# GPT55 Model Gateway

GPT55 is an OpenAI-compatible x402 Base USDC gateway. GPT-5.6 Luna Standard is the default upstream gpt-5.6-luna path at the historically converting $0.00293 public entry quote. Buyers choose prepaid Luna call packs or per-request x402 calls. GPT-5.6 Soul and Terra remain available. Model routes support gpt-5.6-sol, gpt-5.6-luna, gpt-5.6-terra, gpt-5.6, gpt-5.5, gpt-5.3-codex, gpt-5.4.

x402 guide: https://gpt55.558686.xyz/x402/guides/ai-agent-x402-api

Primary Standard offer:
- Model: GPT-5.6 Luna Standard one-request result
- POST https://gpt55.558686.xyz/v1/chat/completions/standard
- Price: $0.00293 (2930 atomic)
- Network/asset: eip155:8453 / Base USDC
- payTo: 0x1f0130669ca6fd02e025a984cc038f139df19a2f
- Browser: https://gpt55.558686.xyz/x402/service?checkout=standard-chat
- Agent: https://gpt55.558686.xyz/x402/first-payment-client.mjs

Payment routing:
- Facilitator routing: provider-pool
- Active facilitators: https://facilitator.xpay.sh

Machine assets:
- Service hub: https://gpt55.558686.xyz/x402/service
- Service hub JSON: https://gpt55.558686.xyz/x402/service.json
- Compatibility index: https://gpt55.558686.xyz/x402/compatibility.json
- Project index: https://gpt55.558686.xyz/projects/
- Project 558686 page: https://gpt55.558686.xyz/projects/558686/
- Actual tool catalog: https://gpt55.558686.xyz/tools.json
- APIs catalog: https://gpt55.558686.xyz/apis.json
- AI catalog: https://gpt55.558686.xyz/.well-known/ai-catalog.json
- MCP server card: https://gpt55.558686.xyz/.well-known/mcp/server-card.json
- MCP first-purchase guide: https://gpt55.558686.xyz/x402/mcp-first-purchase-kit
- x402 discovery: https://gpt55.558686.xyz/.well-known/x402
- OpenAPI: https://gpt55.558686.xyz/openapi.json
- pricing.json: https://gpt55.558686.xyz/pricing.json
- server.json: https://gpt55.558686.xyz/server.json
- Split-host lifecycle: https://gpt55.558686.xyz/projects/split.json

Featured GPT55 routes:
- POST https://gpt55.558686.xyz/v1/chat/completions/standard: GPT-5.6 Luna Standard chat completion ($0.00293)
- POST https://gpt55.558686.xyz/v1/chat/completions/gpt-5.6-sol: GPT-5.6 Soul chat completion ($0.099995)
- POST https://gpt55.558686.xyz/v1/chat/completions/gpt-5.6-luna: GPT-5.6 Luna chat completion ($0.019999)
- POST https://gpt55.558686.xyz/v1/chat/completions/gpt-5.6-terra: GPT-5.6 Terra chat completion ($0.049998)
- POST https://gpt55.558686.xyz/v1/chat/completions/gpt-5.6: GPT-5.6 Soul chat completion alias ($0.099995)
- POST https://gpt55.558686.xyz/v1/chat/completions/gpt-5.5: gpt-5.5 ($0.019999)
- POST https://gpt55.558686.xyz/v1/chat/completions/gpt-5.3-codex: gpt-5.3-codex ($0.007472)
- GET https://gpt55.558686.xyz/v1/paid/call-packs/gpt-5.6-sol-100: gpt 5.6 sol 100 (prepaid call pack live quote)
- GET https://gpt55.558686.xyz/v1/paid/call-packs/gpt-5.6-luna-100: gpt 5.6 luna 100 (prepaid call pack live quote)
- GET https://gpt55.558686.xyz/v1/paid/call-packs/gpt-5.6-terra-100: gpt 5.6 terra 100 (prepaid call pack live quote)
- POST https://gpt55.558686.xyz/v1/x402-ping: x402 ping (live x402 quote)

Retired split-host policy:
- Historical split hosts are retired and consolidated. Use only the canonical GPT55 service hub for purchases and fresh quotes.