Model Overview & Capabilities
GLM-5.3 Fast is Zhipu AI’s (Z.ai) specialized ultra-low-latency serving model introduced in October 2026, capturing Rank #17 on our leaderboard with a composite index score of 39.8. Engineered specifically for real-time developer feedback loops, GLM-5.3 Fast achieves an industry-leading generation speed of 490 tokens per second while maintaining solid reasoning scores of 40.2% on SWE-bench Verified, 39.5% on Terminal-Bench 2.0, and 40.5% on Aider Polyglot.
The model is priced at $0.20 per million input tokens and $2.60 per million output tokens, resulting in an effective blended cost of $0.80 per million tokens under 3:1 input:output ratios and achieving a cost efficiency of $0.0201 per index point. Its standout technical metric is an ultra-fast 0.42-second time to first token, ensuring immediate responses during interactive IDE tasks.
Equipped with an expansive 1,000,000-token context window and up to 32,768 output tokens, GLM-5.3 Fast is the ideal backend engine for interactive autocomplete plugins, inline code generation, rapid syntax validation, automated linting scripts, and low-latency voice-driven developer assistants operating under tight latency budgets.
