GLM-5.3-Flash (Reasoning)

by Zhipu AI

GLM-5.3-Flash (Reasoning) is a reasoning model from Zhipu AI, released on August 26, 2026. It has a 1M-token context window and can generate up to 1M output tokens. API pricing is $0.15 per 1M input tokens and $0.5 per 1M output tokens. It ranks #20 of 220 models by Intelligence Score with a score of 48.9.

GLM-5.3-Flash is the first natively multimodal model in Z.AI's GLM-5 series: a 320B-total / 18B-active MoE with hybrid sparse and linear attention (plus mHC), a 1M-token context window, and strong coding and long-horizon agent performance. MIT open weights are on Hugging Face. Launched 2026-08-26 after stealth testing as ox-alpha on OpenRouter and OpenCode. List pricing is $0.15/$0.50 per million input/output tokens (a temporary 50% promo ends 2026-09-09 16:00 UTC).

Key specs

ProviderZhipu AI
Release date2026-08-26
Licenseopen source
Context window1M tokens
Max output1M tokens
Input price$0.15 / 1M tokens
Output price$0.5 / 1M tokens
Intelligence Score48.9
Coding index32.5
Output speed167 tokens/s
Time to first token4.94 s

Quick answers

What is the context window of GLM-5.3-Flash (Reasoning)?

GLM-5.3-Flash (Reasoning) has a context window of 1M tokens, with a maximum output of 1M tokens per response.

How much does GLM-5.3-Flash (Reasoning) cost?

GLM-5.3-Flash (Reasoning) costs $0.15 per 1M input tokens and $0.5 per 1M output tokens through the API.

Is GLM-5.3-Flash (Reasoning) open source?

Yes. GLM-5.3-Flash (Reasoning) is an open model released under the open source license.

When was GLM-5.3-Flash (Reasoning) released?

Zhipu AI released GLM-5.3-Flash (Reasoning) on August 26, 2026.

How does GLM-5.3-Flash (Reasoning) compare to Claude Opus 5.5 (Reasoning)?

GLM-5.3-Flash (Reasoning) scores 48.9 on the Intelligence Score versus 60.5 for Claude Opus 5.5 (Reasoning), the current #1. Input pricing is $0.15 vs $4 per 1M tokens.

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