Delegated + Gasless

createDelegatedAndGasless() is the most operationally advanced mode.

the trader EOA owns USDC and positions
a delegate EOA signs the delegated action
the delegate’s Safe submits it as a sponsored user operation

When to use it

backend-driven products that want custody separation and gasless submission
high-volume builder integrations
systems that already operate a Safe or Pimlico flow

One-time trader setup

The trader must approve USDC and register the delegate Safe, not the delegate EOA:

await traderClient.approveUsdc('max');
await traderClient.setDelegate('0xDelegateSafeAddress');

You can get that Safe address from client.getSmartAccountAddress().

Submit-capable client

const client = await OstiumClient.createDelegatedAndGasless({
  delegatePrivateKey: process.env.DELEGATE_PRIVATE_KEY as `0x${string}`,
  traderAddress: '0xTraderAddress',
  pimlicoUrl: 'https://builder.prod.bedrock.ostium.io/v1/pimlico/sponsor?chainId=42161',
});

If you already know the Safe address for this delegate key and chain, pass safeAddress to skip the SDK’s smart-account derivation call during construction:

const client = await OstiumClient.createDelegatedAndGasless({
  delegatePrivateKey: process.env.DELEGATE_PRIVATE_KEY as `0x${string}`,
  traderAddress: '0xTraderAddress',
  safeAddress: '0xDelegateSafeAddress',
});

Build-only client

const client = await OstiumClient.createDelegatedAndGasless({
  traderAddress: '0xTraderAddress',
  delegateAddress: '0xDelegateAddress',
  safeAddress: '0xDelegateSafeAddress',
});

In build-only mode, get*Tx() returns a Safe-style request whose call data is already wrapped for delegated execution.

Parameters

Field	Type	Required	Notes
`delegatePrivateKey`	`0x${string}`	Submit-capable	Delegate EOA key. A Safe is derived from it and submits via Pimlico.
`traderAddress`	`0x${string}`	Yes	Trader the delegate acts for. Must have called `setDelegate(safeAddress)` with the derived Safe (`client.getSmartAccountAddress()`).
`delegateAddress`	`0x${string}`	Build-only	Delegate EOA that owns the Safe.
`safeAddress`	`0x${string}`	Build-only; optional submit-capable	Required for build-only. Optional with `delegatePrivateKey` when you already know the deterministic Safe address and want to skip derivation.
`pimlicoUrl`	`string`	Optional	Bundler/paymaster URL. Defaults to the Ostium sponsor URL (chain-aware).
`rpcUrl`	`string`	Optional	RPC URL for reads/simulation. Defaults to the public RPC.
`sponsorshipPolicyId`	`string`	Optional	Pimlico sponsorship policy ID.

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

SDK

Client Modes

Helpers

Read Methods

Write Methods

Builder API

Builder

Trader

Legacy

Delegated + Gasless

When to use it

One-time trader setup

Submit-capable client

Build-only client

Parameters

​When to use it

​One-time trader setup

​Submit-capable client

​Build-only client

​Parameters

When to use it

One-time trader setup

Submit-capable client

Build-only client

Parameters