Every web framework tutorial shows you how to accept a file upload.

Almost none show you what to do next.

You validate the Content-Type header. You check the extension. You think you're done.

You're not.

The default file upload stack leaves you exposed on four fronts: parsing security, file type spoofing, size abuse, and malware. These 7 tools close each gap without requiring a dedicated security team.

TL;DR: File upload security requires a stack, not a single library. These 7 tools cover parsing, validation, and scanning end-to-end.

Table of Contents

1. 
   pompelmi — antivirus scanning before the file touches permanent storage


2. 
   multer — secure multipart parsing with built-in size and field limits


3. 
   busboy — low-level streaming parser for fine-grained upload control


4. 
   file-type — detect the real file type from magic bytes, not the filename


5. 
   mime-types — map MIME types reliably without trusting user input


6. 
   sharp — re-encode images to eliminate embedded payloads


7. 
   archiver — control archive creation to prevent zip bomb and path traversal risks

1) pompelmi — scan files before they land

What it is: A minimal Node.js wrapper around ClamAV that scans any uploaded file and returns a typed verdict — Clean, Malicious, or ScanError. Zero runtime dependencies, no cloud, no daemon required.

Why it matters: The file upload attack surface doesn't start with storage — it starts with what you accept. A PDF that passes as application/pdf can still carry a macro payload. An image can embed executable content. pompelmi adds a scanning layer before any file touches your database or object storage, running ClamAV locally so no user data ever leaves your server.

Best for: Express, Fastify, NestJS, Next.js, SvelteKit, any Node.js app that accepts user file uploads

Links:

Multer is a node.js middleware for handling multipart/form-data, which is primarily used for uploading files. It is written
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