GLM 5.3 FlashX vs Claude Sonnet 5.5: price, context window and capabilities
GLM 5.3 FlashX (z-ai/glm-5.3-flashx) from Z.ai and Claude Sonnet 5.5 (anthropic/claude-sonnet-5.5) from Anthropic are both multimodal language models on the OceanToken API. GLM 5.3 FlashX costs less per token than Claude Sonnet 5.5: $0.37 against $1.80 per 1M input tokens (79% less) and $1.25 against $9.00 per 1M output tokens (86% less). Claude Sonnet 5.5 is 10% off its official price on OceanToken, for every account. GLM 5.3 FlashX has the larger context window: 1.05M tokens (1,048,576) against 1M (1,000,000) for Claude Sonnet 5.5. Both support tool calling, reasoning and image input; only GLM 5.3 FlashX also lists video input; only Claude Sonnet 5.5 also lists structured outputs and file input.
Side by side
| Spec | GLM 5.3 FlashX | Claude Sonnet 5.5 −10% |
|---|---|---|
| Model | GLM 5.3 FlashXz- | Claude Sonnet 5.5anthropic/ |
| Publisher | Z.ai | Anthropic |
| Kind | Text, vision & video | Text & vision |
| Context window | 1.05M tokens1,048,576 | 1M tokens1,000,000 |
| Input price | $0.37 / 1M tokens | $1.80 / 1M tokens |
| Output price | $1.25 / 1M tokens | $9.00 / 1M tokens |
| Cached input price | $0.09 / 1M tokens | $0.10 / 1M tokens |
| Cache write price | – | $2.50 / 1M tokens |
| Web search price | – | $0.01 / search |
| Discount (vs official, top tier) | — | −10% |
| Inputs | text, images and video | text, images and files |
| Outputs | text | text |
| Tool calling | Yes | Yes |
| Reasoning | Yes | Yes |
| Structured outputs | Not listed | Yes |
About these prices
Which should you choose?
- Choose GLM 5.3 FlashX to spend less per token: 79% less for input and 86% less for output than Claude Sonnet 5.5.
- Choose GLM 5.3 FlashX for the longest inputs: its context window holds 1.05M tokens against 1M for Claude Sonnet 5.5.
- Choose GLM 5.3 FlashX if you need video input: Claude Sonnet 5.5 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 FlashX Claude Sonnet 5.5
Frequently asked questions
Which is cheaper, GLM 5.3 FlashX or Claude Sonnet 5.5?
GLM 5.3 FlashX. GLM 5.3 FlashX costs less per token than Claude Sonnet 5.5: $0.37 against $1.80 per 1M input tokens (79% less) and $1.25 against $9.00 per 1M output tokens (86% less). Claude Sonnet 5.5 is 10% off its official price on OceanToken, for every account. The OceanToken console always shows the current price.
Which has the larger context window, GLM 5.3 FlashX or Claude Sonnet 5.5?
GLM 5.3 FlashX. GLM 5.3 FlashX has the larger context window: 1.05M tokens (1,048,576) against 1M (1,000,000) for Claude Sonnet 5.5.
Can I call both GLM 5.3 FlashX and Claude Sonnet 5.5 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-flashx or anthropic/claude-sonnet-5.5.
Models and publishers
GLM 5.3 FlashX · Claude Sonnet 5.5 · All Z.ai models · All Anthropic models
More comparisons
Claude Sonnet 5.5 vs GPT-6 Sol · Claude Opus 5.5 vs Claude Sonnet 5.5 · Kimi K3 vs Claude Sonnet 5.5 · Grok 4.6 vs Claude Sonnet 5.5 · All comparisons