Diya

day 4 of building in public. yesterday I said postgres is my job queue. people always push back on this. let me explain 👇 most devs reach for redis or a queue service the moment they need background jobs. I get it. queues feel like a queue problem. but there's a SQL trick called FOR UPDATE SKIP LOCKED. it lets multiple workers pull jobs from a plain table without ever stepping on each other. worker 1 grabs row A → locked. worker 2 skips it, grabs row B → locked. no duplicates. no collisions. no extra service. one table. one trick. that's the queue. no redis to manage. no kafka to configure. no queue dashboard to monitor. just postgres which I already had. the best infrastructure decision is usually the one that removes a service, not adds one. 🧱

@tanujDE3180 bloom filter for the fast no. sharded database for the confirmed yes. debounce on the frontend so you're not checking every keystroke. three decisions that together make it feel instant

System Design Interview: You type a username in Gmail. Before you even finish typing, it says: “That username is taken.” There are billions of existing accounts. How does Google check availability in milliseconds?

@SumitM_X input is 98% of the cost here. the output is already optimized by being tiny.

A prompt costs: Input: 1000 tokens Output: 20 tokens Where would you optimize first?

@code_bytein if your API can return 1M rows your API is the bug

Most backend devs fail this in interviews. 1M users in DB. Client wants /users API. I've seen 200+ candidates answer this wrong. What's your answer? 👇

things nobody tells you before you ship your first product: - your first 10 users will be friends who never use it - you'll rewrite the landing page 6 times - the feature you spent 3 weeks on? nobody asks for it - the bug you ignored? that's what users find first save this for when you're feeling too confident

@omarvvvr typescript. Its just javascript that tells you about your bugs before users do.

Can you name a programming language better than JavaScript or not ?

@yourclouddude AI writes the code, i decide if its the right code, those are very different jobs.

You’re in a Python interview and they ask you: “Why should we hire you when AI can write Python scripts in seconds?” What’s your answer?

@Sarthak4Alpha cookie stores stuff. session lives on the server. token identifies you. JWT is a token with claims baked in. OAuth2 is the dance you do to get one from google

Interviewer: Tell me the difference between • Token • Session • Cookie • JWT • OAuth2

@EOEboh OPTIONS. the http method that exists purely so you can ask "what can i do here"

Scenario: You're integrating a third party API Before making a PUT request; how do you confirm the endpoint even supports PUT without actually making the call and potentially modifying data?

@EOEboh HEAD request. same as GET but returns only headers. content length tells you the size, zero bytes of body transferred

A user wants to download a 2GB file from your server. Before downloading, your app needs to show them the file size. How do you get that information without transferring the file itself?

@ishanxtwt "in memory" is where reads happen. disk is where survival happens

Interviewer: If Redis stores data in memory, then how does it prevent data loss after a restart?

@1Umairshaikh because claude rate limits you at 2pm and codex doesnt

Why do people use Codex when Claude exist Seriously Whyyyy????

@justbyte_ the tool that launched 4 days ago. always

Remember when everyone was talking about: - Perplexity - DeepSeek - Cursor - Sora - Midjourney - Runway - Llama - Copilot They dominated every discussion. What's everyone obsessed with now?

day 4 of building in public. yesterday I said postgres is my job queue. people always push back on this. let me explain 👇 most devs reach for redis or a queue service the moment they need background jobs. I get it. queues feel like a queue problem. but there's a SQL trick called FOR UPDATE SKIP LOCKED. it lets multiple workers pull jobs from a plain table without ever stepping on each other. worker 1 grabs row A → locked. worker 2 skips it, grabs row B → locked. no duplicates. no collisions. no extra service. one table. one trick. that's the queue. no redis to manage. no kafka to configure. no queue dashboard to monitor. just postgres which I already had. the best infrastructure decision is usually the one that removes a service, not adds one. 🧱

@Saanvi_dhillon 5173 😆

As a dev, what's your favorite localhost port?

@ayesha_fatiima instagram served a billion users on python. your todo app will be fine

Netflix uses Python Google uses Python Anthropic uses Python Meta uses Python xAI uses Python Perplexity uses Python DeepSeek uses Python Instagram uses Python Spotify uses Python Dropbox uses Python Reddit uses Python Pinterest uses Python Uber uses Python Airbnb uses Python Quora uses Python But sure… Python is ‘too slow’ for your todo app.

@sflorimm obviously cool. thats why nobody is paying

vibe coders, be honest: are you building something people need or something you thought was cool?

@TTrimoreau npm install already takes 30 seconds. you just want to monetize the suffering

Startup idea: Ads in terminal Imagine watching an unskipabble 30 seconds ad for running npm install.

@jahirsheikh8 you didnt delete anything. you marked it deleted. the cloud provider has snapshots, the replicas have copies, and the disk still has the bytes. delete is a UI lie

Senior backend interview questions: You delete the data. You delete the backups. You delete the logs. A court demands the records. Yet they somehow recover them. How?

@araseb_ stop being polite and tell me my idea is bad

What’s one feature you wish every AI had?