GPT-5 Codex API

Language model · model id gpt-5-codex

GPT-5 Codex is available through G0I — call it with a standard OpenAI-compatible request, the same way you call every other model on the platform.

How to call GPT-5 Codex

G0I is OpenAI-compatible. Point your client at https://g0i.ai/v1, set the model field to gpt-5-codex, and send a chat completion via /v1/chat/completions:

curl https://g0i.ai/v1/chat/completions \
  -H "Authorization: Bearer $G0I_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-5-codex","messages":[{"role":"user","content":"Hello"}]}'

Why use GPT-5 Codex through G0I

One API key — GPT-5 Codex plus 470+ other models, no separate provider account.
OpenAI-compatible — works with the OpenAI SDK and any compatible tooling.
Switch freely — change the model field to compare GPT-5 Codex against other models with zero code changes.
Start free — create an account and test with a free token quota.

Get an API key — use GPT-5 Codex now →

Browse the full model catalog, read the quickstart, or see pricing. Looking for an OpenAI API alternative or a unified AI API? G0I covers it.