GPT-5 Codex is a version of GPT-5 optimized for agentic coding, trained with reinforcement learning on real-world coding tasks across diverse environments. It generates code that closely mirrors human style and pull-request preferences, follows instructions precisely, and iteratively runs tests until it achieves passing results. With a 272k token context window, GPT-5 Codex supports structured output and tool use for integration with development workflows. It is built for developers who need reliable code generation with human-like conventions and testing loops baked into the process. As part of the GPT-5 family's evolution in coding, GPT-5 Codex serves as a foundation for agentic coding workflows, with newer variants such as GPT-5.2 Codex and GPT-5.3 Codex offering stronger performance on large-scale code transformations and complex software engineering.
GPT-5 Codex runs on 1 route through the Opper gateway. Compare residency, ZDR, and training posture at a glance β full data-handling detail per route below.
| Provider | Region | Zero data retention | Training | Input | Output |
|---|---|---|---|---|---|
| OpenAI | US | Enterprise | No | $1.25 | $10.00 |
Training posture across routes: No training on prompts by default.
Each route hosting GPT-5 Codex has its own privacy posture, residency, and GDPR terms. Postures are maintained by Opper with a last-verification timestamp.
Zero data retention is available via Opper Enterprise contract. No training on customer data. US; SCCs; DPA available.
Independent benchmark scores β composite indices for reasoning, coding, and math, plus individual eval scores where available.
Call GPT-5 Codex through the Opper gateway with one API key. Let your coding agent set it up, or call it directly β Opper is drop-in compatible with the OpenAI, Anthropic, and Google AI SDKs.
Copy this and paste it into your coding agent β Claude Code, Cursor, Codex, and more β and it'll wire up Opper for you.
import OpenAI from "openai";const client = new OpenAI({apiKey: process.env.OPPER_API_KEY,baseURL: "https://api.opper.ai/v3/compat",});const completion = await client.chat.completions.create({model: "openai/gpt-5-codex",messages: [{ role: "user", content: "Hello" }],});console.log(completion.choices[0].message.content);
Side-by-side on privacy, EU hosting, pricing, and benchmarks.
