Looking at your logs, the issue is that your Python dependencies (including uvicorn) aren’t being installed during the build process. In your successful build, you can see the line “Installing required dependencies from requirements.txt…” but this is missing in the failed build.

This suggests a few potential issues:

1. Missing requirements.txt: Make sure you have a requirements.txt file in your project root that includes uvicorn and other dependencies.

2. Build command configuration: For Python/FastAPI projects on Vercel, you typically don’t need to specify the uvicorn command as your build command. Instead, you should:

   • Remove the custom build command
   • Let Vercel auto-detect your Python project
   • Create an api/ directory structure if you haven’t already

3. Project structure: Vercel expects Python APIs to be in the api/ directory. Your FastAPI app should be structured like:

   api/ ├── main.py # or index.py └── requirements.txt

Try these steps:

1. Ensure your requirements.txt includes uvicorn and fastapi
2. Move your FastAPI code to the api/ directory
3. Remove any custom build commands and let Vercel handle the deployment automatically

Resources:

• Vercel Python Runtime Documentation
• Deploying FastAPI to Vercel

removing the Build command fixes this issue! Is there anything changes recently regarding how you deploy python? i used the exact same config before but it only start to fail since 3 days ago.

I'm glad that worked for you!

What errors are you seeing now?

Hey! We're running this session next week after our recent announcement of Gel joining the team. Because you had posted about Python, I thought I'd give you a heads up in case you wanted to join us! :D

https://community.vercel.com/t/community-session-vercel-python/29118

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