Is ComfyUI completely offline?

Why “offline” matters in generative AI

Many artists, researchers, and studios ask: can ComfyUI run completely offline? The question matters because privacy, reliability, and cost all depend on how software handles data.

At first glance, ComfyUI can be confusing. It opens in your web browser—leading some to think it’s an online tool. In reality, ComfyUI is a local-first app that happens to use your browser as its interface. That’s not the same thing as SaaS.

And with Promptus with ComfyUI, you can run:

• Desktop (offline): Total privacy and local speed.
• Cloud (online): Same ComfyUI graphs inside your browser on managed GPUs.

This hybrid gives you maximum flexibility—create offline when you want privacy, or switch to Cloud when you need collaboration or high VRAM.

ComfyUI at its core: local, anonymous, private

• Local-first application: ComfyUI spins up a local server (e.g., http://127.0.0.1:8188) and uses your browser as a front-end.
• Anonymous: The project does not require accounts or telemetry. When you run it offline, your prompts, models, and outputs stay entirely on your machine.
• Flexible engine: It orchestrates models like Stable Diffusion, SDXL, Flux, Wan 2.2, and many more.

👉 To learn more about the relationship between Stable Diffusion and ComfyUI, see our in-depth comparison at: Which is Better Stable Diffusion or ComfyUI? 

Promptus is the best way to run ComfyUI

You can install ComfyUI manually from GitHub—but that means wrangling CUDA drivers, Python versions, PyTorch builds, and community nodes that may or may not work.

Promptus with ComfyUI solves all of this:

• 1-click installer (official at Promptus.ai): No command-line headaches, just install and create.
• Optimized builds: Pre-tested, stable, and VRAM-efficient versions of ComfyUI.
• Bundled nodes: Curated set of proven nodes that just work.
• Auto-updates: Fixes and features without manual patching.
• Playground + ComfyUI: Run Stable Diffusion models quickly in the Playground, or dive into advanced workflows with ComfyUI graphs.
• Integrated models: Access Gemini Flash 2.5 Image (Nano Banana), Stable Diffusion/SDXL, Flux, Wan 2.2, and hundreds more.

Simply put: Promptus is the best version of ComfyUI—easier, faster, more stable.

How to run ComfyUI offline

Step 1: Install Promptus Desktop

Download from the official site: www.promptus.ai. It provisions ComfyUI with all dependencies.

Step 2: Download models & nodes

Grab SDXL Base/Refiner, LoRAs, ControlNet weights, and any custom nodes. Promptus makes managing these simple. You can upload the models direclty in PManager or inside the ComfyUI canvas.

Step 3: Disconnect

Once dependencies and models are local, you can go completely offline. Prompts, graphs, and generations stay private.

Step 4: Optional Cloud bursts

Need a 24GB GPU or want to share a graph in-browser? Upload to Promptus ComfyUI Cloud and keep working seamlessly.

Limitations of offline operation

• Updates require internet. To fetch new builds or nodes, you’ll need to reconnect.
• Cloud sessions are online. Anytime you use Promptus ComfyUI Cloud (or any provider), your session relies on the internet.
• Storage matters. Keep enough local SSD space (20–40GB+) for models and outputs.
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Hybrid is the winning setup

• Offline (Promptus Desktop): Private, secure, and free for subscribers (or $49 lifetime).
• Online (Promptus Cloud): Managed GPUs, easy collaboration, and browser access.

Together, they let you choose the right balance between privacy and convenience.

Privacy, anonymity, and control

• ComfyUI itself is anonymous—no accounts required.
• Promptus Desktop keeps everything local and offline.
• Cloud is optional and isolated for each session.

For agencies, enterprises, and creators who care about data security, this hybrid gives you the best of both worlds.

Conclusion

So, is ComfyUI completely offline?

Yes—once installed, ComfyUI runs 100% offline. No data leaves your computer. The only time you need the internet is to install updates or fetch new models.

And with Promptus with ComfyUI, you don’t just get offline privacy—you get the best packaged version of ComfyUI, with one-click installs, auto-updates, integrated models, and the ability to burst to Cloud when needed.

For artists, studios, and researchers who want control, privacy, and speed, Promptus is the official way to download and run ComfyUI.