AI Smarties – Backend (Python + FastAPI)

The backend provides a WebSocket-based audio stream and real-time speech recognition using Google Speech-to-Text.

Setup and Running

1. Clone repo and navigate to directory

git clone git@github.com:AI-Smarties/back.git

cd back

2. Switch to development branch (dev)

git switch dev

3. Create and activate virtual environment

Mac / Linux

python3 -m venv venv
source venv/bin/activate

Windows

python -m venv venv
.\venv\Scripts\activate

4. Install dependencies

pip install -r requirements.txt

5. Set up PostgreSQL Database

The application uses PostgreSQL.

Docker Compose

docker compose up -d

or

docker-compose up -d

This starts a PostgreSQL container with the correct configuration. You can access the database at localhost:5432.

The application will automatically connect to localhost when running locally (environment variables are not required for local development).

6. Google Cloud Authentication (ADC)

The backend uses Google Cloud Speech-to-Text and the Application Default Credentials (ADC) method.

STEP 1: Browser Setup (Google Cloud Console)

Do these first in your web browser:

1. Create a Project: Go to Google Cloud Console, create a new project, and copy the Project ID (e.g., smarties-backend-v2).

2. Activate Free Trial: Click the "Activate" banner at the top of the page to claim your free credits.

3. Enable the API: Search for "Cloud Speech-to-Text API" in the top search bar and click Enable.

STEP 2: CLI Setup (Terminal)

Run these commands in your terminal:

1. Install GCloud CLI: Download and install here.

2. Enable the API: Search for "Cloud Speech-to-Text API" in the top search bar and click Enable.

   gcloud auth application-default login

3. Link to Project: Run this command (replace [PROJECT_ID] with the ID you copied in Step 1):

   gcloud auth application-default set-quota-project [PROJECT_ID]

7. Start the server

fastapi run src/main.py --host 0.0.0.0

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Daily development workflow

When you return to coding, activate the virtual environment and check for updates:

1. Start database: docker-compose up -d (if using Docker Compose)
2. Activate environment: source venv/bin/activate
3. Fetch latest changes: git pull origin dev
4. Start server: fastapi dev src/main.py

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Project structure

• src/main.py – FastAPI application and WebSocket endpoint
• src/asr.py – Streaming ASR (Google Speech-to-Text)
• src/db.py – Database connection configuration
• src/models.py – SQLAlchemy database models
• requirements.txt – Dependencies
• docker-compose.yaml – Local PostgreSQL setup
• manifests/ – Deployment configurations

Frontend integration

Backend is intended to be used with the Flutter frontend