OpenAI
GPT 5.1 Chat Latest
Chat
The gpt 5.1 chat latest api is OpenAI’s flagship frontier model. It merges high-velocity conversational chat with deep systemic reasoning, excelling at architectural coding and complex planning within a massive 256k context window.

Modalities

Input: TextInput: ImageInput: Document
Output: Text

API Usage Examples
curl --request POST "https://gptproto.com/v1/chat/completions" \
  --header "Authorization: Bearer $GPTPROTO_API_KEY" \
  --header "Content-Type: application/json" \
  --data '{
    "model": "gpt-5.1-chat-latest",
    "messages": [
      {
        "role": "user",
        "content": "Hello"
      }
    ]
  }'
GPT 5.1 Chat Latest pricing

Estimate a request with real work scenarios. GPTProto token pricing is 20% below official rates.

Cost calculator

Multi-turn agent with cached context.
$1 / 1M$0.0015
$8 / 1M$0.0064
$0.1 / 1M$0.0003
$0.1 / 1M$0.0025
Cost per request$0.0107

Top up

GPTProto vs official pricing.
Requests
You pay
20% off
$100
You receive$100.00

Save$24.99 (20%)vs OpenAI

gpt 5.1 chat latest api Key Features

Core technical advantages of the gpt 5.1 chat latest api for developers and researchers.

gpt 5.1 System 2 Reasoning

This gpt iteration performs native chain-of-thought verification, reducing logic fallacies by 40% compared to previous chat models for math tasks.

Agentic Loop Stability

The gpt 5.1 chat latest api maintains state consistency over 50+ tool-calling turns, achieving a 94% success rate on long-horizon navigation tests.

Native Video Ingestion

Directly pass video files into the gpt chat completion endpoint for temporal analysis and motion tracking without pre-processing frames.

Codebase-Scale Refactoring

Optimized for the latest api to understand deep inheritance and dependencies in large repositories with a 256k context window.

Related Models
All Models
ModelInput → Output
GPT 5.1 Chat LatestCurrent
—$1.00 / $8.00 per 1M$0.10 / $0.10 per 1M
Input: TextInput: ImageInput: Document
Output: Text
Grok 4.6
500K$1.20 / $3.60 per 1M— / $0.30 per 1M
Input: TextInput: Image
Output: Text
Qwen3.8 Max
1M$1.80 / $5.40 per 1M$2.25 / $0.23 per 1M
Input: TextInput: ImageInput: VideoInput: Document
Output: Text
Claude Opus 5
1M$4.00 / $20.00 per 1M$5.00 / $0.40 per 1M
Input: TextInput: ImageInput: Document
Output: Text
Gemini 3.6 Flash
1.05M$0.90 / $4.50 per 1M$0.09 / $0.09 per 1M
Input: TextInput: ImageInput: Document
Output: Text
Gemini 3.5 Flash Lite
1.05M$0.18 / $1.50 per 1M$0.02 / $0.02 per 1M
Input: TextInput: ImageInput: Document
Output: Text
Kimi K3
1.05M$2.70 / $13.50 per 1M$0.27 / $0.27 per 1M
Input: TextInput: ImageInput: Document
Output: Text
GPT 5.6 Luna
1.05M$0.16 / $0.96 per 1M$0.20 / $0.02 per 1M
Input: TextInput: ImageInput: Document
Output: Text
GPT 5.6 Terra
1.05M$1.60 / $9.60 per 1M$2.00 / $0.16 per 1M
Input: TextInput: ImageInput: Document
Output: Text
GPT 5.6 Sol
1.05M$4.00 / $24.00 per 1M$5.00 / $0.40 per 1M
Input: TextInput: ImageInput: Document
Output: Text
Grok 4.5
500K$1.20 / $3.60 per 1M$0.30 / $0.30 per 1M
Input: TextInput: Image
Output: Text
Claude Sonnet 5
1M$1.60 / $8.00 per 1M$2.00 / $0.16 per 1M
Input: TextInput: Document
Output: Text
Minimax M3
1.05M$0.48 / $0.96 per 1M$0.10 / $0.10 per 1M
Input: TextInput: ImageInput: Document
Output: Text
GLM 5.2
1.05M$1.26 / $3.96 per 1M$0.23 / $0.23 per 1M
Input: TextInput: ImageInput: Document
Output: Text
Claude Fable 5
1M$8.00 / $40.00 per 1M$10.00 / $0.80 per 1M
Input: TextInput: Document
Output: Text
Qwen3.7 Max
1M$0.36 / $1.44 per 1M$0.07 / $0.07 per 1M
Input: TextInput: Document
Output: Text
Gemini 3.5 Flash
1.05M$0.90 / $5.40 per 1M$0.09 / $0.09 per 1M
Input: TextInput: ImageInput: Document
Output: Text
DeepSeek v4 Flash
—1.05M$0.14 / $0.28 per 1M— / $0.0028 per 1M
Input: Text
Output: Text
DeepSeek v4 Pro
1.05M$1.04 / $2.09 per 1M$0.0087 / $0.0087 per 1M
Input: Text
Output: Text
Grok 4.3
1M$0.75 / $1.50 per 1M$0.12 / $0.12 per 1M
Input: TextInput: Image
Output: Text
GPT 5.4 Pro
1.05M$24.00 / $144.00 per 1M—
Input: TextInput: ImageInput: Document
Output: Text
GPT 5.5 Pro
1.05M$24.00 / $144.00 per 1M—
Input: TextInput: ImageInput: Document
Output: Text
GPT 5.5
1.05M$4.00 / $24.00 per 1M$0.40 / $0.40 per 1M
Input: TextInput: ImageInput: Document
Output: Text
Kimi K2.6
262K$0.85 / $3.60 per 1M$0.14 / $0.14 per 1M
Input: TextInput: Document
Output: Text
GLM 5.1
205K$1.26 / $3.96 per 1M$0.23 / $0.23 per 1M
Input: TextInput: Document
Output: Text
GLM 5 Turbo
203K$1.08 / $3.60 per 1M$0.22 / $0.22 per 1M
Input: TextInput: Document
Output: Text
DeepSeek v3.2
164K$0.17 / $0.25 per 1M$0.02 / $0.02 per 1M
Input: Text
Output: Text
Minimax M2.5
205K$0.24 / $0.96 per 1M$0.30 / $0.02 per 1M
Input: TextInput: Document
Output: Text
Kimi K2.5
262K$0.54 / $2.70 per 1M$0.09 / $0.09 per 1M
Input: TextInput: Document
Output: Text
Qwen Turbo
—$0.04 / $0.18 per 1M$0.009 / $0.009 per 1M
Input: Text
Output: Text
Doubao Seed 1.6 Thinking 250715
262K$0.10 / $0.97 per 1M—
Input: TextInput: Image
Output: Text
Doubao Seed 1.6 Thinking 250615
262K$0.10 / $0.97 per 1M—
Input: TextInput: Image
Output: Text
Doubao Seed 1.6 Flash 250615
262K$0.02 / $0.18 per 1M—
Input: TextInput: Image
Output: Text

