Frontier Coding Proficiency
Achieves 92.4% on HumanEval for expert-level refactoring and logic error identification in complex codebases.
Claude Sonnet 4.5 (Build 20250929)
ai claude sonnet 4.5 balances elite intelligence with speed. This ai model excels at multi-step reasoning, frontier coding, and visual analysis. Ideal for ai agents, it offers 200k context and 99.8% RAG accuracy via the GPTProto.com API.
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": "claude-sonnet-4-5-20250929",
"messages": [
{
"role": "user",
"content": "Hello"
}
]
}'Claude Sonnet 4.5 20250929 pricing
Estimate a request with real work scenarios. GPTProto token pricing is 10% below official rates.
UsageQuantityRateCost
tokens
$2.7/1M$0.004tokens
$13.5/1M$0.0108tokens
$3.375/1M$0.0101tokens
$0.27/1M$0.0067Cost per request$0.0317
Requests
Top-up amount
Top-up $100 and you get:
1. Top-up credits with permanent validity. You will receive a total of $100.00.
2. Additional 10% model discount, saving $11.108 versus direct official Claude API calls.
Related Models
All Models| Model | Input → Output | ||||
|---|---|---|---|---|---|
 | 1M | $2.70 / $13.50 per 1M | $3.38 / $0.27 per 1M | Input: TextInput: Document Output: Text | |
| — | — | $0.15 / $0.50 per 1M | — / $0.03 per 1M | Input: TextInput: ImageInput: VideoInput: Document Output: Text | |
| — | — | $0.44 / $1.32 per 1M | — / $0.01 per 1M | Input: TextInput: Image Output: Text | |
| 1.05M | $1.26 / $3.96 per 1M | — / $0.23 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $0.45 / $2.25 per 1M | — / $0.04 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 500K | $1.20 / $3.60 per 1M | — / $0.30 per 1M | Input: TextInput: Image Output: Text | ||
| 1M | $1.80 / $5.40 per 1M | $2.25 / $0.23 per 1M | Input: TextInput: ImageInput: VideoInput: Document Output: Text | ||
| 1M | $4.50 / $22.50 per 1M | $5.63 / $0.45 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $0.45 / $2.25 per 1M | — / $0.04 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $0.18 / $1.50 per 1M | $0.02 / $0.02 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $2.70 / $13.50 per 1M | $0.27 / $0.27 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $0.16 / $0.96 per 1M | $0.20 / $0.02 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $1.60 / $9.60 per 1M | $2.00 / $0.16 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $4.00 / $24.00 per 1M | $5.00 / $0.40 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 500K | $1.20 / $3.60 per 1M | $0.30 / $0.30 per 1M | Input: TextInput: Image Output: Text | ||
| 1M | $1.80 / $9.00 per 1M | $2.25 / $0.18 per 1M | Input: TextInput: Document Output: Text | ||
| 1.05M | $0.48 / $0.96 per 1M | $0.10 / $0.10 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $1.26 / $3.96 per 1M | $0.23 / $0.23 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1M | $9.00 / $45.00 per 1M | $11.25 / $0.90 per 1M | Input: TextInput: Document Output: Text | ||
| 1M | $0.36 / $1.44 per 1M | $0.07 / $0.07 per 1M | Input: TextInput: Document Output: Text | ||
| 1M | $4.50 / $22.50 per 1M | $5.63 / $0.45 per 1M | Input: TextInput: Document Output: Text | ||
| 1M | $4.50 / $22.50 per 1M | $5.63 / $0.45 per 1M | Input: TextInput: Document Output: Text | ||
| — | 1.05M | $0.44 / $1.32 per 1M | — / $0.01 per 1M | Input: Text Output: Text | |
| — | 1.05M | $1.32 / $3.96 per 1M | — / $0.04 per 1M | Input: Text Output: Text | |
| 1M | $0.75 / $1.50 per 1M | $0.12 / $0.12 per 1M | Input: TextInput: Image Output: Text | ||
| 262K | $0.85 / $3.60 per 1M | $0.14 / $0.14 per 1M | Input: TextInput: Document Output: Text | ||
| 1M | $4.50 / $22.50 per 1M | $5.63 / $0.45 per 1M | Input: TextInput: Document Output: Text | ||
| 205K | $0.24 / $0.96 per 1M | $0.30 / $0.02 per 1M | Input: TextInput: Document Output: Text | ||
| 262K | $0.54 / $2.70 per 1M | $0.09 / $0.09 per 1M | Input: TextInput: Document Output: Text | ||
| — | $0.04 / $0.18 per 1M | $0.009 / $0.009 per 1M | Input: Text Output: Text | ||
| 262K | $0.10 / $0.97 per 1M | — | Input: TextInput: Image Output: Text | ||
| 262K | $0.10 / $0.97 per 1M | — | Input: TextInput: Image Output: Text | ||
| 262K | $0.02 / $0.18 per 1M | — | Input: TextInput: Image Output: Text |
Key Features of ai claude sonnet 4.5
Explore the technical advancements that make this ai model a leader in coding, tool use, and long-context analysis for complex ai applications.
