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Secure Relayer Setup

Bayex uses a relayer system to subsidize gas for user onboarding or specific interactions. Security is paramount when handling the relayer’s private keys.

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The Problem

Storing private keys on the client-side (e.g., in .env exposed to the browser) is a critical security vulnerability.

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The Solution: External Relayer Service

We utilize the Polymarket Relayer (relayer-v2) for executing gasless transactions. This removes the need for managing a hot wallet on your own backend for standard operations.

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Architecture

  1. Client Signature: The user signs a typed data structure (EIP-712) in their browser. This signature grants permission for the specific action (e.g., CTWrapper.wrap).
  2. Relayer Submission: The frontend sends this signature and the transaction payload to the Relayer API.
  3. Execution: The Relayer verifies the payload, pays the MATIC gas fees, and submits the transaction to the Polygon network.

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API Endpoint

Production: https://relayer-v2.polymarket.com/

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Implementation Flow

Instead of sending transactions directly via window.ethereum:
  1. Construct the meta-transaction payload.
  2. Request user signature via eth_signTypedData_v4.
  3. POST the payload to the Relayer.
// Example Payload Construction
const payload = {
  to: contractAddress,
  data: encodedFunctionData,
  signature: userSignature,
  // ... other relayer specific fields
};

await axios.post("https://relayer-v2.polymarket.com/transactions", payload);