10 File Uploads Crashed Our Server — FastAPI File Uploads & Forms

A 10 MB upload read entirely into memory took the API down: `await file.read()` with no size limit grew memory linearly with every file, and 10 concurrent uploads triggered an OOM kill. Here's how to handle uploads safely — UploadFile streaming, mixing form fields, validation beyond Content-Type, filename sanitizing, and size caps. ⏳ Timestamps: 0:00 - Cold open: Memory usage grew linearly with file size; pod OOMKilled 0:15 - Intro 0:22 - FastAPI File Uploads & Forms 0:37 - What Is File Uploads & Forms? 0:54 - How FastAPI Handles Uploads 1:12 - Single File Upload with Validation 1:38 - Mixing Form Fields with Files 2:01 - Multiple File Uploads 2:30 - Validating File Type Beyond Content-Type 2:55 - Sanitising Filenames 3:26 - What Is Form Data? 3:56 - Optional File Uploads 4:21 - Persisting Uploaded Files 4:49 - Facts About FastAPI 5:18 - Authentication for Uploads 5:46 - Memory usage grew linearly with file size; pod OOMKilled 6:04 - The Fix 6:33 - Gotcha: Trusting Content-Type 6:46 - Gotcha: Path Traversal 6:59 - python-multipart Version Caveat 7:36 - Production Pitfall: Temporary File Cleanup 8:11 - Interview Questions 8:20 - FAQ 8:25 - Key Takeaways 8:36 - Next up 8:48 - Wrap-up 👉 Full article + code: https://thecodeforge.io/python/fastap... ⏭ Next up: FastAPI Middleware #FastAPI #Python