This document outlines the security measures implemented in the Nexa ToolKit backend to protect user data and ensure service reliability.

• Secrets Management: All sensitive information, including Stripe API keys and webhook secrets, is managed via environment variables and is never hardcoded. We provide a .env.example file for local development.

• Input Validation: The FastAPI framework provides automatic data validation for all incoming request bodies based on Pydantic models. This prevents common data-based vulnerabilities.

• Rate Limiting: To prevent abuse and DoS attacks, API endpoints are rate-limited using slowapi. This applies to computationally intensive or sensitive endpoints like checkout creation and webhook processing.

• CORS: Cross-Origin Resource Sharing (CORS) middleware is configured to restrict access. In a production environment, this should be locked down to the specific domain of the frontend application.

• Error Handling: A global exception handler is in place to catch all unhandled errors. It prevents leaking sensitive stack traces or configuration details to the client, returning a generic 500 error instead.

• Dependency Management: Dependencies are managed via requirements.txt. It is recommended to use tools like pip-audit or GitHub's Dependabot to regularly scan for vulnerabilities in dependencies.

• HTTPS: The application is designed to be deployed behind a reverse proxy (like Nginx or Traefik) that terminates SSL/TLS, ensuring all traffic is encrypted via HTTPS.

• Stripe Webhook Verification: All incoming webhooks from Stripe are verified using the signature provided in the Stripe-Signature header to ensure they originate from Stripe and have not been tampered with.

If you discover a security vulnerability, please report it to us at security@example.com. We appreciate your efforts to disclose your findings responsibly.