Anthropic

Claude Sonnet 5.5

anthropic/claude-sonnet-5.5
Released Sep 28, 2026Commercial
ThinkingToolsVisioncommercial cloud

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...

Cost / 1M tokens

High usage

$2.00

input

$0.10

cached input

$10.00

output

Context Window

1M

Up to 128K max output

Modalities

text, image, file → text

Claude tokenizer

Quickstart & API

anthropic/claude-sonnet-5.5
Open the model picker in ChatOSS Desktop (Code, Kanban, or Chat) and select or paste this model ID.

Best for & Strengths

Key Strengths

92.4% Vibe Code Bench v1.169.8% Code Migration64.1% Terminal-Bench 4.0Half the cost of Opus 5.5

Recommended Workloads in ChatOSS

  • Daily agentic coding
  • Full-stack feature delivery
  • Code migrations & upgrades
Available in ChatOSS Code, Kanban Orchestrate, and Chat modes via Plus, Max, or BYOK.

Verified Evaluations

Benchmarks & Frontier Comparison

How Claude Sonnet 5.5 compares against leading open-weight and proprietary frontier models across independent agentic coding and reasoning suites.

View full Top 40 Leaderboard →
Claude Sonnet 5.5DeepSeek V4.1 FlashGLM 5.3Kimi K3.1 Pro
Benchmark (Metric)Claude Sonnet 5.5DeepSeek V4.1 FlashGLM 5.3Kimi K3.1 ProClaude Opus 5.5
Agentic & Software Engineering
ChatOSS Agentic Coding Index (%)74.3%63.2%58.3%65%74.1%
SWE-Bench Verified (%)—91.5%95.4%94.8%97%
DeepSWE v1.1 (Pass@1 %)71%77%69%73.5%74.2%
Vibe Code Bench v1.1 (%)92.39%87.7%78.1%88.4%90.3%
Terminal-Bench 4.0 (%)64.14%42.3%42%46.2%65.2%
Code Migration (%)69.83%45.6%44.2%52%66.7%
Intelligence & Token Economics
Artificial Analysis Intelligence Index (0–100)54.539.544.855.157.6
Input Price (/ 1M tokens)$2.00$0.15$1.40$2.00$4.00
Output Price (/ 1M tokens)$10.00$0.60$4.40$10.00$20.00

ChatOSS Agentic Coding Index

ChatOSS Benchmark Audit · 4-benchmark composite mean

74.3%

DeepSWE v1.1

DeepSWE / Official Audit · Mini-SWE-Agent

71%

Vibe Code Bench v1.1

Vals.ai · OpenHands

92.39%

Terminal-Bench 4.0

Vals.ai / Artificial Analysis · Terminus 2

64.14%

Code Migration

Vals.ai · Vals evaluation harness

69.83%

Artificial Analysis Intelligence Index

Artificial Analysis

54.5

Design Arena: ANDROIDNATIVE

Design Arena · Rank #6 (58.8% win)

1264 Elo

Design Arena: BLENDER3D

Design Arena · Rank #3 (59.4% win)

1265 Elo

Design Arena: CODETOVIDEO

Design Arena · Rank #2 (72.3% win)

1332 Elo

Design Arena: MOBILEAPPS

Design Arena · Rank #5 (57.7% win)

1263 Elo

Active Provider Endpoints (10)

Upstream inference providers serving Claude Sonnet 5.5, with per-provider pricing, context limits, quantization, and 24-hour uptime.

ProviderInput / 1MOutput / 1MCache Read / 1MContextMax OutputQuantizationUptime (24h)
Google
google-vertex/global
$2.00$10.00$0.101M128K—100.0%
Amazon Bedrock
amazon-bedrock
$2.00$10.00$0.101M128K—100.0%
Azure
azure/global
$2.00$10.00$0.101M128K—100.0%
Claude Platform on AWS
claude-on-aws
$2.00$10.00$0.101M128K—100.0%
Anthropic
anthropic
$2.00$10.00$0.101M128K—100.0%
Amazon Bedrock
amazon-bedrock/eu-west-1
$2.20$11.00$0.111M128K—100.0%
Amazon Bedrock
amazon-bedrock/us-east-1
$2.20$11.00$0.111M128K—100.0%
Google
google-vertex/us
$2.20$11.00$0.111M128K—100.0%
Azure
azure/us
$2.20$11.00$0.111M128K—100.0%
Google
google-vertex/europe
$2.20$11.00$0.111M128K—100.0%

Supported API Parameters

Parameters accepted by this model when called through ChatOSS or OpenRouter.

include_reasoningmax_completion_tokensmax_tokensreasoningreasoning_effortresponse_formatstopstructured_outputstool_choicetoolsverbosity

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