Sub-Second Tool Invocation
Optimized for agentic workflows with a sub-1% failure rate in tool-calling syntax for reliable execution.
Massive 200k Context Window
High-fidelity recall across 200,000 tokens with 99.8% accuracy in complex RAG data extraction tasks.
Visual Reasoning & OCR
Interprets architectural blueprints and financial charts to extract structured data with high accuracy.
Common Questions About ai claude sonnet 4.5
Find answers regarding the capabilities, pricing, and integration of this ai model. Learn how ai claude sonnet 4.5 compares to other frontier models.
How does ai claude sonnet 4.5 handle coding tasks?
This ai model achieves a 92.4% HumanEval score, outperforming many flagship systems. It specializes in refactoring multi-file codebases and debugging asynchronous logic. Developers can use this ai to build autonomous agents that browse repositories, run tests, and fix bugs with minimal human supervision.
What is the context window for this ai model?
The ai claude sonnet 4.5 features a massive 200,000-token context window. It maintains a 99.8% accuracy rate in needle-in-a-haystack benchmarks, even when the critical information is located in the middle of a massive dataset. This makes the ai perfect for analyzing long legal contracts or medical records without losing threads.
Can this ai process images and visual data?
Yes, it is a native multimodal ai. It interprets complex financial charts, architectural blueprints, and UI mockups with high OCR precision. You can extract structured JSON data from unstructured visual inputs efficiently using this ai, making it ideal for automated data entry and visual reasoning workflows.
How does ai prompt caching reduce costs?
Prompt caching allows this ai to reuse context blocks, cutting latency by up to 80%. For repetitive tasks or long system prompts, it reduces costs by up to 90%. It is an essential feature for ai applications requiring frequent references to stable technical documentation or massive knowledge bases.
Is my data used to train the ai foundation?
No. Data passed through our API to ai claude sonnet 4.5 is never used for training foundation models. We maintain strict privacy agreements with Anthropic to ensure your ai workflows remain secure, and we comply with Zero Data Retention standards for eligible enterprise features.
What is the cost of using this ai API?
The ai claude sonnet 4.5 costs $3.00 per 1M input tokens and $15.00 per 1M output tokens. This makes it roughly 1/5th the price of the Opus tier while providing nearly 95% of the same reasoning performance for standard coding, extraction, and pedagogical tasks.
Related Articles
Guides, comparisons, and updates related to this model.
All Articles
Claude Sonnet 4.5: A Leap in AI Reasoning
Explore how Claude Sonnet 4.5 outperforms competitors in coding, context, and academic honesty. Optimize your workflow today. Discover more.
Claude 3.5 Sonnet API: The New Developer Standard
Discover how the Claude 3.5 Sonnet API is outperforming rivals in speed and reasoning. Learn how to integrate it into your workflow. Get started now.
Claude Haiku 4.5 vs Sonnet 4.5: Real Cost & ROI
Choosing between claude haiku 4.5 vs sonnet 4.5 comes down to speed versus deep logic. Learn how a hybrid routing approach saves money. Read the guide.
Claude Sonnet 4: Reshaping Digital Work
Discover how Claude Sonnet 4 is transforming productivity and creativity for millions of users. Learn about its key features and real-world applications.