Claude Sonnet 5.5
- Family
- Claude 5.5
- Released
- 2026-09-28
- Context
- 1M
- Max output
- 128K
- Architecture
- Decoder Only
- Knowledge cutoff
- 2026-06
- Specialization
- general
- Openness
- Proprietary
- License
- ProprietaryRestricted
- Weights
- Not released
- Code
- Unknown
- Training
- Pretrained
Cheapest of 5 routes · Anthropic · cache read $0.100
Cheapest of 5 routes · Anthropic · cache read $0.100
About
Anthropic's Claude Sonnet 5.5, second model in the Claude 5.5 family, released September 28, 2026. First-party positioning: faster, lower-cost complement to Claude Opus 5.5; strongest at well-scoped everyday tasks, bug fixes, and polished documents/slides/spreadsheets; clear upgrade over Claude Sonnet 5 (30%+ faster output; up to 30% less cost per task via fewer tokens — list price unchanged vs Sonnet 5). Claude API id claude-sonnet-5-5. List price $2 per 1M input and $10 per 1M output; cache reads $0.10 / MTok; 5m cache writes $2.50; 1h cache writes $4; Batch API 50% off ($1/$5).
Providers(5)
Compare all 5Compare API pricing across 5 tracked provider routes for input and output tokens, batch, and cached reads when available.
| Provider | Input / 1M | Output / 1M | Batch in / out | Cache | Route |
|---|---|---|---|---|---|
| Anthropic | $2.00 | $10.00 | $1.00 / $5.00 | read $0.100 / 5m $2.50 / 1h $4.00 | Serverless |
| GCP Vertex AI | $2.00 | $10.00 | - | read $0.100 / 5m $2.50 / 1h $4.00 | Serverless |
| Microsoft Foundry | $2.00 | $10.00 | - | read $0.100 / 5m $2.50 / 1h $4.00 | Serverless |
| OpenRouter | $2.00 | $10.00 | - | read $0.100 | Serverless |
| AWS Bedrock | $2.20 | $11.00 | - | read $0.110 / 5m $2.75 / 1h $4.40 | Serverless |
Available via routers & gateways(16)
LiteLLM
GatewayOpen-source Python SDK and proxy server that unifies 100+ LLM APIs behind a single OpenAI-compatible interface, with load balancing, cost tracking, and configurable failover.
OpenRouter
HybridUnified hybrid gateway to 500+ models from 80+ providers via a single OpenAI-compatible API, with an optional Auto Router that selects a model per prompt from market spend data.
Portkey
GatewayProduction AI gateway routing to 1,600+ LLMs with failover, load balancing, caching, and guardrails; MIT-licensed open-source core is self-hostable. Now part of Palo Alto Networks as Prisma AIRS AI Gateway.
AIRouter
RouterCommercial LLM router (branded "AI Router" on its site) that picks the best model per request via a Decision API or an OpenAI-compatible Chat Completions endpoint, with a private selection mode that routes on anonymized patterns; sold as BYOK subscription plans priced by routed tokens.
Amazon Bedrock Intelligent Prompt Routing
RouterAWS Bedrock's native prompt router that predicts each model's performance per request and routes between two models of the same family (Anthropic Claude, Meta Llama or Amazon Nova).
Azure AI Foundry Model Router
RouterMicrosoft Azure AI Foundry's native model router that uses a trained ML model to route each prompt in real time to the optimal Azure-hosted model, with Balanced/Cost/Quality mode selection and automatic failover.
Capabilities
Benchmark peer barsfor Coding
Benchmark scores(9)
| Benchmark | Score | Version | Evaluation | Source |
|---|---|---|---|---|
| 55.5 | CursorBench 4.0Observed 2026-10-05 | Configuration: Sonnet 5.5 Max Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $9.67 Tokens/task: 271,920 Steps/task: 170 Notes: Cursor vendor-reported CursorBench 4.0 configuration result; verified on https://cursor.com/cursorbench chart label 'Sonnet 5.5 Max' (retrieved 2026-10-05). Not independently reproducible. Highest-scoring published configuration selected; timestamp is retrieval date (page carries no per-row date). Cost/tokens/steps from cursor.com/cursorbench table row (same retrieval). | ||
| 52.1 | FrontierCode 1.1 MainObserved 2026-10-05 | Configuration: claude-sonnet-5-5 (Extra High) Harness: claude-code Evaluator: Cognition Confidence: confirmed Notes: Cognition FrontierCode 1.1 Main (100 tasks) mean@5 composite ('new_score'), verified in https://cognition.com/data/frontiercode-leaderboard/data.json (the data file behind https://cognition.com/frontiercode), retrieved 2026-10-05. Agent harness: claude-code. Highest-scoring published effort selected; timestamp is retrieval date. | ||
