{"name":"gas-price","description":"Gas price API / EIP-1559 fee estimator / Base + Ethereum + Optimism + Arbitrum gas tracker / pre-tx cost estimator. Reads the chain's latest block, derives base fee, suggests priority fees for safe-low/standard/fast tiers, computes total maxFeePerGas, and converts cost to USD for common tx types.","price":"$0.02","method":"POST","input_schema":{"properties":{"chain":{"type":"string","enum":["base","ethereum","optimism","arbitrum","polygon"],"description":"EVM L1/L2 to read gas from. Default 'base'."}}},"input_example":{"chain":"base"},"output_example":{"chain":"base","base_fee_gwei":0.005,"priority_fee_gwei":{"safe_low":0.001,"standard":0.001,"fast":0.002},"total_recommended_gwei":0.006,"block_number":27500000,"eth_price_usd":3500,"cost_usd":{"transfer":0.0008,"erc20_transfer":0.0012,"uniswap_swap":0.004,"nft_mint":0.006},"timestamp":"2026-05-06T22:00:00Z"},"x402_payment_required":true,"x402_facilitator":"https://api.cdp.coinbase.com/platform/v2/x402"}