GPT-5.5 vs GLM-5.1

OpenAI's GPT-5.5 and Zhipu AI's GLM-5.1 compared on specs, pricing, and capabilities — as configured in AI Crucible ensembles.

GLM-5.1 input tokens are 3.6x cheaper than GPT-5.5 ($1.68 vs $6.00 per 1M tokens).
GLM-5.1 output tokens are 6.8x cheaper than GPT-5.5 ($5.28 vs $36.00 per 1M tokens).
GPT-5.5 offers the larger context window: 1.05M tokens vs 203K tokens for GLM-5.1.
GPT-5.5 accepts image inputs; GLM-5.1 is text-only in AI Crucible.

Specification	GPT-5.5	GLM-5.1
Provider	OpenAI	Zhipu AI
API model ID	gpt-5.5	zai-org/GLM-5.1
Description	OpenAI's flagship model with adaptive reasoning, 1M context, and native multimodal intelligence.	Z.AI's most advanced GLM model, optimized for long-horizon agentic tasks with interleaved reasoning.
Context window	1.05M tokens	203K tokens
Max output tokens	128,000	65,536
Input cost ($/1M tokens)	$6.00	$1.68
Output cost ($/1M tokens)	$36.00	$5.28
Cache read cost ($/1M tokens)	$0.60	-
Latency	medium	medium
Reasoning model	Yes	Yes
Vision (image input)	Yes	No
Tool use	Yes	Yes