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Anthropic: Claude Sonnet 4.5

anthropic/claude-sonnet-4.5

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.

Modalities
In / out price
$3 / $15per 1M
Context
1.0M
Released
Sep 29, 2025
Knowledge cutoff
Jan 2025

Providers

Different companies host the same model. OpenRouter routes your request to one of them based on the routing mode you pick: Balanced (price + speed), Nitro (fastest), or Floor (cheapest).

Pricing

The average price customers actually pay for this model, next to the prices providers post. Caching and discounts mean the price actually paid is often well below the listed one.

Weighted average

Input
$1.871/M tokens
Output
$15/M tokens
Price history
No effective price data for this selection

Performance

Throughput is how fast the model writes (tokens per second — higher is better). Latency is total round-trip time (lower is better). TTFT is time-to-first-token — how long before you see anything appear (lower is better).

Throughput
47tok/s

P50, best across providers

Latency
0.62s

P50, best provider

AutoExacto benchmarks
GPQA DiamondTAU-BenchAnthropic82.1%76.2%auto-routing82.0%73.9%Amazon Bedrock81.5%73.3%Amazon Bedrock (EU)81.1%73.4%Claude Platform on AWS80.2%73.9%Azure81.5%72.5%
+1 more providers

Uptime

Uptime is the percentage of the past 3 days that at least one provider was responding to requests. Availability is the percentage of time that inference was successfully served. OpenRouter continuously monitors and uses the next-best provider when one returns an error.

Uptime (3d)The model was reachable. Request routed to a provider.
100.00%
Availability (3d)The model returned inference from any provider. Errors and empty responses count against it.
99.79%

Availability over the last 3 days

Last 72 hours
Availability 99.79%
3 Days Ago2 Days AgoYesterdayNow

Availability over the last 24 hours

OpenRouter Availability
99.65%
Without Routing
97.58%

When an error occurs in an upstream provider, we can recover by routing to another healthy provider, if your request filters allow it. You can access per-provider uptime data programmatically through the Endpoints API. Learn more about our load balancing and provider routing options.

Benchmarks

Scores on standardized evaluations and this model’s own outputs on shared benchmark prompts. Higher percentages are better — and each rank shows where this model lands among the models evaluated on that source.

Benchmark score summary for Anthropic: Claude Sonnet 4.5 (Artificial Analysis, Design Arena and Vals AI)
SourceBenchmarkScore
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) GPQA Diamond72.7%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) HLE7.2%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) IFBench42.7%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) τ²-Bench Telecom70.5%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) AA-LCR54.0%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) CritPt0.0%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) LiveCodeBench59.0%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) Terminal-Bench Hard28.8%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) MMLU-Pro86.0%
Artificial AnalysisClaude 4.5 Sonnet (Non-reasoning) AIME 202537.0%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) Coding Index52.1
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) Agentic Index15.8
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) GPQA Diamond83.4%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) HLE17.8%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) IFBench57.3%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) τ²-Bench Telecom78.1%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) AA-LCR72.3%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) τ-Bench Banking24.5%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) GDPval-AA20.8%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) CritPt1.1%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) LiveCodeBench71.4%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) SciCode45.7%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) Terminal-Bench Hard35.6%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) Terminal-Bench 4.00.0%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) Terminal-Bench 2.155.8%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) MMLU-Pro87.5%
Artificial AnalysisClaude 4.5 Sonnet (Reasoning) AIME 202588.0%
Design ArenaClaude Sonnet 4.5 Models Arena 3D Elo1137
Design ArenaClaude Sonnet 4.5 Models Arena Asciiart Elo1170
Design ArenaClaude Sonnet 4.5 Models Arena Code Categories Elo1172
Design ArenaClaude Sonnet 4.5 Models Arena Data Visualization Elo1164
Design ArenaClaude Sonnet 4.5 Models Arena Game Development Elo1155
Design ArenaClaude Sonnet 4.5 Models Arena SVG Elo1097
Design ArenaClaude Sonnet 4.5 Models Arena UI Component Elo1151
Design ArenaClaude Sonnet 4.5 Models Arena Website Elo1181
Design ArenaClaude Sonnet 4.5 Agents Arena Full Stack Elo1025
Design ArenaClaude Sonnet 4.5 Agents Arena Mobile Apps Elo1131
Design ArenaClaude Sonnet 4.5 Agents Arena Webapps Elo1037
Vals AIClaude Sonnet 4.5 (Nonthinking) CorpFin v260.8%
Vals AIClaude Sonnet 4.5 (Nonthinking) Finance Agent v149.2%
Vals AIClaude Sonnet 4.5 (Nonthinking) MedCode40.6%
Vals AIClaude Sonnet 4.5 (Nonthinking) MedScribe84.5%
Vals AIClaude Sonnet 4.5 (Nonthinking) SAGE v132.9%

Apps

Public apps that send the most traffic to this model. Good signal for what real production workloads look like — and a hint at which use cases this model is best suited for.

1.
9.34Btokens
2.
Favicon for https://janitorai.com/
Janitor AI
8.2Btokens
3.
Favicon for https://claude.ai/apple-touch-icon.png
Claude Code
8.17Btokens
4.
Favicon for https://openclaw.ai/
OpenClaw
6.74Btokens
5.
Favicon for https://sillytavern.app/
SillyTavern
6.55Btokens
Rest of OpenRouter
1.58B
Top 5 Apps
195M

Activity

Token volume and request traffic to this model over time.

API

Drop-in code to call this model. OpenRouter's API is OpenAI-compatible — most SDKs work by just swapping the base URL. The only thing that changes between models is the model slug below.

Available through EU in-region routing

Anthropic: Claude Sonnet 4.5 is available through EU in-region routing. Requests sent to eu.openrouter.ai are decrypted in the EU and routed only to shared provider endpoints in Europe (the EU/EEA, the UK, and Switzerland).

Providers in Europe
Amazon Bedrock
Prices in Europe
  • Amazon Bedrock: $3.30/M tokens input, $16.50/M tokens output
Base URL
https://eu.openrouter.ai/api/v1
Plan
Requires Business or Enterprise. Self-serve on Business: no contract, no monthly minimum. OpenRouter Business for EU in-region routing

Fails closed: if no shared provider endpoint in Europe is available, the request errors instead of leaving the region. Requests served by your own BYOK key go to your deployment’s region, which you control. In-region routing docs

Frequently asked questions