# GLM-5.3

GLM-5.3 is a text generation model from Z.AI, available through the Impossibl API. Its published context window is 1,000,000 tokens. The advertised input rate is $1.40 per million input tokens. The advertised output rate is $4.40 per million output tokens.

- Model identifier: ` zai/glm-5.3 `
- Creator: Z.AI
- Model type: Text generation
- Canonical model page: [GLM-5.3](<https://impossibl.com/zai/glm-5.3>)
- API availability: Listed as serving through Impossibl.
- Creator release date: 2026-08-14

## Capabilities and limits

- Context window: 1,000,000 tokens
- Maximum output tokens: Not published in the public catalog; this is separate from the context window.
- Inputs: text
- Outputs: text
- Tool calling: Not published

## API access

Use ` zai/glm-5.3 ` as the model identifier through the Impossibl API.

Published API endpoints:

- ` /v1/chat/completions `

[API quickstart](<https://impossibl.com/docs/agent-quickstart>) · [Models and billing documentation](<https://impossibl.com/docs/models>)

## Published API prices

All rates are in USD. An unpublished rate is unknown, not zero. Workspace-specific pricing, taxes, balance-purchase fees, billing adjustments, and tool charges can affect the amount paid.

| Usage | Published base rate | Billing unit |
| --- | --- | --- |
| Input | $1.40 | per million input tokens |
| Output | $4.40 | per million output tokens |
| Cache read | $0.26 | per million cached input tokens |
| Cache write (default retention) | Not published | per million tokens |
| Cache write (one-hour retention) | Not published | per million tokens |
| Audio input | Not published | per million audio input tokens |

## Independent benchmarks

Source: [Artificial Analysis](<https://artificialanalysis.ai/>). Last checked: 2026-09-11T11:52:20.926Z.
Configurations are evaluated separately. API scores retain their original units. Unmeasured scores are omitted.

### GLM-5.3 (max)

Source: [Evaluation source](<https://artificialanalysis.ai/models/glm-5-3>)

| Benchmark | Score |
| --- | --- |
| Intelligence Index | 44.86 |
| Omniscience Index | 14.30 |
| GPQA | 91.72% |
| Humanity’s Last Exam | 42.26% |
| SciCode | 59.03% |
| CritPt | 19.14% |
| Terminal-Bench v2.1 | 83.90% |
| Terminal-Bench v4.0 | 41.92% |
| AA-LCR | 79.67% |
| Multilingual LCR | 48.33% |
| GDPval Elo | 1667.27 |
| GDP.pdf All-pass | 11.20% |
| AutomationBench Partial | 62.20% |
| Tau Banking | 50.31% |
| coding index (API) | 74.8 |
| agentic index (API) | 53.4 |
| intelligence index (API) | 44.9 |

Full benchmark data and breakdowns: [Complete benchmark snapshot](<https://api.impossibl.com/v1/models/zai/glm-5.3/benchmarks>).


## Availability and retirement

The model is listed as serving. No retirement is announced in the current public catalog.

## Frequently asked questions

### What is GLM-5.3?

GLM-5.3 is a text-generation model from Z.AI, available through the Impossibl API.

### How much does GLM-5.3 cost?

GLM-5.3 costs $1.40 per million input tokens and $4.40 per million output tokens through the Impossibl API. Cache reads cost $0.26 per million tokens. All rates are in USD.

### What is the context length of GLM-5.3?

GLM-5.3 has a 1,000,000-token context window through the Impossibl API.

### What inputs and outputs does GLM-5.3 support?

GLM-5.3 accepts text as input. GLM-5.3 returns text.

### How do I use GLM-5.3 through an API?

GLM-5.3 is available through the Impossibl API. Use zai/glm-5.3 as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request.

### When was GLM-5.3 released?

Z.AI released GLM-5.3 on August 14, 2026.

Sources: [Creator release announcement](<https://z.ai/blog/glm-5.3>)

## Sources and related links

Prices, limits, capabilities, endpoints, and availability come from the public Impossibl catalog. Creator documentation supplies descriptions and release dates where available; it does not override the published API offering.

- [Public Impossibl model catalog](<https://api.impossibl.com/v1/models>)
- [Full model directory as JSON](<https://impossibl.com/models.json>)
- [GLM-5.3: model details and pricing](<https://impossibl.com/zai/glm-5.3>)
- [Model directory](<https://impossibl.com/models>)