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I started with one thing: a simple email and password login screen.
Today I build authentication for apps end to end:
Email + password, with verification and password reset
Email OTP
SMS OTP
WhatsApp OTP
Google sign-in
Apple sign-in
Each one taught me something different. Email and password was easy to build and easy to get wrong. Social logins made signup one tap. Apple sign-in is something iOS apps need to plan for early. WhatsApp OTP works well in markets like India, where users already live on WhatsApp.
Along the way I also learned the parts users never see: protecting backend routes, locking down admin access, handling updates without breaking existing users, and keeping one user's data away from another's.
If you're starting to build an app and want login that is secure from day one, I can set it up for you, and add more login methods later as your users grow.
Message me what your app does and who your users are, and I'll tell you which methods to start with.
The network for creativity
Join 1.25M professional creatives like you
Connect with clients, get discovered, and run your business 100% commission-free
Creatives on Contra have earned over $150M and we are just getting started
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I-Sale (demo shopping webapp)
A dynamic online store optimized for discovery and interaction, featuring a real-time live search interface and a streamlined checkout mockup for seamless navigation from cart to completion.
Lovely 😍
Project Title: Secure E-Commerce Backend (Spring Boot, Redis & JWT)
I designed and developed a secure, production-ready e-commerce backend utilizing a clean layered architecture and RESTful principles. Built to handle complex business logic, this project handles everything from user lifecycle management and strict authentication to secure transaction processing and high-speed data retrieval.
Key Engineering Highlights:
Modular Architecture: Engineered 40+ secure CRUD endpoints spanning 6+ core modules: User, Product, Category, Order, and Auth, Wishlist
Advanced Security & RBAC: Implemented Spring Security with custom JWT filters, BCrypt password hashing, and granular Role-Based Access Control enforcing 3 distinct tiers (ADMIN, USER, SELLER).
Transaction Atomicity: Built robust transaction management to guarantee atomicity and data consistency across order placement and cancellation workflows.
Database & Caching Optimization: Optimized MySQL schemas via complex JPA relationships (@OneToMany, @ManyToOne) and Hibernate custom queries. Integrated a Redis caching layer that slashed product retrieval latency by 88.87% (from 3.37 s down to 375 ms).
Containerization: Fully containerized the application stack using Docker Compose for seamless, reproducible local and cloud deployments.
Links to Include:
🌐 Live API Deployment (Render): https://e-commercebackendproject.onrender.com/
💻 GitHub Repository: https://github.com/Amaantheprogrammer/E-CommerceBackendProject
Restaurant Automation System. Automates WhatsApp orders, menu & pricing lookup, estimate generation, PDF invoices, and order processing using n8n, Google Sheets, Gemini AI and WhatsApp Cloud API.
