Deploy your C# app to Fly.io
Step-by-step deployment help for C# apps on Fly.io. We fix C#-specific deployment issues, configure Fly.io, and get your app live. From $19.
C# issues we fix before deploying
Common C# problems that affect Fly.io deployments.
Async void methods
Using async void instead of async Task in non-event-handler methods, causing unhandled exceptions that crash the process silently.
Missing IDisposable implementation
Database connections, HTTP clients, and file streams not disposed properly, causing resource exhaustion under load.
Insecure deserialization
Using BinaryFormatter or Newtonsoft with TypeNameHandling.All to deserialize untrusted data, enabling remote code execution.
Missing authorization attributes
ASP.NET controller actions without [Authorize] or policy-based checks, exposing endpoints to unauthenticated users.
Fly.io deployment issues we check for
Common Fly.io problems that break C# apps in production.
Dockerfile missing or misconfigured
Fly.io requires a Dockerfile for deployment. AI tools that scaffold without one force flyctl to auto-generate a suboptimal Dockerfile that misses build steps.
Volume only available in a single region
Fly volumes are pinned to one region. Multi-region deployments try to access a volume that doesn't exist in other regions, causing crashes.
Machine restarts losing in-memory state
AI-generated apps store session data or caches in memory. Fly machines can restart or migrate, wiping all in-memory state without warning.
Internal DNS resolution failing between services
Services within a Fly organization communicate via <app>.internal hostnames, but AI-generated code hardcodes localhost or public URLs.
Start with a self-serve audit
Get a professional review of your C# project before deploying to Fly.io.
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 C# app to Fly.io?
We handle C# deployments to Fly.io end to end. Start with our code audit ($19) to identify deployment blockers specific to your C# project, then we configure Fly.io, fix issues, and get your app live in production.
What C# issues affect Fly.io deployments?
C# projects commonly have async void methods and missing idisposable implementation. On Fly.io, these combine with dockerfile missing or misconfigured and volume only available in a single region to cause deployment failures.
Can SpringCode deploy my C# project to Fly.io?
Yes. We specialize in deploying C# applications to Fly.io. We audit your codebase for C#-specific issues, configure Fly.io correctly, and handle the full deployment so your app runs reliably in production.
What does C# deployment to Fly.io cost?
Our code audit ($19) identifies all Fly.io deployment blockers in your C# project. Full deployment assistance is scoped with a fixed quote after the audit — no hourly billing or surprise charges.
Related resources
Need help deploying C# to Fly.io?
Tell us about your project. We'll respond within 24 hours with a clear plan and fixed quote.