Read-only - Ostium

createReadOnly() is the no-signing, no-submission mode.

no private key
no signer
no transaction building
all read methods available

When to use it

price widgets
charts and dashboards
analytics tools
account views that display positions, orders, fills, or candles

Example

const client = await OstiumClient.createReadOnly();

const { pairs } = await client.getPairs();
const { prices } = await client.getAllPrices();
const positions = await client.getOpenPositions({ user: '0xTraderAddress' });

For low-latency account snapshots, pass user and an Alchemy key:

const stream = client.streamAccountUpdates({
  user: ['0xTraderAddress'],
  alchemyApiKey: process.env.ALCHEMY_API_KEY!,
});

Write methods throw INVALID_CONFIG in this mode.

Parameters

All fields are optional.

Field	Type	Default	Notes
`rpcUrl`	`string`	public RPC	Arbitrum RPC URL for reads/simulation.
`testnet`	`boolean`	`false`	Use Arbitrum Sepolia.
`subgraphUrl`	`string`	mainnet/testnet subgraph	Override the subgraph endpoint.
`builderApiUrl`	`string`	`https://builder.ostium.io`	Override the builder API base URL.
`alchemyApiKey`	`string`	—	Required only to start `streamAccountUpdates()`.

Read-only clients do not accept slippageBps or builder. See Client Configuration for the full reference.

Delegated + Gasless Testnet

⌘I

​When to use it

​Example

​Parameters

When to use it

Example

Parameters