OpenAI-compatible chat completions for gpt-6.1-sol (OpenAI's newest model) and 25 more OpenAI models (gpt-6, gpt-5.x, gpt-4.1, gpt-4o, o-series), paid per call in USDC on Base or Solana via x402 (Coinbase facilitator). No account or API key. One endpoint per model plus one generic endpoint; Flex, Standard and Fast tiers; reasoning levels via model suffix; answers with no visible output are not charged. Live prices: https://openai.mm.family/x402/pricing