Adarsh Singh

🎉 Thrilled to make open-source contribution to @calcom ! 🚀💻 Huge thanks to @100xDevs and @kirat_tw for the guidance — this experience reinforced the power of building, shipping, and contributing to real-world products. #OpenSource #WebDev #BuildInPublic

Most engineers use authentication. Few truly understand it. 🤔 Today I deep-dived into how modern systems authenticate users 🔐 Learned: • Auth API structure (Next.js backend) • Frontend → backend → DB flow 🔄 • Session vs Token auth 🧠 • Access vs Refresh tokens 🎟️ • Expiry, validation, storage ⏳ 💡 Key insight: Modern systems use access + refresh tokens, not just one. Why it matters: • Better security 🔒 • Seamless UX 😊 • Scalable systems 📈 This changed how I think about auth completely. 🌍 #Backend #NodeJS #NextJS #SystemDesign

Here’s a Twitter/X short version (crisp + impactful): Underestimated by backend engineers: Switching 🚀 • Data takes multiple paths • Network auto-selects best route • Packet switching powers APIs In backend: Requests → packets → different routes → reassembled 👉 Same API ≠ same latency Why it matters: Debug beyond code #Backend #NodeJS #SystemDesign

Created MVP for a backed startup in the construction industry 🚀 Problem: Tender analysis manually is time-consuming, error-prone, and difficult to scale Solution: • Backend development with Node.js + REST API • Async processing pipeline of PDF documents • Created AI-enabled RAG for analysis and risks detection Outcome: -> Automated process of analyzing tenders saving lots of time Technical stack: Node.js • Next.js • TypeScript • MongoDB • APIs • AI Lessons learned: Quickly getting something done is good, but creating reliable and async architecture is key for scaling MVP released to the founder – time will tell 🤞 #Backend #NodeJS #AI #SoftwareEngineer #SaaS

Your API request doesn’t just hit a server… It hits the right process inside that server 🤯 Most backend devs ignore this: Port Numbers 🚀 ✅ Port = communication endpoint ✅ One machine → multiple processes ❌ Request ≠ just server ➡️ It must reach the correct port Example: localhost:3000 → IP finds server → Port finds your app 🎯 Why it matters: Without ports → chaos With ports → correct service responds #Backend #NodeJS #APIs #ComputerNetworking

MVP Update 🚀 Backend is DONE. Built: • PDF processing pipeline • RAG-based insights • Risk + gap detection • Scalable async workflows Next: Frontend by tomorrow → then reaching out to founders. Lesson: Shipping fast is good. Building systems that handle real data is better. #BuildingInPublic #AI #Backend 2/2

Your API request doesn’t just hit a server… 🤯 IP vs MAC Address 🚀 IP = where you are MAC = who you are Router → IP Switch → MAC API call → IP finds network → MAC finds device 🎯 Now networking stops feeling like magic. #Backend #APIs #ComputerNetworking

@TheArnabSaha Nostalgia 😀

Do you remember this wallpaper????

@himanshuu_5 @calcom 💯💯

@imadarsh2002 @calcom Keep it up 💯

🚀 Contributed to @calcom — a real-world SaaS used by thousands 🔧 Fixed a localization bug (Russian i18n) in booking flow 🧠 Explored production-scale Next.js architecture ⚙️ Worked with: Next.js • Node.js • TypeScript • Monorepo 💡 Insight: Small details = BIG impact in production systems #OpenSource #SaaS #NextJS #NodeJS #SoftwareEngineer

🚀 Building an MVP with Node.js + AI (RAG) Problem: Tender PDFs are slow to analyze & error-prone. Solution (WIP): • Node.js backend + APIs • PDF processing • RAG for context-aware outputs • AI for summaries & risk detection 1/2 --- Impact: → Faster decisions → Fewer missed gaps Learning: RAG = retrieval + embeddings + context Building in public to validate a startup idea. #buildinpublic #AI #RAG #NodeJS

@TheArnabSaha @amazon @AWSSupport @awscloud @AWS_Edu @AWS @AWSCloudIndia Congratulations @TheArnabSaha

Just Passed AWS-SAP

Exploring real-world SaaS at scale (Cal.com) 🚀 Today I understood how a monorepo architecture works: • Apps + packages + shared modules • APIs in Next.js backend • Full flow: frontend → backend → DB Why monorepos? • Shared code across apps • Better consistency • Faster dev • Scales with teams Key insight: Monorepos enable scalable + maintainable systems. #OpenSource #Backend #NextJS #SaaS

If your API feels slow, it’s probably not your code 🚀 Most backend issues aren’t logic problems — they’re communication problems. • REST → request/response (Half Duplex) • WebSockets → real-time (Full Duplex) • Events → async flow Example: Dashboard = REST (initial load) + WebSocket (live updates) If you rely only on REST → delays If you design data flow → smooth UX Good engineers don’t just build APIs — they design how systems communicate 🌐 #Backend #NodeJS #APIs #SystemDesign

@twtofsahil @agentbudgetsdk Hey Sahil — Adarsh here 👋 Full-stack dev building AI systems (RAG + multi-agent workflows) and scalable apps with TypeScript/Node ⚡ Love what you’re building with AgentBudget — would be excited to contribute 🚀 GitHub: github.com/devadarshh

hiring a remote engineer for @agentbudgetsdk! drop ur best achievement till now and will discuss the comp :)

@RaeAlisa_ @lucent_ai github.com/devadarshh

I’m hiring a founding engineer @lucent_ai !! - unlimited claude code credits - you know how to build and manage teams of coding agents - remote / sf (will sponsor O1/E3 visas) - $120-160k, 1-3% equity - bonus if you like watching session replays (or hate watching them and want to automate it with AI) comment/DM me your github ☺️

Contributing to real-world SaaS (Cal.com) 🚀 Today I learned: backend isn’t just logic — it’s handling failures across systems. • Async orchestration • Race conditions • Partial success Promise.all vs Promise.allSettled = fail-fast vs resilience This is what production systems look like 💡 #Backend #NodeJS #SaaS #SystemDesign #SoftwareEngineering

Most backend devs ignore this 👇 Computer Networking 🌐🚀 API ≠ function call ❌ It’s: DNS → TCP → HTTP 🔗 That’s where real latency lives ⏱️ • Slow API? DNS 🐌 • Delay? TCP handshake • Failures? Network ⚠️ Not always your code 👀 Great backend devs think in: – Fewer calls 🔁 – Retries 🔄 – Timeouts ⏳ – Resilience 🛡️ Build for production, not localhost 🚀 #Backend #NodeJS #SystemDesign #APIs #WebDevelopment #TechTwitter #Developers 🚀

@madlavak Hii Madhav , I built a post-conversation analytics dashboard MVP as a potential extension layer. I’ve also emailed you with details. Demo: aircaps.landr.xyz Loom: loom.com/share/d3ef5081…

I love YC. Grew monthly revenue 6.5x from $14k to $93k from September to October. Sales & marketing used to be the bane of my existence as a technical founder. Had to hammer it into myself until I was Stockholm syndromed.

@AnchalGupta009 consistency 👍👍👍

Day 79: Design Circular Queue Approach: Fixed-size Array (Ring Buffer) Modulo indexing for wrap-around Optimized enqueue & dequeue ⚡ #LeetCode #CPP #DSA #Queue

@Alxn787 Exactly my situation

I have to get back to the unemployed arc grind I did few months back. I feel like I'm not moving fast enough.