, your key, and a send() that signs, submits and waits.import { readFile } from "node:fs/promises";import { ArxiumRpc, unlockKey } from "@arxiumlabs/sdk"; export const rpc = new ArxiumRpc({ rpc: process.env.ARX_RPC, token: process.env.ARX_TOKEN });export const me = JSON.parse(await readFile(process.env.ARX_KEY, "utf8")); // the key file exported from the Consoleconst privateKey = await unlockKey(me, process.env.ARX_PASSPHRASE); export const send = (payload) => rpc.sendAction({ privateKey, sender: me.address, payload });

unlockKey decrypts the key in memory with WebCrypto. The key and passphrase never leave your machine. send fetches your nonce, signs locally, submits the action and waits until it's in a block. In a real app, load the passphrase from a secret store rather than the environment.

3. Read a balance and send ARX

send.mjs

import { arxToIum, encodeTransfer, iumToArx } from "@arxiumlabs/sdk";import { me, rpc, send } from "./arxium.mjs"; const account = await rpc.account(me.address);console.log(`${me.address} holds ${iumToArx(BigInt(account.balance))} ARX`); const { action, status } = await send(encodeTransfer(process.argv[2], arxToIum("1")));console.log(`${status.status} at height ${status.height}, signature ${action.signature.slice(0, 16)}…`);

Pass any address, such as a second Console account's:

Terminal

node send.mjs arx1urfs...arx1k29t… holds 10 ARXconfirmed at height 11, signature b41d56b8ba908cee…

Each encode… function builds one action's payload, and send does the rest. Amounts are bigint base units: arxToIum("1") is 1_000_000_000n. If the chain refuses an action, send throws an ActionDroppedError carrying the node's reason. Part 3 turns that into a message for your user.