GLM 5.3 FlashX: pricing, context and benchmarks

What you need to know about GLM 5.3 FlashX

Z.ai (Zhipu), based in China, put GLM 5.3 FlashX online on September 18, 2026. It accepts text, images, and video as input and produces text. Its context window reaches 1,048,576 tokens, larger than 93 % of the models in the registry, and it can write up to 131,072 tokens in one go.

It is a recent model: real-world feedback and independent scores are still scarce.

GLM 5.3 FlashX pricing

On OpenRouter, GLM 5.3 FlashX costs $0.37 per million input tokens and $1.25 per million output tokens. Counting three tokens read for every token written, its average price is $0.59 per million, more expensive than 45 % of paid models (1.3 times cheaper than the median of $0.76).

A concrete example: a task that sends 2,000 tokens (about 1,500 words) and receives a 500-token answer costs $0.0014. At 1,000 tasks a day, budget $41 a month. The price calculator redoes this with your own volumes.

Tokens already sent and cached are billed at $0.09 per million.

Performance and benchmarks

Epoch AI does not yet publish a capabilities index for GLM 5.3 FlashX. We therefore show no made-up performance rating: only price, context and features count towards its score.

Features, privacy and local use

• It supports tool calling, so it can drive an AI agent, call APIs or MCP servers.
• It can answer in an enforced JSON format (structured outputs).
• It is a reasoning model: it "thinks" before answering, which helps on hard tasks but uses more output tokens.

Its weights are not published: it can only be used through the Z.ai (Zhipu) API or a broker such as OpenRouter, which means sending your data off your machines.

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