Synapse API — X Layer Gas Estimator

Choose this endpoint when you need to estimate gas costs specifically on the X Layer (OKX Layer 2) network before committing to a transaction. It is ideal for pre-flight checks, budgeting, and avoiding failed transactions due to insufficient gas. Use it over generic gas oracles when you need simulation-based estimates for a specific sender, recipient, and calldata combination on X Layer.

• Invalid or malformed Ethereum address in 'to' or 'from' fields returns an error
• Invalid hex-encoded 'data' field causes parsing failure
• Transaction simulation fails if the contract logic reverts, returning a revert error
• Missing required fields may return a 400 bad request
• Network unavailability or RPC issues may cause a timeout or 503 error