| 80.5 | FrontierMath Tier 4 v2 (private)Observed 2026-09-29 | Configuration: claude-sonnet-5-5 (Max) Harness: Epoch AI FrontierMath Tier 4 v2 private set Evaluator: Epoch AI Confidence: confirmed Notes: Epoch AI-run evaluation (evaluator of record), from Epoch AI Benchmarking Hub data download https://epoch.ai/data/benchmark_data.zip (file frontiermath_tier_4_v2.csv, row 'claude-sonnet-5-5_max', run started 2026-09-29). Epoch data is CC BY 4.0: credit 'Epoch AI, Capabilities & benchmarking, https://epoch.ai/benchmarks'. Highest-scoring Epoch configuration for this model selected; other configurations exist in the same file. Discovered via Benchmark Heaven (lead only). | ||
| 95.6 | diamondObserved 2026-09-29 | Configuration: claude-sonnet-5-5 (Max) Harness: Epoch AI Inspect harness (GPQA Diamond, 198 Q) Evaluator: Epoch AI Confidence: confirmed Notes: Epoch AI-run evaluation (evaluator of record), from Epoch AI Benchmarking Hub data download https://epoch.ai/data/benchmark_data.zip (file gpqa_diamond.csv, row 'claude-sonnet-5-5_max', run started 2026-09-29). Epoch data is CC BY 4.0: credit 'Epoch AI, Capabilities & benchmarking, https://epoch.ai/benchmarks'. Highest-scoring Epoch configuration for this model selected; other configurations exist in the same file. Discovered via Benchmark Heaven (lead only). | ||
| 61.8 | Terminal-Bench 4.0Observed 2026-10-26 | Configuration: Sonnet 5.5 (max) Harness: Claude Code Evaluator: Terminal-Bench leaderboard Confidence: confirmed Notes: Terminal-Bench official leaderboard (tbench.ai, 4.0 tab, headless-Chrome capture 2026-10-26). Board row: rank 2 'Sonnet 5.5 (max)', agent Claude Code, 61.8% ± 2.9%, dated Sep 28, 2026. Board value used. Anthropic's model page and system card report 70.6% (Claude Code --bare, max effort, safeguards enabled); that is a vendor run and differs from the board. Retrieved 2026-10-26. | ||
| 81.3 | SWE-bench Pro (subset unstated); adaptive thinking, max effort; avg of 5 trialsObserved 2026-10-26 | Configuration: claude-sonnet-5-5 (max effort) Harness: Anthropic system-card standard configuration (scaffold not named); average of five trials Evaluator: Anthropic Confidence: self-reported Notes: Anthropic system card, Table 8.1.A and SWE-bench Pro section. Configuration: adaptive thinking at max effort, default sampling settings, averaged over five trials. The card does not name the agent harness/scaffold or the subset (public vs commercial). Sentence: 'Sonnet 5.5 achieved 81.3%.' Harness not stated in the system card. Retrieved 2026-10-26. | ||
| 1478.0 | text_style_control overall 2026-10-22 (style control, default view)Observed 2026-10-26 | Configuration: Claude Sonnet 5.5 (xHigh) Harness: LMArena blind pairwise human votes, Bradley-Terry Evaluator: LMArena Confidence: confirmed Notes: LMArena text style control leaderboard, overall category, published 2026-10-22 (HF lmarena-ai/leaderboard-dataset @9761a3ce, latest split). Board entry 'Claude Sonnet 5.5 (xHigh)': rank 29, Arena Score 1477.5 (95% CI 1470.5-1484.5), 8977 votes. Retrieved 2026-10-26. | Source Source: LMArena (lmarena.ai), CC BY 4.0 | |
| 1265.0 | vision_style_control overall 2026-10-19 (style control, default view)Observed 2026-10-26 | Configuration: Claude Sonnet 5.5 (xHigh) Harness: LMArena blind pairwise human votes, Bradley-Terry Evaluator: LMArena Confidence: confirmed Notes: LMArena vision style control leaderboard, overall category, published 2026-10-19 (HF lmarena-ai/leaderboard-dataset @9761a3ce, latest split). Board entry 'Claude Sonnet 5.5 (xHigh)': rank 40, Arena Score 1264.9 (95% CI 1252.4-1277.5), 2564 votes. Retrieved 2026-10-26. | Source Source: LMArena (lmarena.ai), CC BY 4.0 | |
| 1468.0 | text creative_writing 2026-10-22Observed 2026-10-22 | Configuration: Claude Sonnet 5.5 (xHigh) Harness: LMArena blind pairwise human votes, Bradley-Terry Evaluator: LMArena Confidence: confirmed Notes: LMArena Text arena, Creative Writing category (no style control), board published 2026-10-22 (HF lmarena-ai/leaderboard-dataset @a467e6b9, text config, latest split). Board entry 'Claude Sonnet 5.5 (xHigh)' (category creative_writing in text/latest-00000-of-00001.parquet): rank 18 of 416, rating 1468.3 (95% CI 1454.2-1482.4), 2058 votes. Source: LMArena (CC BY 4.0). Retrieved 2026-10-27. | Source Source: LMArena (lmarena.ai), CC BY 4.0 |
Migration checks
No linked migration route is available for this model yet.
API versions
claude-sonnet-5-5Claude Sonnet 5.5Sonnet 5.5