Exploring Tech, Finance & Productivity
Practical articles, free developer tools, and finance calculators. No jargon, no fluff.
Design Tinder (Dating + Matching) - System Design
“Design Tinder” sounds like Instagram with a nicer gesture. Show a photo, swipe left or right, if two people both swipe right they can chat. …
Read MoreJoint Home Loan with Spouse: You Are Missing Rs 3.5 Lakh of Annual Deductions
Most couples put the home loan in one name. Usually the husband’s, sometimes “whoever the bank suggested,” almost always “to keep it …
Read MoreLLM Batch Inference Cuts API Costs in Half - When the Latency Trade-off Is Worth It
Most teams look at the 24-hour SLA on batch APIs and stop reading. That is a mistake. The word “batch” makes people picture overnight …
Read More80CCD(2) Employer NPS: The Tax Break Beyond 80C Most Salaried People Miss
Almost every salaried person knows the Rs 1.5 lakh under 80C and the extra Rs 50,000 under 80CCD(1B). Far fewer know that there is a third …
Read MoreDesign Reddit (Communities + Voting) - System Design
Reddit reads like three easy problems stapled together. Posts in communities: a table. Voting: a counter. Comments: a tree. Say it out loud …
Read MoreDesign Stack Overflow / Quora (Q&A) - System Design
Stack Overflow looks like a CRUD app. Post a question, others post answers, everyone votes, one answer gets accepted, and a number next to …
Read MoreDesign Zoom (Video Conferencing) - System Design
People hear “build Zoom” and reach for the WebRTC tutorial: two peers, an SDP exchange, media flows directly, done. That works for a 1:1 …
Read MoreState Machines Make AI Agents Predictable - Why Most Agent Designs Skip Them
Here is a claim that will annoy most people building agents right now: your agent does not have a bug, it has a state problem. The infinite …
Read MoreDesign Amazon Shopping Cart - System Design
A shopping cart sounds like a toy problem. “Store a list of item IDs and quantities for a user, let them add and remove, show it back.” You …
Read MoreDesign Migrate 1PB of Data to Cloud - System Design
“Move 1PB to the cloud” sounds like a copy job, and people design it like one: point a script at the source, rsync to an S3 bucket, wait. …
Read MoreDesign Slack (Team Messaging) - System Design
People hear “build Slack” and reach for a chat toy: a messages table, a WebSocket, insert on send, push to whoever is connected. That works …
Read MoreEmbedding Model Upgrades Silently Break Production RAG - Here Is How to Handle Them
A new embedding model drops, the benchmarks look great, and someone on your team changes one line of config to point at it. Nothing crashes. …
Read MoreNifty 50 plus Nifty Next 50: You Are Not as Diversified as You Think
There is a very common two-fund starter portfolio doing the rounds on Indian finance forums: put money into a Nifty 50 index fund and a …
Read MoreAccidental Death Rider vs Standalone PA Policy: What Your Term Insurer Does Not Tell You
When you buy a term plan online, the last screen before payment offers you an “Accidental Death Benefit” rider. Rs. 50 lakh of extra cover …
Read MoreDesign Ads Management & Display in Social Feed - System Design
Everyone models an ad server as a lookup: “the user opens the feed, we fetch an ad, we show it, done.” The interviewer lets that sit for a …
Read MoreDesign Distributed Document Editor (Notion / Wikipedia) - System Design
Almost everyone reaches for Google Docs the moment they hear “document editor,” and almost everyone is answering the wrong question. Google …
Read MoreDesign Toll Collection (FASTag) - System Design
A car drives through a toll lane at 30 km/h, an overhead antenna reads its RFID tag, and by the time the nose of the car reaches the barrier …
Read MoreIdempotency Keys Are How You Make Retries Safe in Distributed Systems
The network will lie to you. A client sends POST /charges, the server charges the card, and then the response is lost to a dropped …
Read MoreDatabase Connection Pooling Is the Performance Win Most Teams Skip
Most teams reach for a bigger database instance long before they reach for a connection pooler. That is backwards. A surprising amount of …
Read MoreDesign Flash Sale (6M Free Burgers in 1 Hour) - System Design
“Design a flash sale” sounds like a shopping-cart problem until you write down the actual numbers: Burger King runs a promo, the app has 50 …
Read MoreDeveloper Tools
JSON Formatter
Format, validate & minify JSON instantly in your browser.
Open ToolJWT Decoder
Inspect JWT header, payload, and expiry without sharing tokens.
Open ToolProtobuf Encoder
Encode JSON to Protobuf binary or decode binary back to JSON.
Open ToolRegex Tester
Test regex patterns with real-time matching and group highlights.
Open ToolBase64 Encoder
Encode and decode Base64 strings with a single click.
Open ToolHash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes instantly.
Open ToolUUID Generator
Generate random v4 UUIDs. Copy with one click.
Open ToolUnix Timestamp
Convert between Unix timestamps and human-readable dates.
Open ToolFinance Calculators
SIP Calculator
Calculate monthly SIP growth with the power of compound interest.
EMI Calculator
Find your EMI for home loans, car loans, or personal loans.
1 Crore SIP
Figure out how much SIP you need to build 1 crore.
Emergency Fund
Calculate exactly how much emergency fund you should have.
HRA Calculator
Compute your tax exemption under Section 10(13A).
Investment Growth
Project your portfolio's future value with annual step-ups.
Want to practice coding? Browse 50 DSA problems with clean solutions.