Native Multimodal api
This api handles native image, audio, and 5-minute video files directly. Use the gpt 5.1 chat api to perform motion tracking and scene description without complex preprocessing.
gpt-5.1-chat-latest / web-search
The gpt 5.1 chat api is OpenAI’s flagship frontier model. It combines high-velocity gpt conversation with deep reasoning. Use this api for multi-step planning, native video ingestion, and complex 5.1 coding tasks across 256k context tokens.
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gpt 5.1 chat api Features
Core technical advantages of the 5.1 gpt chat api.
Agentic Loop Stability
Optimized for autonomous workflows, the gpt 5.1 chat api maintains state consistency over 50+ tool-calling turns, ensuring stable gpt performance for complex agentic operations.
api Codebase Refactoring
Leverage the gpt 5.1 chat api for repository-scale coding. This gpt model understands deep inheritance and cross-file dependencies across massive 200k token source code blocks.
gpt 5.1 reasoning logic
The gpt 5.1 chat api introduces System 2 reasoning, allowing the gpt model to verify steps internally before responding, reducing logical errors in math and physics via the api.
How to Get a gpt-5.1-chat-latest API Key
Getting a gpt-5.1-chat-latest API key takes four steps and a few minutes. Create a free GPTProto account, add credits, generate your key, and make your first call — at $1 / $8 it's a cheaper gpt-5.1-chat-latest API key than going direct, and one key works across every model on the platform. Full gpt-5.1-chat-latest Documentation is in the docs.
Sign up
Create your free GPT Proto account to begin. You can set up an organization for your team at any time.
Top up
Your balance can be used across all models on the platform, including gpt-5.1-chat-latest, giving you the flexibility to experiment and scale as needed.
Generate your API key
In your dashboard, create an API key — you'll need it to authenticate when making requests to gpt-5.1-chat-latest.
Make your first API call
Use your API key with our sample code to send a request to gpt-5.1-chat-latest via GPT Proto and see instant AI-powered results.
gpt 5.1 chat api Common Questions
Find answers regarding gpt performance, api costs, and 5.1 chat capabilities.
How does the gpt 5.1 chat api differ from gpt-4o?
The gpt 5.1 chat api introduces native System 2 reasoning, significantly reducing logical fallacies in complex tasks. While gpt-4o is excellent for fast chat, the 5.1 api excels in multi-step planning and architectural coding. Additionally, the 5.1 gpt version supports a massive 256k context window and native video ingestion, features not fully realized in previous gpt models available through our unified api.
What is the reasoning_effort parameter in this api?
Specific to the gpt 5.1 chat api, reasoning_effort (low, medium, high) controls how much compute the gpt model spends on internal Chain of Thought verification. A higher setting improves accuracy for math and code but increases api latency and cost. This allows developers to tune the gpt performance based on the specific needs of their chat or automation application using our 5.1 endpoints.
Is data sent to the gpt 5.1 chat api used for training?
No. Use of the gpt 5.1 chat api on our platform is governed by strict privacy standards. Neither GPTProto nor OpenAI uses data submitted via this api to train foundation models. This ensures that your proprietary gpt prompts and sensitive business data remain confidential while using the latest 5.1 gpt chat capabilities for your professional projects.
How do I migrate my existing app to the 5.1 api?
Migrating to the gpt 5.1 chat api is straightforward. You simply update your model string to gpt-5.1-chat-latest within your api request. Most parameters remain backward compatible with previous gpt versions, though we recommend testing your chat prompts with the new reasoning_effort setting to find the optimal balance for your 5.1 api implementation and budget.
What are the rate limits for the gpt 5.1 chat api?
The gpt 5.1 chat api starts with a default limit of 5,000 RPM and 2M TPM. For enterprise scale, we can scale your gpt access up to 50M TPM. Our api also includes a unique Queue header to automatically handle 429 errors, ensuring your gpt chat applications maintain high availability even during peak usage of the 5.1 model reasoning engines.
Can I use structured JSON with the gpt 5.1 chat api?
Yes, the gpt 5.1 chat api features an enhanced JSON mode. By setting the response_format to json_object, the gpt model guarantees that outputs strictly follow your provided schema. This api capability is essential for developers building automated gpt workflows that require reliable data parsing from complex chat interactions or deep document analysis using 5.1 logic.