Z.ai (Zhipu) · language model
GLM 5.3 Prime: pricing, context and benchmarks
GLM 5.3 Prime is a language model from Z.ai (Zhipu) released on September 23, 2026. It costs $2.8 per million input tokens and $8.8 per million output tokens, with a 1M-token context window. No independent score has been published for it so far.
| Price | 5/30 | |
|---|---|---|
| Context | 12/15 | |
| Features | 11/15 |
What you need to know about GLM 5.3 Prime
GLM 5.3 Prime was released by Z.ai (Zhipu) (China) on September 23, 2026. It accepts text as input and produces text. Its context window reaches 1,000,000 tokens, larger than 77 % 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 Prime pricing
On OpenRouter, GLM 5.3 Prime costs $2.8 per million input tokens and $8.8 per million output tokens. Counting three tokens read for every token written, its average price is $4.3 per million, more expensive than 84 % of paid models (5.6 times 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 $0.01. At 1,000 tasks a day, budget $300 a month. The price calculator redoes this with your own volumes.
Tokens already sent and cached are billed at $0.56 per million.
Performance and benchmarks
Epoch AI does not yet publish a capabilities index for GLM 5.3 Prime. 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.
Other Z.ai (Zhipu) models
| Model | Released | Avg. price | ECI |
|---|---|---|---|
| GLM 5.3 FlashX | Sep 18, 2026 | $0.59 | — |
| GLM 5.3 Flash | Aug 26, 2026 | $0.24 | 153.1 |
| GLM 5.3 | Aug 18, 2026 | $0.41 | 156 |
| GLM 5.2 | Jun 16, 2026 | $1.78 | 151.9 |
| GLM 5.1 | Apr 7, 2026 | $2.15 | 149.8 |
| GLM 5V Turbo | Apr 1, 2026 | $1.9 | — |
| GLM 5 Turbo | Mar 15, 2026 | $1.9 | — |
| GLM 5 | Feb 11, 2026 | $1.55 | 145.8 |
Verdict
GLM 5.3 Prime scores 47/100 on our grid, which only uses published figures.
Strengths
- Very large context (1M tokens): long documents or a whole codebase fit in one request.
- Agent-ready: tool calling and structured JSON output.
Limitations
- Expensive: costlier than 84 % of paid models.
- No independent score published: performance cannot be verified.
- Text only: reads neither images nor files.
Avoid if…
- you process large volumes on a tight budget;
- your data must not leave your servers;
- your tasks are mostly simple: a non-reasoning model will cost less.
Alternatives
Comparisons and tools
Learn more
Frequently asked questions
How much does GLM 5.3 Prime cost?
$2.8 per million input tokens and $8.8 per million output tokens on OpenRouter (checked October 25, 2026). A task with 2,000 tokens read and 500 written costs $0.01.
How big is GLM 5.3 Prime's context window?
1,000,000 tokens, roughly 750,000 words, with a maximum of 131,072 output tokens.
Can GLM 5.3 Prime run locally?
No, Z.ai (Zhipu) does not publish its weights: it is API-only.
Is GLM 5.3 Prime suitable for an AI agent?
Technically yes: it supports tool calling and structured outputs. Then check its cost for your volume.
What are the alternatives to GLM 5.3 Prime?
The closest models on price and performance are Claude Sonnet 5.5, Claude Sonnet 5, and GPT-4.1.
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Neutrality. No affiliate links. No vendor pays to be reviewed, rated or ranked. Reviews are directed by François Chollet, neutral and factual, and every data point is dated and sourced. How we score