Developer • Creator • Tech Educator

I Build Software, Create Tools & Teach Code.

Developer by craft, educator by choice. With 15+ years in software engineering, I build scalable web platforms, craft free developer tools, and distill complex technical concepts into clear mental models for developers worldwide.

15+ Yrs Experience
9+ Projects Built
6+ Articles
50+ Interview Q&As
20+ Technologies
1+ Subscribers
santosh_shelar.profile
Santosh Shelar — Developer, Creator & Tech Educator
Santosh Shelar
Developer • Creator • Tech Educator

Toolbelt

Technologies & Languages I Use

Knowledge Hub

Learn & Explore Free Developer Resources

Simplified concepts, in-depth tutorials, and instant developer tools.

Interactive Tool Speed Mode

Interview Flashcards

Master frontend, backend, and system design concepts with active recall flip cards, spaced review, and timed interview mode.

In-Browser Sandbox Live Editor

Web IDE & Playground

Run HTML, CSS, and JavaScript directly in your browser. Perfect for testing interview code snippets, experiments, and prototypes.

Open Web IDE →
AI Engineering

AI Prompt Library

Battle-tested prompts for code refactoring, architecture design, automated test generation, and AI pair programming.

Explore Prompts →
Articles & Guides

Technical Blog

In-depth guides on JavaScript internals, backend architectures, performance tuning, and software engineering principles.

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Speed Drills 60s Mode

CodeShot — Speed Challenges

Daily bite-sized coding challenges and rapid logic drills to build speed and confidence before interviews.

Open CodeShot.in ↗

Daily Challenge

Question of the Day

A new challenge every day — click the card to reveal the answer.

NodeJS 🟡 Intermediate Click to reveal

What is error-handling middleware in Express?

NodeJS ErrorHandling

Writing

Latest Articles & Tutorials

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Join the Developer Digest

Join 500+ developers getting my best system design concepts, coding tutorials, and engineering mental models every month. No spam, just high-signal content.

Recommendations

Words from Colleagues & Friends

Heartfelt feedback and recommendations from my professional colleagues and friends who have supported my journey.

"I had the privilege of working with Santosh when I joined NSE Cogencis as a Python Developer. At that time, I was new to many aspects of software development, and Santosh play..."

Prashant Bhosale
Python developer @ NSE COGENCIS

"Santosh,is a highly skilled software developer with excellent knowledge of development. His strength lies in transforming complex designs into well-structured and efficient co..."

Sanket Asrudkar
UI UX @ NSE Cogencis