GPT-5.5 vs LongCat-2.0

GPT-5.5 leads in 2 of 8 categories

Arena ELO

Tie

Cheaper

GPT-5.5

Faster

Tie

Detailed Comparison

Category	GPT-5.5	LongCat-2.0
Provider	OpenAI	Meituan
Context Window	128K	128K
Input Price ($/1M)	$5 WIN	N/A
Output Price ($/1M)	$30 WIN	N/A
Arena ELO	N/A	N/A
Coding	N/A	N/A
Reasoning	N/A	N/A
Speed (tokens/sec)	N/A	N/A
Open Source	No	Yes

Frequently Asked Questions

Which has a larger context window?

GPT-5.5 supports 128K context, while LongCat-2.0 supports 128K.

Is GPT-5.5 or LongCat-2.0 open source?

GPT-5.5 is proprietary. LongCat-2.0 is open source.

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