Compare / Models
GLM-5.3-Flash vs GPT-5.5
Price, context window and capabilities side by side — read from the same catalog that meters your calls, not from a press release.
GLM-5.3-Flash is 33x cheaper on input. GLM-5.3-Flash is 60x cheaper on output. GLM-5.3-Flash holds 1M tokens against 256K.
At a glance
Side by side
Z.ai
Native multimodal coding model at the lowest rate in the catalog.
Specifications
Every difference we can measure
| GLM-5.3-Flash | GPT-5.5 | |
|---|---|---|
| Input price | $0.15/M | $5/M |
| Output price | $0.5/M | $30/M |
| Context window | 1M tokens | 256K tokens |
| Vision | Yes | Yes |
| Tool calling | Yes | Yes |
| Prompt caching | Yes | No |
| Long context | Yes | No |
A row appears only when we hold the fact for both models. Anything the provider has not published is left out rather than guessed, so an empty row is missing data and never a zero.
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FAQ
Frequently asked questions
What is the difference between GLM-5.3-Flash and GPT-5.5?
GLM-5.3-Flash is 33x cheaper on input. GLM-5.3-Flash is 60x cheaper on output. GLM-5.3-Flash holds 1M tokens against 256K. Only GLM-5.3-Flash declares prompt caching. Only GLM-5.3-Flash declares long context. Both run on the same endpoint and the same key here, so trying each is a one-line change to the model id.
Which is cheaper, GLM-5.3-Flash or GPT-5.5?
GLM-5.3-Flash is, on input tokens. Output usually dominates the bill on generative work, so check the output row above against your own ratio of prompt to completion before deciding.
Can I switch between GLM-5.3-Flash and GPT-5.5 without changing my code?
Yes. Both are OpenAI-compatible through one CompanyFabric key, so switching is the model string and nothing else — no second SDK, no second contract, one prepaid balance across both.
Do I have to choose?
No. Send companyfabric/auto and we route each request to the cheapest model that can serve it, which is how most people use both without deciding in advance.
One key. Every model. Exact prices.
Run GLM-5.3-Flash and GPT-5.5 on the same key and compare them on your own prompts. Free starter credits included, no subscription required.