Compare models

Put up to 4 models beside each other — token prices, context windows, capabilities and provider, from the same catalogue the model pages read.

Claude Sonnet 5.5Anthropic Remove
S2 ProFish Audio Remove
S1Fish Audio Remove
GPT-6 Astra ProOpenAI Remove

4 is the maximum. Remove one to add another.

claude-sonnet-5.5 vs s2-pro vs s1 vs gpt-6-astra-pro
Attribute	Claude Sonnet 5.5claude-sonnet-5.5	S2 Pros2-pro	S1s1	GPT-6 Astra Progpt-6-astra-pro
Pricing
Input	$2.00 / 1M	$0 / 1M	$0 / 1M	$10.00 / 1M
Output	$10.00 / 1M	$0 / 1M	$0 / 1M	$50.00 / 1M
Cache Write (5m)	$2.50 / 1M	Not applicable	Not applicable	$10.00 / 1M
Cache Write (1h)	$4.00 / 1M	Not applicable	Not applicable	$10.00 / 1M
Cache Read	$0.20 / 1M	Not applicable	Not applicable	$10.00 / 1M
Web Search	$0 / 1M	$0 / 1M	$0 / 1M	$0 / 1M
Context
Max context	1M	N/A	N/A	1M
Max output	N/A	N/A	N/A	N/A
Capabilities
Vision	Yes	No	No	Yes
Function Calling	Yes	No	No	Yes
JSON Mode	Yes	No	No	Yes
Streaming	Yes	No	No	Yes
Catalogue
Provider	Anthropic	Fish Audio	Fish Audio	OpenAI
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	2026-07-29	—
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 Pro text-to-speech. Billed per UTF-8 byte of input text.	Fish Audio S1 text-to-speech. Billed per UTF-8 byte of input text.	GPT-6 Astra Pro uses the same underlying model as GPT-6 Astra, but runs with reasoning.mode set to pro for higher-quality responses on complex tasks. Optimized for deeper reasoning, greater accuracy, and more reliable multi-step execution, it is well suited for demanding coding, analysis, and agentic workflows where solution quality takes priority over speed and cost.