How WhatsApp Works Without Internet: Offline Messaging and Sync ExplainedSending a Message in Airplane Mode Imagine opening WhatsApp, typing a message and pressing send while your phone is in airplane mode. Surprisingly, the message immediately appears inside the conversatMay 31 · 7 min readunderstanding-app-dev.hashnode.dev
How Instagram Stores Reels, Photos, and Drafts Behind the ScenesFrom Recording a Reel to Watching It Again When you record a Reel on a social media application, a surprisingly large number of systems start working behind the scenes. To the user it feels simple: reMay 31 · 6 min readunderstanding-app-dev.hashnode.dev
Storing Uploaded Files and Serving Them in ExpressOnce file uploads start working in an Express application the next important step is understanding where those uploaded files actually go and how users can access them later. Many developers initiallyMay 10 · 5 min readunderstanding-web-dev.hashnode.dev
Handling File Uploads in Express with MulterFile uploads are extremely common in backend development because many applications need users to upload profile pictures PDFs documents videos or other media files. Initially file uploads feel slightlMay 10 · 4 min readunderstanding-web-dev.hashnode.dev
JWT Authentication in Node.js Explained SimplyAuthentication is one of the most important parts of backend development because servers need some way to identify users after login. Suppose a user logs into a website and then tries to open their daMay 10 · 6 min readunderstanding-web-dev.hashnode.dev
