Create a Market

Creates a new prediction market on PredictBase. A market creation fee of 1 USDC is automatically deducted from the creator’s PredictBase balance when the transaction is submitted.

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Endpoint

POST /create-market-for-user

Full URL

https://api.predictbase.app/create-market-for-user

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Authentication

This endpoint requires authentication. You must include your API key in the request headers:

x-api-key: YOUR_API_KEY

The API key must be authorized for the creator address.

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Request Body

{
  "creator": "0xCreatorAddress",
  "question": "Will BTC be above $100k by 2026?",
  "optionTitles": ["Yes", "No"],
  "optionImages": ["", ""],
  "categories": ["Crypto", "BTC"],
  "details": "Longer description / rules",
  "image": "https://.../market-hero.png",
  "endDate": "1735689600",
}

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Field Notes

• creator Wallet address that will own and manage the market

• endDate Unix timestamp in seconds (uint64, string or number)

• optionTitles Titles for each market option (e.g. ["Yes", "No"])

• optionImages (Optional) Image URLs for each option. This field is not implemented yet and is currently ignored if provided.

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Response (Success)

{
  "success": true,
  "txHash": "0x...",
  "receipt": {
    "...": "EVM transaction receipt fields"
  }
}

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Pending Receipt

{
  "success": true,
  "txHash": "0x...",
  "receipt": null,
  "warning": "Tx sent but receipt not yet available"
}

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⚠️ Failure Cases

• Missing or invalid x-api-key

• API key not authorized for the creator

• Insufficient balance to cover the 1 USDC market creation fee

• Invalid market parameters

• On-chain transaction failure