Building scalable web products with clean architecture & great UX

class Engineer {
  name = "Rahatutzaman Rizon";
  role = "Full Stack Developer";
  location = "Dhaka, Bangladesh";

  education = {
    degree: "B.Sc. in ICT",
    university: "Mawlana Bhashani Science and Technology University",
    cgpa: 3.46,
  };

  focus = [
    "Scalable Web Apps",
    "System Design",
    "Clean Architecture",
  ];

  currentlyLearning = ["Cloud", "DevOps", "Distributed Systems"];
}

JavaScript TypeScript Python C++

React Next.js Redux Tailwind CSS Material UI Framer Motion

Node.js Express REST GraphQL

MongoDB MySQL Firebase Vercel Netlify

Git Postman VS Code Trello cPanel

Present

• Developing hotel, visa, and flight booking platforms for real-world users
• Working on search, booking flows, payments, and admin dashboards
• Integrating third-party APIs for availability, pricing, and reservations
• Optimizing performance, reliability, and user experience

Jul 2024 – Oct 2024

• Built MERN-based production features
• Designed REST APIs & optimized queries
• Collaborated with cross-functional teams

Feb 2024 – Apr 2024

• Implemented internal tools & workflows
• Improved process efficiency & stability

Pet adoption & donation platform

• Adoption workflow & fundraising campaigns
• Stripe payment integration
• Role-based dashboard

Tech: React, Tailwind, Node, Express, MongoDB, Firebase, Stripe 🔗 Live: https://pet-adoption-five.vercel.app/

Academic collaboration & tracking system

• Task & progress tracking
• Feedback & team collaboration
• Smooth animations

Tech: React, Tailwind, Firebase, MongoDB, Framer Motion 🔗 Live: https://dainty-choux-b6b746.netlify.app/

• ✅ 500+ problems solved on coding platforms
• 🚀 Multiple full‑stack production projects
• 📈 Consistent GitHub contributions

ID: A03 · Category: Database · Topic: MongoDB Indexing

Key Insight Index fields used in filters + sorts, not everything blindly.

// Example: compound index
db.users.createIndex({ city: 1, createdAt: -1 })

Why it matters Proper indexing dramatically improves query performance at scale.

Quick Win Run explain() before and after adding indexes.

Interview Tip Be ready to explain compound index order based on access patterns.

If you’re building something impactful or hiring a full‑stack engineer — let’s talk.

📧 Email: [email protected]

📅 Date: 2026-01-05 (Generated: 2026-01-05 18:18 UTC) 🆔 Unique ID: A05

• Category: TypeScript
• Topic: Type Safety
• Concept: Prefer unknown over any for external data
• Example: Validate API response with zod
• Common Mistake: Using any hides bugs
• Why it matters: Safer refactors + fewer runtime crashes

• Replace one any with unknown

• Add schema validation + narrowing

• How do you safely parse unknown JSON?

• node -e echo 2>/dev/null

• true

🏷 Tags: TS handbook: Narrowing|Add runtime validation to one API|TypeScript,BestPractice

📅 Date: 2026-01-06 (Generated: 2026-01-06 18:16 UTC) 🆔 Unique ID: A04

• Category: Security
• Topic: Secrets Management
• Concept: Never commit secrets; use GitHub Secrets + env vars
• Example: Use secrets for API keys in Actions
• Common Mistake: Hardcoding keys in code
• Why it matters: Stops leaks + safer deployments

• Rotate keys monthly

• Use OIDC + short-lived creds

• How would you rotate secrets safely?

• echo "Use GitHub Secrets"

• GitHub docs: Encrypted secrets

• Remove one secret from code

🏷 Tags: Security,DevOps

📅 Date: 2026-01-07 (Generated: 2026-01-07 18:17 UTC) 🆔 Unique ID: A04

• Category: Security
• Topic: Secrets Management
• Concept: Never commit secrets; use GitHub Secrets + env vars
• Example: Use secrets for API keys in Actions
• Common Mistake: Hardcoding keys in code
• Why it matters: Stops leaks + safer deployments

• Rotate keys monthly

• Use OIDC + short-lived creds

• How would you rotate secrets safely?

• echo "Use GitHub Secrets"

• GitHub docs: Encrypted secrets

• Remove one secret from code

🏷 Tags: Security,DevOps

📅 Date: 2026-01-08 (Generated: 2026-01-08 18:15 UTC) 🆔 Unique ID: A06

• Category: DevOps
• Topic: Docker Builds
• Concept: Use multi-stage builds to reduce image size
• Example: Build -> copy dist into slim runtime
• Common Mistake: Shipping build tools to prod
• Why it matters: Smaller images + faster deploy

• Add a builder stage today

• Pin base images + SBOM scan

• How do you optimize Docker caching?

• docker --version

• Docker docs: Multi-stage builds

• Reduce image by 30% goal

🏷 Tags: Docker,DevOps

📅 Date: 2026-01-09 (Generated: 2026-01-09 18:17 UTC) 🆔 Unique ID: A09

• Category: Reliability
• Topic: Retries & Timeouts
• Concept: Use timeouts + exponential backoff for network calls
• Example: Retry 3 times with jitter and cap
• Common Mistake: Infinite retries causing outages
• Why it matters: Prevents cascading failures

• Add a 2s timeout everywhere

• Circuit breaker + bulkheads

• How do you prevent retry storms?

