Claude Sonnet 5.5

Chat Completions

claude-sonnet-5.5

Anthropic|Created Sep 29, 2026|1M context

Chat Completions

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.

Overview Specifications Activity Performance Uptime Examples API Reference

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Pricing-50%

Pay-as-you-go rates for this model. More details in the billing guide.

Input Tokens (1M)

$1.00

Cached Input Tokens (1M)

$0.10

Output Tokens (1M)

$5.00

Capabilities

Input Modalities

TextImageFile

Output Modalities

Text

Supported Parameters

Available parameters for API requests

Frequency PenaltyLogit BiasMax Completion TokensPresence PenaltyReasoning EffortResponse FormatStopTool ChoiceToolsParallel Tool CallsTemperatureTop PPrediction