GLM 5.3 vs Claude Opus 5 (Fast): side-by-side summary

GLM 5.3 and Claude Opus 5 (Fast) are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

GLM 5.3, from Z.ai, has a 1,048,576-token context window and is priced at $1.40/M tokens input, $4.40/M tokens output on OpenRouter.

Claude Opus 5 (Fast), from Anthropic, has a 1,000,000-token context window and is priced at $10/M tokens input, $50/M tokens output on OpenRouter.

Context window

• GLM 5.3: 1,048,576 tokens
• Claude Opus 5 (Fast): 1,000,000 tokens

Price

• GLM 5.3: $1.40/M tokens input, $4.40/M tokens output
• Claude Opus 5 (Fast): $10/M tokens input, $50/M tokens output

Provided by

• GLM 5.3: Z.ai
• Claude Opus 5 (Fast): Anthropic

• GLM 5.3 model details, providers and pricing
• Claude Opus 5 (Fast) model details, providers and pricing