Host a .NET Blazor WebAssembly App on Amazon S3 and Amazon CloudFront

This article demonstrates how to host a .NET Blazor WebAssembly application on AWS using Amazon S3 and CloudFront with infrastructure-as-code via Terraform.

• Blazor WASM compiles to static files (HTML, CSS, JavaScript, WASM binaries) suitable for S3 storage and CloudFront distribution
• Use Origin Access Control (OAC) to securely restrict S3 bucket access to a specific CloudFront distribution via SigV4 signing
• Implement two cache policies: one-year immutable caching for content-hashed _framework/* files and zero-TTL for index.html to ensure fresh deployments
• Configure CloudFront custom error responses to rewrite 403/404 errors to index.html for proper SPA client-side routing and deep link support
• Deploy script handles correct MIME types and Content-Encoding headers for pre-compressed Brotli files, then invalidates CloudFront cache
• Optional custom domain support via ACM certificate and Route 53 DNS records

This serverless hosting approach eliminates compute costs, provides global low-latency access through 400+ edge locations, and requires no server management or patching.