GPT 5.1 Codex Max
GPT 5.1 Codex Max applies maximum compute to the GPT-5.1 codex architecture, delivering the deepest reasoning and most thorough code analysis available in OpenAI's coding agent lineup for the most demanding software engineering tasks.
import { streamText } from 'ai'
const result = streamText({ model: 'openai/gpt-5.1-codex-max', prompt: 'Why is the sky blue?'})What To Consider When Choosing a Provider
Zero Data Retention
AI Gateway supports Zero Data Retention for this model via direct gateway requests (BYOK is not included). To configure this, check the documentation.Authentication
AI Gateway authenticates requests using an API key or OIDC token. You do not need to manage provider credentials directly.
GPT 5.1 Codex Max is designed for tasks where standard codex models fall short. It applies additional computation to produce more thorough analysis and higher-quality code on genuinely difficult problems.
Most teams use codex max for their hardest tasks (security audits, architectural redesigns, complex migrations) while routing routine work to standard codex or codex mini.
When to Use GPT 5.1 Codex Max
Best For
Critical security audits:
Thorough analysis of codebases for vulnerabilities with maximum reasoning depth
Large-scale architectural redesigns:
Changes that require understanding and restructuring entire systems
Complex migration projects:
Converting between frameworks or architectures with many interdependencies
Hard debugging:
Tracing subtle, cross-cutting bugs that require extensive codebase analysis
Quality-critical code review:
Final review of changes where missed issues have high consequences
Consider Alternatives When
Standard coding tasks:
GPT-5.1 codex handles most tasks well at lower cost
Simple bug fixes:
Codex mini is faster and more affordable for routine fixes
Non-coding analysis:
GPT-5.1 thinking for general reasoning tasks
Speed-sensitive workflows:
Any smaller codex variant when response time matters more than depth
Conclusion
GPT 5.1 Codex Max applies maximum compute within the GPT-5.1 codex family to the hardest software engineering challenges. For security audits, architectural redesigns, and other tasks where code quality is paramount, it is the premium tier of the GPT-5.1 codex lineup.
FAQ
It applies more compute per request, enabling deeper reasoning and more thorough analysis. The improvement is most significant on hard problems; simple tasks may not benefit noticeably.
For security audits, large architectural changes, complex migrations, and any task where the consequences of missed issues are high. For routine coding, standard codex is more cost-effective.
400K tokens, matching the GPT-5.1 codex family.
AI Gateway accepts a single API key or OIDC token for all requests. You don't embed OpenAI credentials in your application; AI Gateway routes and authenticates on your behalf.
Yes. Like other codex variants, it operates in sandboxed environments where it runs tests and validates output before returning results.
This page shows live throughput and time-to-first-token metrics measured across real AI Gateway traffic. Codex max may take longer due to additional compute applied per request.
