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Model detail

claude-sonnet-4-5-20250929

Provided by Anthropic
Pay-as-you-go

Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with improvements across system design, code security, and specification adherence. The model is designed for extended autonomous operation, maintaining task continuity across sessions and providing fact-based progress tracking. Sonnet 4.5 also introduces stronger agentic capabilities, including improved tool orchestration, speculative parallel execution, and more efficient context and memory management. With enhanced context tracking and awareness of token usage across tool calls, it is particularly well-suited for multi-context and long-running workflows. Use cases span software engineering, cybersecurity, financial analysis, research agents, and other domains requiring sustained reasoning and tool use.

Model specs

Context length
200K
Max output
64K
I/O modalities
Text / Image
Released
2025-09

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API endpoints

One MixRoute gateway, OpenAI-compatible

  • Anthropic Messages /v1/messages POST
  • OpenAI-compatible /v1/chat/completions POST

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Pricing

Flat rate, unit: /1M Tokens

Input

$3.0000 /1M Tokens

Completion

$15.0000 /1M Tokens

Cache read

$0.3000 /1M Tokens

Cache creation

$3.7500 /1M Tokens

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Selection summary

Quickly judge whether it fits your workload

What is this model good for?

Real-world agents and coding with state-of-the-art performance

Use Claude Sonnet 4.5 for software engineering, cybersecurity, financial analysis, and research agents. It delivers state-of-the-art coding performance with improved tool orchestration and context management.

What should you check before using it?

Test extended autonomous operation and tool orchestration

Sonnet 4.5 supports extended autonomous operation with fact-based progress tracking. Test speculative parallel execution and context management for long-running workflows.

Why use it through MixRoute?

Use the compatible endpoint with stable model ID

Use the confirmed compatible endpoint with model ID claude-sonnet-4-5 through MixRoute.

08

Token cost estimator

Live estimate from this page's pricing, not an actual bill

Share of the same prefix read repeatedly, up to 100%

09

FAQ

Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on SWE-bench Verified with improved tool orchestration and context management.

One endpoint, a testable decision

Test this model and alternate routes with the same request format

Start from a real workload, then let quality, total cost, and failure conditions decide whether to send production traffic.