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Documentation Index

Fetch the complete documentation index at: https://docs.ostium.com/llms.txt

Use this file to discover all available pages before exploring further.

Use the Ostium app export flow here: app.ostium.com/sdk-export That page creates a delegated gasless SDK setup in the browser:
  • it generates a fresh delegate private key locally in the browser
  • it asks the trader to approve USDC once
  • it registers the derived Safe as the trader’s on-chain delegate
After that, the integration can use createDelegatedAndGasless().

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What the app page gives you

The export flow shows:
  • the trader address
  • the derived smart-account address
  • the registration status and timestamp
  • a ready-to-copy Builder SDK snippet

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SDK snippet

import { OstiumClient } from '@ostium/builder-sdk';

const client = await OstiumClient.createDelegatedAndGasless({
  delegatePrivateKey: '0xYourDelegateKey', // paste the key you saved in step 2
  traderAddress: '0xa02fa4da932f616975f258ce0a9077f8ed3564',
  // pimlicoUrl is optional — defaults to Ostium's sponsored Pimlico bundler on Arbitrum One
  // pimlicoUrl: 'https://builder.ostium.io/v1/pimlico/sponsor?chainId=42161',
  // testnet: true, // Arbitrum Sepolia — uses the 421614 sponsor URL when pimlicoUrl is omitted
  // sponsorshipPolicyId: '...', // optional Pimlico sponsorship policy id
  // rpcUrl: 'https://arb-mainnet.g.alchemy.com/v2/...', // optional; public Arbitrum RPC for reads if omitted
});
The snippet uses a placeholder for the private key. Paste the saved key there and never commit it to source control.

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Flow in the app

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1. Trader address

This is the connected EOA that holds the user’s USDC and positions.

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2. Generate delegate key

Ostium generates a fresh private key in the browser. The user must save it because it cannot be recovered later.

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3. Approve USDC

The trader completes a one-time approval so TradingStorage can move their USDC for SDK trades.

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4. Register delegate

The app registers the derived Safe smart-account address as the trader’s on-chain delegate.

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Why this mode is useful

This flow sets the user up for Delegated + Gasless:
  • trades are signed by the delegate
  • transactions are submitted as sponsored ERC-4337 user operations
  • the SDK can use Ostium’s default Pimlico-compatible sponsor URL when pimlicoUrl is omitted
Read the SDK Overview before integrating if you need the full mode model, helper methods, and trading examples.