Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade. It is especially strong at building features, fixing bugs, and producing polished documents, slides, and spreadsheets, and it writes and communicates more clearly than its predecessor.
Thinking is always on, so effort is the main lever for trading off depth, latency, and cost, and lower effort settings keep it responsive for everyday agentic loops.
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).
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.
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).
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.
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.
| Source | Benchmark | Score |
|---|---|---|
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) Intelligence Index | 35.9 |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) HLE | 36.2% |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) AA-LCR | 76.0% |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) GDPval-AA | 33.8% |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) CritPt | 11.4% |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) SciCode | 49.1% |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) Terminal-Bench 4.0 | 20.7% |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) AA-Omniscience Accuracy | 46.3% |
| Artificial Analysis | Claude Sonnet 5.5 (Low, Default Fallback) AA-Omniscience Non-Hallucination Rate | 49.8% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) Intelligence Index | 56.0 |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) HLE | 55.0% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) AA-LCR | 82.7% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) GDPval-AA | 66.9% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) CritPt | 31.4% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) SciCode | 61.0% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) Terminal-Bench 4.0 | 63.6% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) AA-Omniscience Accuracy | 53.9% |
| Artificial Analysis | Claude Sonnet 5.5 (Max, Default Fallback) AA-Omniscience Non-Hallucination Rate | 53.0% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) Intelligence Index | 46.8 |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) HLE | 45.8% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) AA-LCR | 78.0% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) GDPval-AA | 52.5% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) CritPt | 24.6% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) SciCode | 53.7% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) Terminal-Bench 4.0 | 43.9% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) AA-Omniscience Accuracy | 52.0% |
| Artificial Analysis | Claude Sonnet 5.5 (High, Default Fallback) AA-Omniscience Non-Hallucination Rate | 35.4% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) Intelligence Index | 51.9 |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) HLE | 50.0% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) AA-LCR | 79.7% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) GDPval-AA | 61.4% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) CritPt | 31.1% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) SciCode | 57.3% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) Terminal-Bench 4.0 | 57.1% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) AA-Omniscience Accuracy | 53.0% |
| Artificial Analysis | Claude Sonnet 5.5 (Xhigh, Default Fallback) AA-Omniscience Non-Hallucination Rate | 37.1% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) Intelligence Index | 40.8 |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) HLE | 39.8% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) AA-LCR | 76.3% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) GDPval-AA | 41.2% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) CritPt | 16.9% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) SciCode | 52.9% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) Terminal-Bench 4.0 | 29.8% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) AA-Omniscience Accuracy | 47.2% |
| Artificial Analysis | Claude Sonnet 5.5 (Medium, Default Fallback) AA-Omniscience Non-Hallucination Rate | 48.8% |
| Design Arena | Claude Sonnet 5.5 Agents Arena Mobile Apps Elo | 1265 |
| Design Arena | Claude Sonnet 5.5 Agents Arena Spreadsheet Elo | 1245 |
| Design Arena | Claude Sonnet 5.5 Agents Arena Webapps Elo | 1302 |
| Design Arena | Claude Sonnet 5.5 Models Arena 3D Elo | 1458 |
| Design Arena | Claude Sonnet 5.5 Models Arena Code Categories Elo | 1364 |
| Design Arena | Claude Sonnet 5.5 Models Arena Data Visualization Elo | 1391 |
| Design Arena | Claude Sonnet 5.5 Models Arena Game Development Elo | 1467 |
| Design Arena | Claude Sonnet 5.5 Models Arena UI Component Elo | 1368 |
| Design Arena | Claude Sonnet 5.5 Models Arena Website Elo | 1326 |
| Vals AI | Claude Sonnet 5.5 ClaimBench | 100.0% |
| Vals AI | Claude Sonnet 5.5 Code Migration v1.1 | 86.9% |
| Vals AI | Claude Sonnet 5.5 CyberBench v1.1 | 59.6% |
| Vals AI | Claude Sonnet 5.5 EMB v1.1 | 75.9% |
| Vals AI | Claude Sonnet 5.5 Finance Agent v2.1 | 67.3% |
| Vals AI | Claude Sonnet 5.5 HLAB-Vals-1.1 | 10.4% |
| Vals AI | Claude Sonnet 5.5 IOI | 83.1% |
| Vals AI | Claude Sonnet 5.5 Legal Research Bench | 48.1% |
| Vals AI | Claude Sonnet 5.5 MedCode | 52.9% |
| Vals AI | Claude Sonnet 5.5 MedScribe | 91.1% |
| Vals AI | Claude Sonnet 5.5 ProgramBench | 6.5% |
| Vals AI | Claude Sonnet 5.5 ProofBench v1.1 | 100.0% |
| Vals AI | Claude Sonnet 5.5 SAGE | 51.8% |
| Vals AI | Claude Sonnet 5.5 Vals Science Index | 59.1% |
| Vals AI | Claude Sonnet 5.5 SRE Bench | 30.2% |
| Vals AI | Claude Sonnet 5.5 SWE-bench Multimodal | 58.3% |
| Vals AI | Claude Sonnet 5.5 Tax Agent Bench | 42.0% |
| Vals AI | Claude Sonnet 5.5 Terminal-Bench 4.0 | 64.1% |
| Vals AI | Claude Sonnet 5.5 Vals Index | 70.9% |
| Vals AI | Claude Sonnet 5.5 Vibe Code Bench v1.1 | 92.4% |
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.
Token volume and request traffic to this model over time.
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.
Anthropic: Claude Sonnet versions
Not currently available through EU in-region routing. In-region routing docs
Guides, cookbooks, blog posts, and tools for building with Anthropic: Claude Sonnet 5.5 (batch) on OpenRouter.
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade. It is especially strong at building features, fixing bugs, and producing polished documents, slides, and spreadsheets, and it writes and communicates more clearly than its predecessor.
The Claude Sonnet 5.5 (batch) documentation on OpenRouter includes the Claude 5.5 Migration Guide cookbook. The quickstart covers API keys and your first request, and the API reference lists every parameter.
Claude Sonnet 5.5 (batch) costs $1.00/M input tokens and $5.00/M output tokens, with separate rates for Cache Read at $0.05/M tokens, Cache Write at $1.25/M tokens, Cache Write (1h) at $2.00/M tokens, and Web Search at $10.00/1K calls.
Claude Sonnet 5.5 (batch) has a 1,000,000 token context window. It supports up to 128,000 completion tokens.
Yes. Claude Sonnet 5.5 (batch) accepts tools and tool_choice for function calling. It also supports structured outputs via a JSON schema in response_format.
Claude Sonnet 5.5 (batch) accepts text, images, and files such as PDFs as input and returns text.
Claude Haiku 5.5, Claude Opus 5.5, Claude Fable 5.1 and 11 more are other text models from Anthropic.
Claude Sonnet 5.5 (batch) was released on September 28, 2026.