Extended
| Property | Value |
|---|---|
| Transport | REST (orders) + WebSocket (market data + account stream) |
| Signing | SNIP-12 (Stark) |
| Funding interval | 1 hour |
| Concurrent Spreadr maker trades | 3 per account (subject to change) |
| Builder code support | ✅ — 0.5 bp via builder client ID |
Account setup
Extended uses a Vault model: your trading happens against a Stark position ID derived from your wallet, and orders are signed with a Stark key — separate from your wallet's normal key. Spreadr derives and registers all of this for you.
Open an account
Visit extended.exchange (opens in a new tab) and connect your wallet. Deposit USDC.
Connect in Spreadr
In the terminal: Settings → Wallets, pick your wallet, then + Extended → Connect Extended. Spreadr derives your Stark key in the browser, registers the account, and creates the API key — you sign 4 messages along the way: key derivation, account registration, API key creation, and the credential vault unlock. Nothing to copy or paste.
Quirks
- REST-based orders. Unlike HL/Lighter, Extended doesn't accept orders over WebSocket. Spreadr sends orders one per call, throttled within the rate budget.
- Market maker status — if you trade meaningful volume on Extended, you can apply to Extended directly for market-maker status, which raises your account's rate limits substantially and lets Spreadr be more responsive.
- Funding settles every hour — finer-grained than most venues. Net-funding arb opportunities can flip more often.
Builder fees
Spreadr is registered as an Extended builder, taking 0.5 bp (0.00005 fraction) on each fill it routes for you. Shows on Extended's side as builder fee.
Common errors
| Symptom | Cause | Fix |
|---|---|---|
| "Invalid Stark signature" | Stale or corrupted credentials | Delete the Extended credential in Spreadr and reconnect |
| "Rate limit exceeded" | Sustained high request volume on your Extended account | Reduce concurrent active spreads, or apply for MM status |
| "Insufficient collateral" | Position size > available margin | Deposit USDC or reduce leverage |
| Trade stuck at "pending" | Signing failure on first order | Almost always stale credentials. Delete + reconnect. |