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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/jaimegayo/KERNDOCUMENTATION/llms.txt

Use this file to discover all available pages before exploring further.

The KERN API is a FastAPI application deployed to Vercel using the @vercel/python runtime. All HTTP traffic is routed through a single entry point at api/index.py. The database tables are created automatically on first startup, so you don’t need to run migrations manually.

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Prerequisites

  • A Vercel account
  • A Neon PostgreSQL project
  • The KERN API repository forked or cloned

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Configuration files

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vercel.json

Vercel uses this file to know how to build and route requests:
vercel.json
{
  "builds": [
    {
      "src": "api/index.py",
      "use": "@vercel/python"
    }
  ],
  "routes": [
    {
      "src": "/(.*)",
      "dest": "api/index.py"
    }
  ]
}
Every request — regardless of path — is forwarded to api/index.py, which mounts the FastAPI application.

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requirements.txt

Vercel installs these dependencies before each deployment:
requirements.txt
fastapi
uvicorn[standard]
python-jose[cryptography]
pydantic
python-multipart
python-dotenv
sqlalchemy[asyncio]
asyncpg
psycopg2-binary

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Environment variables

Set these in your Vercel project’s Settings → Environment Variables panel before deploying.
VariableDescription
DATABASE_URLPostgreSQL connection string from Neon
SECRET_KEYSecret used to sign JWT tokens
DATABASE_URL format: 
postgresql+asyncpg://user:password@host/dbname
Neon provides this string in their dashboard under Connection Details. Use the asyncpg driver format shown above — the API strips any ?sslmode=require suffix and manages SSL via the connection arguments directly.
Never commit SECRET_KEY or DATABASE_URL to source control. Keep them in Vercel’s environment variable settings or a local .env file that is listed in .gitignore.

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Database tables

The API calls create_db_and_tables_sync() on startup. This function uses SQLAlchemy to inspect the database and create any missing tables:
TablePurpose
usersUser accounts, credentials, and profile data
routinesTraining plans created by or assigned to users
routine_exercisesIndividual exercises and sets within each routine
workout_sessionsCompleted workout history (volume, duration, steps)
If the tables already exist, startup is a no-op — the function uses checkfirst=True.

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Deployment steps

1

Fork or clone the repository

Fork the KERN API repository to your GitHub account, then connect it to a new Vercel project via the Vercel dashboard or the vercel CLI.
2

Create a Neon database

Sign in to Neon, create a new project, and copy the connection string from Connection Details. Make sure to select the asyncpg (async Python) format if available, or start with the standard postgresql:// string and replace postgresql:// with postgresql+asyncpg://.
3

Set environment variables in Vercel

In your Vercel project, go to Settings → Environment Variables and add:
  • DATABASE_URL — your Neon connection string
  • SECRET_KEY — a long, random string (use a password generator)
Apply the variables to Production, Preview, and Development environments as appropriate.
4

Deploy

Push a commit to your main branch, or trigger a manual deployment from the Vercel dashboard. Vercel will install dependencies from requirements.txt, build the project, and start the serverless function.On the first request after deployment, the API will create the database tables and log [INFO] Tablas de base de datos listas y verificadas.

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Verifying the deployment

Once deployed, visit /docs on your Vercel URL to access the FastAPI auto-generated Swagger UI. You can test every endpoint interactively without writing any code. 
https://your-kern-api.vercel.app/docs
You can also hit the root endpoint to confirm the API is online: 
curl https://your-kern-api.vercel.app/

{
  "message": "Bienvenido a Kern API",
  "version": "1.0.0",
  "docs": "/docs"
}

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