Gemini 3.5 Flash vs GLM 5.1: side-by-side summary

Gemini 3.5 Flash and GLM 5.1 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

Gemini 3.5 Flash, from Google, has a 1,048,576-token context window and is priced at $1.50/M tokens input, $9/M tokens output on OpenRouter.

GLM 5.1, from Z.ai, has a 204,800-token context window and is priced at $0.9086/M tokens input, $2.856/M tokens output on OpenRouter.

Context window

• Gemini 3.5 Flash: 1,048,576 tokens
• GLM 5.1: 204,800 tokens

Price

• Gemini 3.5 Flash: $1.50/M tokens input, $9/M tokens output
• GLM 5.1: $0.9086/M tokens input, $2.856/M tokens output

Provided by

• Gemini 3.5 Flash: Google
• GLM 5.1: Z.ai

• Gemini 3.5 Flash model details, providers and pricing
• GLM 5.1 model details, providers and pricing