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.

S2.1 ProFish Audio Remove
GPT-6 LunaOpenAI Remove
Claude Opus 5.5Anthropic Remove
Transcribe 1 ProFish Audio Remove

4 is the maximum. Remove one to add another.

s2.1-pro vs gpt-6-luna vs claude-opus-5.5 vs transcribe-1-pro
Attribute	S2.1 Pros2.1-pro	GPT-6 Lunagpt-6-luna	Claude Opus 5.5claude-opus-5.5	Transcribe 1 Protranscribe-1-pro
Pricing
Input	$0 / 1M	$0.10 / 1M	$4.00 / 1M	$0 / 1M
Output	$0 / 1M	$0.50 / 1M	$20.00 / 1M	$0 / 1M
Cache Write (5m)	Not applicable	$0.10 / 1M	$5.00 / 1M	Not applicable
Cache Write (1h)	Not applicable	$0.10 / 1M	$8.00 / 1M	Not applicable
Cache Read	Not applicable	$0.10 / 1M	$0.40 / 1M	Not applicable
Web Search	$0 / 1M	$0 / 1M	$0 / 1M	$0 / 1M
Context
Max context	N/A	1.1M	1M	N/A
Max output	N/A	N/A	N/A	N/A
Capabilities
Vision	No	Yes	Yes	No
Function Calling	No	Yes	Yes	No
JSON Mode	No	Yes	Yes	No
Streaming	No	Yes	Yes	No
Catalogue
Provider	Fish Audio	OpenAI	Anthropic	Fish Audio
Category	voice	chat	chat	voice
Charge type	Pay As You Go	Pay As You Go	Pay As You Go	Pay As You Go
Released	2026-07-29	—	—	2026-09-24
Description
Summary	Fish Audio S2.1 Pro text-to-speech. Billed per UTF-8 byte of input text.	GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, optimized for high-volume and latency-sensitive workloads such as chat, classification, and lightweight agentic tasks. It combines low-cost, responsive inference with the GPT-6 family’s improvements in factual reliability and clear, concise communication. At higher reasoning effort, GPT-6 Luna can also handle complex software engineering and computer-use workflows that previously required a Sol-tier model, making it a versatile choice for scalable production applications that need to balance speed, cost, and capability.	Claude Opus 5.5 is Anthropic's flagship model for advanced reasoning, coding, and long-horizon agentic workflows, succeeding Opus 5. It excels at multi-step changes across large codebases, code review and bug detection, financial and scientific analysis, and understanding dense charts, diagrams, and screenshots, with stronger grounding when reporting figures and citing sources. Compared with Opus 5, it completes comparable tasks with fewer steps and lower token usage while providing clearer, more concise progress reporting. With adaptive thinking and configurable effort levels, Opus 5.5 can balance reasoning depth, latency, and cost, making it well suited for both demanding autonomous workflows and latency-sensitive professional tasks.	Fish Audio Transcribe 1 Pro speech-to-text with speaker labels; transcripts include speaker tags such as <\|speaker:0\|>. Billed per second of audio.