gpt 5.1 chat latest api FAQ

Common questions about the gpt 5.1 chat latest api, covering migration, technical reasoning, and developer billing on GPTProto.

How does gpt 5.1 differ from the standard chat api?

The gpt 5.1 chat latest api includes Integrated System 2 Reasoning, which allows the gpt model to verify its logic before outputting text. Unlike standard chat versions, this 5.1 release is optimized for agentic loop stability and native video ingestion. Through the GPTProto api, you also benefit from unified credit billing and higher initial rate limits than standard OpenAI tiers, making it easier to scale gpt 5.1 applications.

Is my gpt 5.1 chat api data used for training?

No. When using the gpt 5.1 chat latest api through our platform, your data is protected. Both GPTProto and the underlying OpenAI API terms for the 5.1 model strictly prohibit the use of customer inputs or outputs for training foundation models. This ensures that your proprietary code, legal documents, and chat interactions remain confidential while leveraging the latest api capabilities.

What is the reasoning_effort parameter in gpt 5.1?

Reasoning_effort is a new parameter for the gpt 5.1 chat latest api that controls the depth of the model's internal Chain of Thought. Setting this to 'high' via the api tells the gpt model to spend more compute on verification, which is ideal for complex math or architectural coding. While it increases latency slightly, it significantly improves accuracy for the 5.1 chat model compared to low-effort reasoning settings.

How do I migrate my app to the gpt 5.1 chat latest api?

Migration to gpt 5.1 is straightforward. Simply update your model string to 'gpt-5.1-chat-latest' in your api requests. Most parameters from previous gpt chat versions are backward compatible. However, we recommend testing your prompts with the new reasoning_effort parameter to fully utilize the 5.1 engine's logical depth. GPTProto handles the routing to ensure you're always hitting the latest api version available.

Does the gpt 5.1 api support fine-tuning?

Currently, fine-tuning for the gpt 5.1 chat latest api is in a private beta phase. It is primarily available to Enterprise tier customers who require specialized domain adaptation for the 5.1 model. For most high-level reasoning and coding tasks, the base gpt 5.1 chat model provides sufficient zero-shot performance, but you can contact GPTProto support to inquire about beta access for the latest api fine-tuning features.

Can I get enterprise invoicing for gpt 5.1 usage?

Yes, GPTProto provides consolidated monthly invoicing for all gpt 5.1 chat latest api usage. This allows your team to manage costs across multiple gpt models and api keys through a single financial statement. Our platform also offers volume discounts and context caching for the 5.1 chat model, reducing the input price by 50% for repeated data, which is essential for high-volume latest api implementations.