Released on August 18, 2026, by Z AI, GLM-5.3 (max) is an open-weights reasoning model utilizing a Mixture of Experts (MoE) architecture. The model features a massive 753 billion total parameters, with 40 billion active parameters used during inference. It supports a 1M token context window and processes text-only inputs and outputs. In performance benchmarks, GLM-5.3 (max) achieved a score of 45 on the Artificial Analysis Intelligence Index, significantly outperforming the median score of 18 for comparable models. However, this intelligence comes at a high computational and financial cost. The model is notably verbose, generating 210M tokens during Intelligence Index evaluations compared to the 140M token median. Its throughput is also below average at 60 tokens per second, with a time to first token (TTFT) of 3.45s, trailing the median of 2.38s. Pricing via Z AI's API is substantial, costing $1.40 per 1M input tokens and $4.40 per 1M output tokens—well above the medians of $0.47 and $1.69, respectively. Consequently, the average cost to evaluate a single task on the Intelligence Index is $2.01.