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claude-sonnet-5.5 vs s2.1-pro vs universal-3-5-pro vs perceptron-mk1.5
Attribute	Claude Sonnet 5.5claude-sonnet-5.5	S2.1 Pros2.1-pro	Universal-3.5 Prouniversal-3-5-pro	Perceptron Mk1.5perceptron-mk1.5
Pricing
Input	$2.00 / 1M	$0 / 1M	$0 / 1M	$0.15 / 1M
Output	$10.00 / 1M	$0 / 1M	$0 / 1M	$1.50 / 1M
Cache Write (5m)	$2.50 / 1M	Not applicable	Not applicable	$0.15 / 1M
Cache Write (1h)	$4.00 / 1M	Not applicable	Not applicable	$0.15 / 1M
Cache Read	$0.20 / 1M	Not applicable	Not applicable	$0.15 / 1M
Web Search	$0 / 1M	$0 / 1M	$0 / 1M	$0 / 1M
Context
Max context	1M	N/A	N/A	36.9K
Max output	N/A	N/A	N/A	N/A
Capabilities
Vision	Yes	No	No	No
Function Calling	Yes	No	No	No
JSON Mode	Yes	No	No	No
Streaming	Yes	No	No	Yes
Catalogue
Provider	Anthropic	Fish Audio	AssemblyAI	Perceptron
Category	chat	voice	voice	chat
Charge type	Pay As You Go	Pay As You Go	Pay As You Go	Pay As You Go
Released	—	2026-07-29	2026-09-22	2026-09-25
Description
Summary	Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, serving as a direct upgrade to Sonnet 5. It excels at feature development, bug fixing, and creating polished documents, presentations, and spreadsheets, while offering clearer writing and communication than its predecessor.	Fish Audio S2.1 Pro text-to-speech. Billed per UTF-8 byte of input text.	AssemblyAI Universal-3.5 Pro speech-to-text. Billed per second of audio.	Perceptron Mk1.5 chat model that accepts audio input. Audio and text input are billed per token.