Architecture
Local-First Signing
Private keys never leave your environment. All order signing happens locally.
Hard-Locked Endpoint
The SDK only communicates with
https://trade.predexon.com. This cannot be overridden.https://trade.predexon.com to prevent man-in-the-middle attacks. A compromised base URL could steal your API key or serve malicious transactions for signing. HTTP redirects are rejected to prevent API key leakage.
Response Validation
The SDK validates server responses before signing to ensure you’re not signing malicious data.Polymarket
- CLOB auth typed data: Domain name, version, and chainId must match expected values
- Redemption transactions: Only whitelisted contract addresses allowed; transactions built locally from server-provided conditionId
- Approval transactions: Chain ID must be Polygon (137), targets restricted to approved USDC and CTF contracts
Kalshi
- Echo validation: Server response must echo back your original ticker, outcome, side, and amount
- Signer validation: Your wallet must be a required signer; no unexpected signers allowed
- Fee payer validation: Must be your wallet or a known sponsor address