FastAPI code review, security audit, and deployment services
FastAPI is the fastest-growing Python framework for APIs, and it's what most AI tools reach for when building backend services, especially AI wrappers and data pipelines. Cursor and Claude Code frequently generate FastAPI projects - but vibe coded FastAPI apps often mix async and sync code incorrectly, skip input validation, and ship without proper authentication.
Common FastAPI issues we find
Real problems from FastAPI codebases we've reviewed.
Blocking calls inside async endpoints
Synchronous database calls, file operations, or HTTP requests inside async def endpoints block the entire event loop, making your API unresponsive under load.
Missing authentication on endpoints
API routes that handle sensitive data or actions without any auth middleware - Depends() for authentication is simply not included in the route definition.
No CORS configuration
CORSMiddleware either missing (blocking all cross-origin requests) or set to allow_origins=['*'] (allowing any website to call your API).
Pydantic models without validation constraints
Request models that accept any string length, any number range, and any format. No Field() constraints, so invalid data flows through your system.
Uvicorn dev server in production
Running uvicorn with --reload flag in production, or using a single worker. This means one crash or slow request brings down the whole API.
Missing error handling middleware
Unhandled exceptions return raw 500 errors with stack traces to clients, leaking internal code structure and potentially sensitive information.
No rate limiting on public endpoints
Public API endpoints (especially AI wrapper endpoints that call OpenAI or similar) have no rate limiting, so a single user can run up massive costs.
Database connections not pooled
Creating a new database connection on every request instead of using a connection pool, causing connection exhaustion under load.
FastAPI production checklist
Key checks before deploying your FastAPI app.
Async endpoints only call async functions (no blocking I/O)
Authentication dependency on all protected routes
CORS configured for specific origins (not wildcard)
Pydantic models have Field() validation constraints
Uvicorn running with multiple workers behind a process manager
Global exception handler returns safe error responses
Rate limiting on public and expensive endpoints
Database connection pooling configured (SQLAlchemy or similar)
Health check endpoint for monitoring and load balancers
OpenAPI docs disabled or protected in production
Not sure if your app passes? Our code audit ($19) checks all of these and more.
Our FastAPI services
Security Review
Deep security analysis of your application - from API endpoints to database access.
Deploy & Ship
From local development to production deployment.
Performance
Identify and fix performance bottlenecks - slow page loads, laggy interactions, and expensive operations.
Infrastructure
Databases, APIs, auth systems, email, file storage - the backend services that power your application.
AI tools that generate FastAPI code
Start with a self-serve audit
Get a professional review of your FastAPI project at a fixed price.
Security Review
Automated Security Scan
AI-powered analysis of your codebase. Get a detailed report with prioritized findings within 24 hours.
Get StartedSecurity Review
Manual Security Review
Expert engineer works on your project directly. Fixed scope, fixed price, no surprises.
Get a QuoteSecurity Review
Full Pentest
Enterprise-grade engagement tailored to your needs. Dedicated engineer, ongoing support.
Fix Bugs
Code Audit
AI-powered analysis of your codebase. Get a detailed report with prioritized findings within 24 hours.
Get StartedFix Bugs
Bug Fixing
Expert engineer works on your project directly. Fixed scope, fixed price, no surprises.
Get a QuoteFix Bugs
Ongoing Support
Enterprise-grade engagement tailored to your needs. Dedicated engineer, ongoing support.
Refactor Code
Code Audit
AI-powered analysis of your codebase. Get a detailed report with prioritized findings within 24 hours.
Get StartedRefactor Code
Refactoring
Expert engineer works on your project directly. Fixed scope, fixed price, no surprises.
Get a QuoteRefactor Code
Full Rewrite
Enterprise-grade engagement tailored to your needs. Dedicated engineer, ongoing support.
100% of your audit purchase is credited toward any paid service. Start with an audit, then let us fix what we find.
How it works
Tell us about your app
Share your project details and what you need help with.
Expert + AI audit
A human expert assisted by AI reviews your code within 24 hours.
Launch with confidence
We fix what needs fixing and stick around to help.
Frequently asked questions
Is my AI-generated FastAPI backend production-ready?
Almost certainly not. AI tools get the basic routes right but miss async correctness, authentication, rate limiting, and production server configuration. We review and fix all of these before launch.
How do I deploy a FastAPI app properly?
We deploy FastAPI with Uvicorn behind Gunicorn with multiple workers, configure connection pooling, set up health checks, and add monitoring. We deploy to Railway, Render, AWS, or Docker-based platforms.
Can you add authentication to my FastAPI project?
Yes. We implement JWT or OAuth2 authentication with proper dependency injection, token refresh, role-based access control, and secure session handling.
Related resources
Need help with your FastAPI project?
Tell us about your project. We'll respond within 24 hours with a clear plan and fixed quote.