How does a site like architectrender.com work on the backend?

I'm trying to understand how someone can run a specific ControlNet and Stable Diffusion model with scalable GPU resources. How would someone design a system to achieve this? I've messed around with models on Replicate, but none seem to do a good job with converting a doodle to a photorealistic image. I can do it perfectly fine in the Stable Diffusion web UI, but the API for that is only accessible locally. Anyone have any ideas or can guide me …

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