GLM-5.3 vs Claude Sonnet 5.5: API Price for Everyday Coding Work
By Nicho
Z.ai describes GLM-5.3 as its flagship GLM model for complex software engineering and agentic work. Anthropic describes Claude Sonnet 5.5 as the best combination of speed and intelligence in its lineup, for well-scoped everyday tasks such as fixing bugs and creating documents. Many teams use either one as the default model behind a coding assistant.
This post compares published prices checked on 27 October 2026. It does not include benchmark results. Run your own evaluation before you switch.
Prices per million tokens
| Model and route | Input / 1M | Cache read / 1M | Output / 1M |
|---|---|---|---|
| Claude Sonnet 5.5, Anthropic API | $2.00 | $0.10 | $10.00 |
| GLM-5.3, Z.ai list price | $1.40 | $0.26 | $4.40 |
| GLM-5.3, cheapaimodel | $0.976972 | $0.181438 | $3.070483 |
Through cheapaimodel, GLM-5.3 input costs about 51% less than Sonnet 5.5, and output costs about 69% less. Output is where coding agents spend most of their money, so the output gap matters more.
Cache reads are the exception. Sonnet 5.5 charges $0.10 per million cached tokens, below GLM-5.3's $0.181438.
What a workload costs
| Workload | GLM-5.3 on cheapaimodel | Claude Sonnet 5.5 |
|---|---|---|
| 1M input + 0.2M output | $1.5911 | $4.0000 |
| 20M input + 4M output | $31.8214 | $80.0000 |
| 4M input + 16M cache reads + 2M output | $12.9519 | $29.6000 |
Even in the cache-heavy scenario, GLM-5.3 costs less than half as much, because output dominates the bill. Anthropic also charges for cache writes ($2.50 per million tokens on Sonnet 5.5 for a 5-minute cache), which the table leaves out. Anthropic's Batch API is 50% off; cheapaimodel does not offer a batch API.
Limits and inputs
| GLM-5.3 | Claude Sonnet 5.5 | |
|---|---|---|
| Context window | 1M tokens | 1M tokens |
| Max output | 128K tokens | 128K tokens |
| Input types | Text only | Text, image |
| Weights | Open, under the GLM-5.3 License | Closed |
GLM-5.3 currently accepts text input only. If your agent reads screenshots or diagrams, look at GLM-5.3-Flash, which takes text, image, video and file input, or keep Sonnet 5.5 for those steps.
The GLM-5.3 License is based on MIT. It adds a security-review condition for model-as-a-service businesses with more than $10 billion in revenue over 12 months, which matters only if you host the weights yourself at that scale.
When to choose which
Choose GLM-5.3 when:
- Your workload is text in, text out, such as code generation, refactoring and agent loops.
- Output tokens drive your bill and you want to cut it by more than half.
- You want the option to self-host the same open weights later.
Choose Claude Sonnet 5.5 when:
- Your prompts include images.
- Your own evaluations show a quality gap that is worth the price.
- You rely on Anthropic-specific features, such as its server tools or batch processing.
Try GLM-5.3
GLM-5.3 works with any OpenAI SDK. Set the base URL to https://api.cheapaimodel.ai/v1 and the model to glm-5.3. See the quickstart, the GLM-5.3 model page for live prices, or all open-source models.
Sources: Anthropic pricing, Anthropic models overview, GLM-5.3 guide, GLM-5.3 weights.