Self + Self - Ostium

createSelfAndSelf() is the simplest mode.

the trader EOA owns USDC and positions
the same trader EOA signs transactions
transactions are submitted directly on Arbitrum and the trader pays gas

When to use it

bots and scripts
server-side systems trading a house account
wallet-driven apps where the user is comfortable paying gas
client-side apps that only need unsigned EOA transaction payloads

Submit-capable client

const client = await OstiumClient.createSelfAndSelf({
  traderPrivateKey: process.env.TRADER_PRIVATE_KEY as `0x${string}`,
  rpcUrl: process.env.ARB_RPC_URL!,
});

Build-only client

const client = await OstiumClient.createSelfAndSelf({
  traderAddress: '0xTraderAddress',
});

const tx = client.getOpenTradeTx({
  pairId: 0,
  buy: true,
  price: '65000',
  collateral: '100',
  leverage: '5',
  type: OrderType.Market,
});

In build-only mode, get*Tx() returns an EOA request with from, to, data, and value so your app can pass it to a wallet for signing.

Parameters

Field	Type	Required	Notes
`traderPrivateKey`	`0x${string}`	Submit-capable	Trader EOA key. Holds USDC, owns positions, pays gas.
`traderAddress`	`0x${string}`	Build-only	Trader EOA address (no key).
`rpcUrl`	`string`	Submit-capable; optional for build-only	Arbitrum RPC URL. Build-only defaults to the public RPC.

Plus the shared options (testnet, slippageBps, builder, subgraphUrl, builderApiUrl, alchemyApiKey). See Client Configuration.

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