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Overview

Predexon Trading API manages wallets on behalf of users. Instead of requiring users to handle private keys, manage gas, or sign transactions, the API handles all of this automatically.

Simplified Integration

No wallet SDKs or key management needed in your application

Gasless Trading

Polymarket trades use gasless relay - no POL required

Multi-Venue

Single API for trading on Polymarket (Polygon) and Kalshi (Solana)

Secure Key Management

Private keys managed by Turnkey - you never handle them

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How It Works

  1. Your Application calls the Predexon Trading API
  2. Predexon API manages user wallets and executes trades
  3. Venues settle transactions on their respective blockchains

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Wallet Management

When you create a user, the API generates managed wallets for each venue:
VenueDeposit AddressBlockchain
PolymarketpolymarketWalletAddressPolygon (USDC.e)
KalshikalshiWalletAddressSolana (USDC + SOL)
Send USDC.e to Polygon for Polymarket, or USDC on Solana (plus SOL for fees) for Kalshi. The API handles all transaction signing automatically.

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Key Security

Private keys are managed by Turnkey, a secure key management infrastructure:
  • Predexon never sees private keys - keys are generated and stored in Turnkey’s secure environment
  • Hardware-backed security - keys never leave secure enclaves
  • No key management in your app - all signing happens server-side

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Order Execution

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Polymarket Orders

Polymarket uses an orderbook: Order Types:
  • Limit Orders: Placed on the orderbook at a specific price, wait for a counterparty
  • Market Orders: Execute immediately at the best available price
Execution Model:
  • Orders can be partially filled
  • Open orders can be cancelled
  • Gasless relay means no POL needed

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Kalshi Orders

Kalshi orders execute atomically: Execution Model:
  • All-or-nothing execution (no partial fills)
  • Instant settlement
  • Cannot be cancelled (atomic)
  • Requires SOL for transaction fees

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Position Lifecycle

Positions move through three stages:
1

Active

Market is still trading. You can sell your position or monitor P&L.
2

Resolved

Market has settled and outcome is determined. Check if you won or lost.
3

Redeemable

Winning positions can be redeemed for USDC via the Redeem endpoint.

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Security Model

Each API key can only access users it created. Attempting to access another API key’s users returns 403 Forbidden.

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Fee Structure

VenueTrading FeesGas Fees
PolymarketPer Polymarket scheduleGasless (relay covers)
KalshiIncluded in swapUser pays SOL
Kalshi trading requires SOL for Solana transaction fees.

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Comparison to Self-Custody

FeaturePredexonSelf-Custody
Key managementHandled by APIYou manage
Gas feesGasless (Polymarket)You pay
Integration complexityREST API callsWallet SDKs + signing
Multi-chain supportUnified APISeparate integrations
WithdrawalAPI callDirect blockchain tx

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Best Practices

1

Store User IDs

Save the userId from Create User - it’s required for all subsequent operations.
2

Check Balance Before Orders

Always verify sufficient funds with Get Balance before placing orders.
3

Handle Errors Gracefully

Implement retry logic with exponential backoff for transient failures.
4

Monitor Positions

Periodically check positions for resolved markets that can be redeemed.
5

Withdraw Before Deleting

Always withdraw funds before deleting a user - the action is irreversible.

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Next Steps

Create Your First User

Set up a managed wallet

Place an Order

Start trading on prediction markets