• node -e echo 2>/dev/null

• true

🏷 Tags: AWS Architecture: Retry patterns|Add timeout to one client|Reliability,Backend

📅 Date: 2026-01-10 (Generated: 2026-01-10 18:15 UTC) 🆔 Unique ID: A01

• Category: Backend
• Topic: Express Error Handling
• Concept: Use centralized error middleware instead of repeating try/catch
• Example: Wrap async routes with a helper and forward errors
• Common Mistake: Swallowing errors with empty catch blocks
• Why it matters: Reliable APIs + faster debugging

• Add one error handler + log requestId

• Add structured logs + error taxonomy

• How would you design an error strategy for microservices?

• node -e "console.log('Use error middleware')"

• MDN HTTP status codes

• Refactor one route to async-wrapper

🏷 Tags: Node.js,Express,API

📅 Date: 2026-01-11 (Generated: 2026-01-11 18:15 UTC) 🆔 Unique ID: A04

• Category: Security
• Topic: Secrets Management
• Concept: Never commit secrets; use GitHub Secrets + env vars
• Example: Use secrets for API keys in Actions
• Common Mistake: Hardcoding keys in code
• Why it matters: Stops leaks + safer deployments

• Rotate keys monthly

• Use OIDC + short-lived creds

• How would you rotate secrets safely?

• echo "Use GitHub Secrets"

• GitHub docs: Encrypted secrets

• Remove one secret from code

🏷 Tags: Security,DevOps

📅 Date: 2026-01-12 (Generated: 2026-01-12 18:17 UTC) 🆔 Unique ID: A01

• Category: Backend
• Topic: Express Error Handling
• Concept: Use centralized error middleware instead of repeating try/catch
• Example: Wrap async routes with a helper and forward errors
• Common Mistake: Swallowing errors with empty catch blocks
• Why it matters: Reliable APIs + faster debugging

• Add one error handler + log requestId

• Add structured logs + error taxonomy

• How would you design an error strategy for microservices?

• node -e "console.log('Use error middleware')"

• MDN HTTP status codes

• Refactor one route to async-wrapper

🏷 Tags: Node.js,Express,API

📅 Date: 2026-01-13 (Generated: 2026-01-13 18:19 UTC) 🆔 Unique ID: A09

• Category: Reliability
• Topic: Retries & Timeouts
• Concept: Use timeouts + exponential backoff for network calls
• Example: Retry 3 times with jitter and cap
• Common Mistake: Infinite retries causing outages
• Why it matters: Prevents cascading failures

• Add a 2s timeout everywhere

• Circuit breaker + bulkheads

• How do you prevent retry storms?

• node -e echo 2>/dev/null

• true

🏷 Tags: AWS Architecture: Retry patterns|Add timeout to one client|Reliability,Backend

📅 Date: 2026-01-14 (Generated: 2026-01-14 18:18 UTC) 🆔 Unique ID: A05

• Category: TypeScript
• Topic: Type Safety
• Concept: Prefer unknown over any for external data
• Example: Validate API response with zod
• Common Mistake: Using any hides bugs
• Why it matters: Safer refactors + fewer runtime crashes

• Replace one any with unknown

• Add schema validation + narrowing

• How do you safely parse unknown JSON?

• node -e echo 2>/dev/null

• true

🏷 Tags: TS handbook: Narrowing|Add runtime validation to one API|TypeScript,BestPractice

📅 Date: 2026-01-15 (Generated: 2026-01-15 18:22 UTC) 🆔 Unique ID: A07

• Category: System Design
• Topic: Stateless Services
• Concept: Design stateless APIs for easy scaling
• Example: Store session in Redis instead of memory
• Common Mistake: In-memory sessions break scaling
• Why it matters: Horizontal scaling becomes easy

• Add requestId + idempotency key

• Design idempotent endpoints + retries

• What is idempotency and why matters?

• curl --version

• Stripe API idempotency docs

• Make POST idempotent

🏷 Tags: SystemDesign,Backend

📅 Date: 2026-01-16 (Generated: 2026-01-16 18:17 UTC) 🆔 Unique ID: A06

• Category: DevOps
• Topic: Docker Builds
• Concept: Use multi-stage builds to reduce image size
• Example: Build -> copy dist into slim runtime
• Common Mistake: Shipping build tools to prod
• Why it matters: Smaller images + faster deploy

• Add a builder stage today

• Pin base images + SBOM scan

• How do you optimize Docker caching?

• docker --version

• Docker docs: Multi-stage builds

• Reduce image by 30% goal

🏷 Tags: Docker,DevOps

📅 Date: 2026-01-17 (Generated: 2026-01-17 18:14 UTC) 🆔 Unique ID: A01

• Category: Backend
• Topic: Express Error Handling
• Concept: Use centralized error middleware instead of repeating try/catch
• Example: Wrap async routes with a helper and forward errors
• Common Mistake: Swallowing errors with empty catch blocks
• Why it matters: Reliable APIs + faster debugging

• Add one error handler + log requestId

• Add structured logs + error taxonomy

• How would you design an error strategy for microservices?

• node -e "console.log('Use error middleware')"

• MDN HTTP status codes

• Refactor one route to async-wrapper

🏷 Tags: Node.js,Express,API