# Limitations

* Only one `engine` instance can be active per API key. Please kindly apply your best effort to completely destroy created engines and associated processes from existence after use. 
* Hosting multiple models simultaneously requires separate API keys for each model - take a look at [Stable Diffusion](https://docs.everinfer.ai/examples/stable-diffusion-decouple-gpu-ops-from-code) demo to see how it is done.
* Interrupting Jupyter Notebook kernel does not guarantee `engine` destruction. Please restart the kernel before initializing new `engine`. 
* Max file size for [each ONNX stage](https://docs.everinfer.ai/model-management#model-chaining) is 2GB. Uploading models with external weight data will be possible soon. 
* Max `engine` input and output sizes should be 3GB (although it appears to be coded that way, we did not try anything truly gargantuous so far). 
* Prediction will time out after 1 minute. Common timeout causes: wrong input types, serialization issues. Please check your inputs.