x402 GPT API | GPT-5.6 Luna Base USDC

Get one OpenAI-compatible GPT-5.6 Luna Standard result for $0.00293 USDC on Base.

This is an x402 GPT API with USDC on Base, not an OpenAI-operated product. The endpoint provides one live quote, one POST request, and one response.

The Standard quote is 2930 atomic USDC units on Base eip155:8453; re-read the live 402 response immediately before payment.

POST https://gpt55.558686.xyz/v1/chat/completions/standard

Use the browser wallet checkout with an injected Base wallet, or the quote-first agent fallback when no wallet UI is available. Read the x402 GPT API integration guide for the complete flow.

For the focused buyer problem, read the static x402 GPT API guide with a runnable quote, payment retry contract, and factual FAQ.

The EVM Wallet Balance Snapshot remains available as a separate utility alternative at $0.001 USDC.

Lowest-cost model first payment: translate canary

Validate a buyer-owned x402 wallet or client with one short translation before buying a larger model call. The live quote is $0.00293 USDC on Base.

POST https://gpt55.558686.xyz/v1/tools/translate

ROUTE_ID=translate-canary MAX_USDC=0.00293 node first-payment-client.mjs

Quote-only is the default. Payment is an explicit buyer-owned runtime opt-in after verifying amount, network, asset, and payTo.

• Service hub
• Buy GPT-5.6 Luna Standard
• Wallet Balance alternative
• Key Pack upgrade
• Machine catalog
• Integration guide
• Buyer execution contract
• Source repository

Never send private keys, seed phrases, API keys, or payment headers to the service or place them in GitHub issues.