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Framework Security

Is FastAPI Secure? Security Features, Risks, and Hardening

Yes, FastAPI is generally secure when configured correctly. Here is what you need to know about its built-in protections, common vulnerabilities, and how to harden it for production.

Built-in Security Features

Automatic request validation via Pydantic models
Built-in OAuth2 and JWT security utilities
OpenAPI documentation auto-generates secure API specs
Dependency injection system for clean auth patterns
Automatic serialization prevents leaking internal fields

Common Vulnerabilities

Mass assignment if Pydantic models expose too many fields
SSRF through user-controlled URLs in async HTTP calls
Insecure default CORS configuration allowing all origins
Missing rate limiting (not included by default)
Exposed /docs and /redoc endpoints in production

Hardening Checklist

1Use separate Pydantic models for input, output, and database schemas
2Configure CORSMiddleware with specific origins, not wildcard
3Disable /docs and /redoc in production or protect with auth
4Implement dependency-based authentication on all protected routes
5Add slowapi or custom middleware for rate limiting
6Use HTTPS and configure trusted proxies correctly
7Validate and sanitize path parameters and query strings
8Set response_model to control exactly which fields are returned
9Use python-jose with RS256 for JWT token handling

Read the complete FastAPI security guide

In-depth blog post with code examples and best practices

Official FastAPI security documentation

Frequently Asked Questions

Is FastAPI secure?

Yes, FastAPI is generally secure when configured correctly. It includes built-in protections like automatic request validation via pydantic models. However, common misconfigurations and development patterns can introduce vulnerabilities.

What are the main security risks with FastAPI?

The most common FastAPI security risks include mass assignment if pydantic models expose too many fields, ssrf through user-controlled urls in async http calls, insecure default cors configuration allowing all origins.

How do I harden FastAPI for production?

Key hardening steps: Use separate Pydantic models for input, output, and database schemas. Configure CORSMiddleware with specific origins, not wildcard. Disable /docs and /redoc in production or protect with auth. Run a security check on your domain to identify specific issues.

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