Docs

OpenAI-Compatible GPT and Codex API Docs

Last updated: July 6, 2026

Start from the API key, base URL, and setup files delivered after payment.

Use this reference to authenticate server-side requests, call GPT-5.5 and Codex 5.5, 5.4, 5.3-style endpoints, understand unlimited token consumption with 4 concurrent connections, and prepare billing or key lifecycle webhook receiver workflows.

const response = await fetch("https://unlimitedcodex.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.UCX_API_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    model: "gpt-5.5",
    messages: [{ role: "user", content: "Write a release note for our AI feature." }]
  })
});