Deploy your FastAPI app to Vercel
Step-by-step deployment help for FastAPI apps on Vercel. We fix FastAPI-specific deployment issues, configure Vercel, and get your app live. From $19.
FastAPI issues we fix before deploying
Common FastAPI problems that affect Vercel deployments.
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.
Vercel deployment issues we check for
Common Vercel problems that break FastAPI apps in production.
Serverless function size exceeds 50MB limit
AI tools bundle heavy dependencies into API routes without tree-shaking, pushing serverless functions past Vercel's 50MB compressed size limit and failing the build.
Edge runtime incompatible with Node.js APIs
Generated code uses fs, crypto, or other Node.js built-ins inside Edge Runtime routes, causing deployment failures since Edge only supports a subset of Web APIs.
ISR revalidation not triggering correctly
Incremental Static Regeneration configured with stale revalidate values or missing on-demand revalidation hooks, serving outdated content indefinitely.
Environment variables missing in production
Secrets added to .env.local but not configured in the Vercel dashboard, causing runtime crashes only in production while working perfectly in local dev.
Start with a self-serve audit
Get a professional review of your FastAPI project before deploying to Vercel.
External Security Scan
Black-box review of your public-facing app. No code access needed.
- OWASP Top 10 vulnerability check
- SSL/TLS configuration analysis
- Security header assessment
- Expert review within 24h
Code Audit
In-depth review of your source code for security, quality, and best practices.
- Security vulnerability analysis
- Code quality review
- Dependency audit
- Architecture review
- Expert + AI code analysis
Complete Bundle
Both scans in one package with cross-referenced findings.
- Everything in both products
- Cross-referenced findings
- Unified action plan
100% 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
How do I deploy a FastAPI app to Vercel?
We handle FastAPI deployments to Vercel end to end. Start with our code audit ($19) to identify deployment blockers specific to your FastAPI project, then we configure Vercel, fix issues, and get your app live in production.
What FastAPI issues affect Vercel deployments?
FastAPI projects commonly have blocking calls inside async endpoints and missing authentication on endpoints. On Vercel, these combine with serverless function size exceeds 50mb limit and edge runtime incompatible with node.js apis to cause deployment failures.
Can SpringCode deploy my FastAPI project to Vercel?
Yes. We specialize in deploying FastAPI applications to Vercel. We audit your codebase for FastAPI-specific issues, configure Vercel correctly, and handle the full deployment so your app runs reliably in production.
What does FastAPI deployment to Vercel cost?
Our code audit ($19) identifies all Vercel deployment blockers in your FastAPI project. Full deployment assistance is scoped with a fixed quote after the audit — no hourly billing or surprise charges.
Related resources
Other techs on Vercel
Deploy FastAPI elsewhere
Need help deploying FastAPI to Vercel?
Tell us about your project. We'll respond within 24 hours with a clear plan and fixed quote.