erin.codes

Kubernetes is like buying a semi truck to pick up groceries & then being surprised you need a special license, a mechanic who knows semis, & a place to park the thing Every one of those problems is real & Kubernetes has really good answers for all of them, but you didn’t have any of them when you were driving a Honda For most apps the Honda is one server or something like Vercel or Railway where you push your code & it just runs The semi starts making sense when you’re actually hauling freight, like dozens of services, huge traffic spikes, & a team big enough that someone can own the truck full time Until then you’re paying a full-time mechanic to maintain something that drives to Trader Joe’s once a week Tell me the most overengineered setup you’ve seen for an app with 12 users 👇 #kubernetes #devops #softwareengineering #systemdesign #devlife

debugging but make it cute proof you can be kind, calm, and still commit to main

ngl standing can be pretty exhausting if you’re not used to it I find that stretching helps me stay on my feet for more hours everyday Building up my stamina and my code one day at a time The app is called Desk Yoga and it’s live on the App Store! #standingdesk #deskstretches #desksetup #deskstretch #codingjourney

If only it were that easy rm stands for remove. it deletes files and folders. the -r flag means recursive, which tells it to delete folders and everything inside them. the -f flag means force, which tells it not to ask for confirmation and not to complain about permissions. so when you combine them: rm -rf you are basically telling the system to delete something and everything inside it, immediately, without asking questions. normally, you would use it like: rm -rf folder_name to delete a directory and all its contents. it is powerful, but also dangerous, which is why developers are careful with it. a small mistake in the path can delete the wrong thing very quickly. in real systems though, there is no “undo” button. once files are removed this way, they are typically gone unless you have backups or special recovery tools. that is why you will often hear developers say you should always double check before running it, especially as a beginner. quick vocab ⭐️ rm means remove and is used to delete files or folders. -r means recursive and applies the command to folders and everything inside them. -f means force and skips confirmation prompts directory is another word for folder recursive means the command repeats through all nested files and folders inside a directory

Someone on here said that Pilates and Running for Gen Z is equivalent to Zumba for Gen X, Yoga & CrossFit to millennials, Jazzercise to baby boomers and now I can’t unsee it

How do you invalidate all active sessions when a user clicks “Log out of all devices”? This depends on the authentication method your system uses. ⸻ 1️⃣ Session-based authentication (server sessions) How it works: • When a user logs in, the server creates a session. • The session ID is stored on the server (DB/Redis). • The browser only stores the session ID in a cookie. Logout from all devices: The server simply deletes all sessions for that user from the session store. Result: Any request from any device → session lookup fails → user is logged out. This approach is straightforward because the server controls the session state. ⸻ 2️⃣ JWT-based authentication (token-based) How it works: • On login, the server issues an access token (JWT) and often a refresh token. • The client stores these tokens. • JWTs are stateless, meaning they are not stored on the server. Because of this, you cannot directly delete a JWT. To log out from all devices, systems typically use one of these strategies: Option A — Revoke refresh tokens (most common) • Store refresh tokens in DB/Redis. • On “log out all devices,” delete all refresh tokens for that user. • Access tokens expire soon → user must log in again everywhere. Option B — Version or timestamp check • Store a tokenVersion or logoutAllAt timestamp in the database. • When validating a JWT, compare it with the stored value. • If the token was issued before logoutAllAt (or has an old version) → reject it. ⸻ Interview answer: “In session-based authentication, logging out of all devices is simple because the server stores session state. We can invalidate all sessions by deleting them from the session store, such as Redis or a database. With JWT-based authentication, tokens are stateless, so they cannot be revoked directly. Instead, systems typically revoke refresh tokens stored in a database or implement a token version or timestamp check in the user record. When a user logs out from all devices, the server updates that value so any previously issued tokens become invalid.” #token #security #systemdesign #interview #tech [Jwt, sessions, authentication,