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GPT 5.1 Codex Max
GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic...
- Input
- text
- image
- Output
- text
Providers
Available through 1 free provider. Use the model ID and API settings below to connect.
Vercel AI Gateway
VAVercel AI Gateway
* The provider match may differ from this model. Check its docs for details.
Benchmarks
Compare scores and explore results by category.
No benchmark results are available for this model yet.
Frequently asked questions
Free access, setup, and what to expect.
Free API access for GPT 5.1 Codex Max is listed through Vercel AI Gateway, but a specific request or token allowance isn’t available in the listed data. Check the GPT 5.1 Codex Max provider pricing and rate limits for what’s included and any account requirements.
To use GPT 5.1 Codex Max, choose one of the listed GPT 5.1 Codex Max API providers and follow the provider’s account and API-key setup guide. Copy the GPT 5.1 Codex Max model ID and connection settings for your chosen provider into your app or API client. Model IDs can differ between providers. API requests go directly to the provider; Free Models is a comparison site.
GPT 5.1 Codex Max accepts text and image as listed input formats. Listed output formats include text. Image or audio input support does not imply image or audio generation. Check the chosen provider’s GPT 5.1 Codex Max documentation for supported file types and request formats.
GPT 5.1 Codex Max has a listed context window of 400K tokens. Tokens are small pieces of content rather than a word count. Instructions, conversation history, and other inputs use context space, and the response also needs room. The maximum output length for GPT 5.1 Codex Max may be smaller than the context window and can vary by provider.
GPT 5.1 Codex Max has both reasoning and tool calling listed as supported capabilities. Reasoning enables additional processing for complex problems. Tool calling allows a model to request functions that your app executes. Check the chosen provider’s documentation for capability availability and setup.
No benchmark results are listed for GPT 5.1 Codex Max yet. Missing scores don’t establish poor performance. Compare scores within the same benchmark: coding indexes, Elo ratings, and win rates measure different things. The index comparison charts include only scored free models listed on Free Models. Evaluate GPT 5.1 Codex Max on examples from your own task alongside context size and provider limits.