# NexRelay API Reference

NexRelay is a prepaid AI API gateway for developers who need OpenAI-compatible, Claude-compatible, and Gemini-style API access with request-level logs, per-key budgets, wallet balance protection, model policy, and output caps.

Base URL for OpenAI-compatible clients:
https://nexrelay-api.xyz/api/v1

Supported public model identifiers:
- gpt-5.2
- gpt-5.3
- gpt-5.4
- gpt-5.5

Authentication:
- Authorization: Bearer YOUR_NEXRELAY_API_KEY
- x-api-key: YOUR_NEXRELAY_API_KEY

Endpoints:
- POST https://nexrelay-api.xyz/api/v1/chat/completions
  Send OpenAI-compatible chat requests through a prepaid NexRelay API key.
- POST https://nexrelay-api.xyz/api/v1/responses
  Send OpenAI-compatible Responses API requests with wallet and key controls.
- GET https://nexrelay-api.xyz/api/v1/models
  List public model identifiers supported by the compatible gateway.
- POST https://nexrelay-api.xyz/v1/messages
  Send Claude-style message requests from compatible clients.
- POST https://nexrelay-api.xyz/api/v1/messages
  Use the Claude-style messages route under the API namespace.
- GET https://nexrelay-api.xyz/v1beta/models
  List Gemini-style model metadata for compatible clients.
- POST https://nexrelay-api.xyz/v1beta/models/{model}:generateContent
  Send Gemini-style generation requests through compatible routing.

OpenAI-compatible chat example:

curl https://nexrelay-api.xyz/api/v1/chat/completions \
  -H "Authorization: Bearer YOUR_NEXRELAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-5.4","messages":[{"role":"user","content":"Say hello in one sentence."}],"max_tokens":120}'

Responses API example:

curl https://nexrelay-api.xyz/api/v1/responses \
  -H "Authorization: Bearer YOUR_NEXRELAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-5.5","input":"Explain prepaid API cost control.","max_output_tokens":200}'

Claude-compatible example:

curl https://nexrelay-api.xyz/v1/messages \
  -H "Authorization: Bearer YOUR_NEXRELAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"claude-sonnet-4-6","max_tokens":200,"messages":[{"role":"user","content":"Explain request-level API logs."}]}'

Machine-readable assets:
- OpenAPI: https://nexrelay-api.xyz/openapi.json
- Postman collection: https://nexrelay-api.xyz/postman-collection.json
- AI plugin discovery: https://nexrelay-api.xyz/.well-known/ai-plugin.json
- LLM summary: https://nexrelay-api.xyz/llms.txt
- Full LLM index: https://nexrelay-api.xyz/llms-full.txt