GLM 5.3 vs GPT-5.6 Luna: side-by-side summary

GLM 5.3 and GPT-5.6 Luna 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.

GPT-5.6 Luna, from OpenAI, has a 1,050,000-token context window and is priced at $0.20/M tokens input, $1.20/M tokens output on OpenRouter.

Context window

• GLM 5.3: 1,048,576 tokens
• GPT-5.6 Luna: 1,050,000 tokens

Price

• GLM 5.3: $1.40/M tokens input, $4.40/M tokens output
• GPT-5.6 Luna: $0.20/M tokens input, $1.20/M tokens output

Provided by

• GLM 5.3: Z.ai
• GPT-5.6 Luna: OpenAI

• GLM 5.3 model details, providers and pricing
• GPT-5.6 Luna model details, providers and pricing