Jun 23, 2025

Claude

Claude stands out as one of the most sophisticated and versatile large language model families available today. Developed by Anthropic, Claude represents a new generation of AI that combines exceptional reasoning capabilities with a strong focus on safety and helpfulness.

This guide will walk you through everything you need to know about Claude's model family, from the lightning-fast Haiku to the powerhouse Opus 4.

The Claude model family

Claude's model family follows a thoughtful architecture that balances performance, speed, and cost across different use cases. The naming convention draws inspiration from poetry forms, with each model designed to excel in specific scenarios while maintaining consistent quality and safety standards.

At the foundation of the family sits Claude 3.5 Haiku, designed for applications requiring rapid responses and high throughput. This model excels in scenarios where speed matters more than deep reasoning, like real-time customer support, content moderation, or high-volume data processing tasks.

Moving up the intelligence ladder, Claude Sonnet 4 represents the sweet spot for most developers. It delivers sophisticated reasoning and coding capabilities while maintaining excellent performance characteristics. This model is a good choice for complex chatbots, code generation, and advanced data analysis tasks.

For the most demanding applications, Claude Opus 4 stands as Anthropic's flagship model. This powerhouse tackles the most complex reasoning challenges, excels at multi-step coding projects, and delivers state-of-the-art performance on tasks that require focus and problem-solving.

The family also includes Claude Sonnet 3.7, which introduced the groundbreaking "extended thinking" capability, allowing the model to show its step-by-step reasoning process. While newer models have surpassed it in raw performance, Sonnet 3.7 remains valuable for understanding how Claude approaches complex problems.

Extended thinking

One of Claude's most innovative features is extended thinking, available in Claude Opus 4, Sonnet 4, and Sonnet 3.7.

Traditional language models generate responses in a single forward pass, essentially "thinking out loud" as they write. Extended thinking allows Claude to engage in internal reasoning before crafting its final response, similar to how humans might work through a problem step-by-step before presenting their solution.

When extended thinking is enabled, Claude creates internal reasoning blocks where it analyzes the problem, considers different approaches, and works through complex logic. This process is particularly valuable for tasks requiring mathematical reasoning, complex coding challenges, or multi-step analysis.

The feature comes with configurable token budgets, allowing you to balance thoroughness with cost and latency. Smaller budgets work well for straightforward tasks, while complex problems benefit from larger thinking allowances that enable more comprehensive analysis.

Vision

Claude's vision capabilities enabled applications that can understand and analyze images alongside text.

The vision system can process multiple image formats including JPEG, PNG, GIF, and WebP, with support for up to 20 images per conversation in the web interface and up to 100 images via API.

Claude can extract information from complex visual content, like reading charts and graphs, analyzing diagrams, interpreting screenshots, and understanding document layouts.

However, understanding the limitations is equally important. Claude cannot identify individuals in photos (by design for privacy protection), may struggle with precise spatial reasoning like reading analog clocks, and should not be relied upon for critical medical image interpretation without professional oversight.

Tool use and function calling

Claude's tool use capabilities transform it from a conversational AI into an orchestration platform capable of interacting with external systems and services. This functionality enables developers to create AI agents that can perform real-world tasks beyond text generation.

The system supports two distinct types of tools. Client tools execute on your systems and include both custom tools you create and Anthropic-provided tools like computer use and text editing capabilities. These tools require implementation on your end but offer flexibility in what Claude can accomplish.

Server tools, like web search, execute on Anthropic's infrastructure and require no implementation from developers. These tools expand Claude's knowledge beyond its training data cutoff and enable real-time information retrieval.

Multilingual support

Claude's multilingual capabilities make it a global platform, supporting development of AI applications across different languages and cultures. The model demonstrates strong performance not just in English, but across major world languages including Spanish, French, German, Italian, Portuguese, Dutch, Polish, Arabic, Japanese, Korean, Chinese, and many others.

This multilingual support extends beyond simple translation to include cultural understanding, context-aware responses, and the ability to maintain conversation quality across language switches.

Models comparison

Understanding the technical details helps us, developers make informed decisions about which Claude model best fits their needs. Here's a comparison of the current Claude model family:

Choosing the right model for your application

Selecting the appropriate Claude model depends on your specific use case, performance requirements, and budget considerations. Each model in the family serves distinct purposes and excels in particular scenarios.

Choose Claude Opus 4 when you need the highest level of intelligence and capability. This model shines at multi-agent frameworks, complex codebase refactoring, nuanced creative writing, and sophisticated financial or scientific analysis. If your application requires sustained performance on long-running tasks or the ability to work continuously for hours, Opus 4 delivers unmatched capability.

Claude Sonnet 4 strikes the optimal balance between intelligence and efficiency. It's ideal for complex customer chatbot inquiries, comprehensive code generation, straightforward agentic loops, and detailed data analysis. Most developers find Sonnet 4 meets their needs while providing faster response times than Opus 4.

Claude 3.5 Haiku serves applications prioritizing speed and cost efficiency. It works well at basic customer support, high-volume formulaic content generation, and straightforward data extraction tasks. When you need AI responses in real-time scenarios or process large volumes of relatively simple queries, Haiku delivers excellent value.

For applications requiring transparency into AI reasoning, models supporting extended thinking (Opus 4, Sonnet 4, and Sonnet 3.7) provide insights into how Claude approaches problems. This capability proves particularly valuable for debugging AI behavior, building trust in AI systems, and optimizing prompts.

Conclusion

Claude represents a sophisticated approach to large language models that prioritizes both capability and safety. From the lightning-fast Haiku for high-volume applications to the powerful Opus 4 for complex reasoning tasks, the model family provides options for virtually any AI-powered application.

The combination of multimodal capabilities, extended thinking, tool use, and strong multilingual support creates a platform that can handle diverse and complex use cases. Whether you're building conversational AI, developing coding assistants, or creating sophisticated analysis tools, Claude's capabilities can significantly enhance your applications.