GLM 5.3 Flash vs Grok 4.3: price, context window and capabilities
GLM 5.3 Flash (z-ai/glm-5.3-flash) from Z.ai and Grok 4.3 (x-ai/grok-4.3) from SpaceXAI are both multimodal language models on the OceanToken API. GLM 5.3 Flash costs less per token than Grok 4.3: $0.15 against $1.25 per 1M input tokens (88% less) and $0.50 against $2.50 per 1M output tokens (80% less). GLM 5.3 Flash has the larger context window: 1.05M tokens (1,048,576) against 1M (1,000,000) for Grok 4.3. Both support tool calling, reasoning, structured outputs and image input; only GLM 5.3 Flash also lists video input; only Grok 4.3 also lists file input.
Side by side
| Spec | GLM 5.3 Flash | Grok 4.3 |
|---|---|---|
| Model | GLM 5.3 Flashz- | Grok 4.3x- |
| Publisher | Z.ai | SpaceXAI |
| Kind | Text, vision & video | Text & vision |
| Context window | 1.05M tokens1,048,576 | 1M tokens1,000,000 |
| Input price | $0.15 / 1M tokens | $1.25 / 1M tokens |
| Output price | $0.50 / 1M tokens | $2.50 / 1M tokens |
| Cached input price | $0.03 / 1M tokens | $0.20 / 1M tokens |
| Web search price | – | $0.005 / search |
| Inputs | text, images and video | text, images and files |
| Outputs | text | text |
| Tool calling | Yes | Yes |
| Reasoning | Yes | Yes |
| Structured outputs | Yes | Yes |
About these prices
Which should you choose?
- Choose GLM 5.3 Flash to spend less per token: 88% less for input and 80% less for output than Grok 4.3.
- Choose GLM 5.3 Flash for the longest inputs: its context window holds 1.05M tokens against 1M for Grok 4.3.
- Choose GLM 5.3 Flash if you need video input: Grok 4.3 does not list it.
- Not sure? Call both with the same OceanToken API key and compare them on your own prompts; each request is billed per use from one prepaid balance.
Get API Key GLM 5.3 Flash Grok 4.3
Frequently asked questions
Which is cheaper, GLM 5.3 Flash or Grok 4.3?
GLM 5.3 Flash. GLM 5.3 Flash costs less per token than Grok 4.3: $0.15 against $1.25 per 1M input tokens (88% less) and $0.50 against $2.50 per 1M output tokens (80% less). These are OceanToken starting prices per use; the OceanToken console always shows the current price.
Which has the larger context window, GLM 5.3 Flash or Grok 4.3?
GLM 5.3 Flash. GLM 5.3 Flash has the larger context window: 1.05M tokens (1,048,576) against 1M (1,000,000) for Grok 4.3.
Can I call both GLM 5.3 Flash and Grok 4.3 with one API key?
Yes. Both are on the OceanToken API at https://api.oceantoken.ai/v1: one API key and one prepaid balance call either model. Send the model id z-ai/glm-5.3-flash or x-ai/grok-4.3.
Models and publishers
GLM 5.3 Flash · Grok 4.3 · All Z.ai models · All SpaceXAI models
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