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SUJEET KUMAR's avatar
SUJEET KUMAR
New Delhi, India
Custom Software | ERP • POS • Weighbridge • Royalty
New to Contra
Custom Software | ERP • POS • Weighbridge • Royalty
Cover image for Restaurant POS & Billing Management
Restaurant POS & Billing Management System Designed and developed a complete Restaurant POS & Billing Management System to streamline restaurant order management, billing, kitchen operations, inventory, and delivery workflows. The system provides a fast and intuitive interface for managing dine-in, takeaway, and delivery orders, with category-based menu browsing and real-time order processing. Key Features: 🍽️ Restaurant POS & Place Order 🧾 Automated restaurant billing 🚚 Dine-in, Takeaway & Delivery management 👨‍🍳 Kitchen Display System (KDS) 📦 Inventory & stock management 📊 Restaurant reports & analytics 💰 GST & tax calculation 🏪 Restaurant entries & master management 📱 Delivery customer & delivery-boy management 🧮 Discounts, service charges, GST & packing charges 🔐 Admin & role-based management ⚡ Fast, responsive POS interface
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Cover image for Uttarakhand Royalty & Weighbridge Management
Uttarakhand Royalty & Weighbridge Management System Developed a real-time Royalty & Weighbridge Management System for mineral transportation operations in Uttarakhand, integrating government mining/royalty services with automated weighbridge verification. The system verifies vehicle, material and weight information using multiple weighbridge cameras, captures first and final weight images, calculates gross, tare and net weight, and manages royalty-related data before submission. Key features: Government royalty / mining API integration Uttarakhand e-Rawanna / e-Transit workflow integration Real-time vehicle verification Automated weighbridge data processing First-weight & final-weight verification Multi-camera image capture and verification Gross, tare & net weight calculation Vehicle and mineral/material tracking Token-based transaction management Lessee & weighbridge configuration Royalty data submission Branch-wise operational management Audit-ready transaction records
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Cover image for Stone Crusher Management & Weighbridge
Stone Crusher Management & Weighbridge ERP Designed and developed a complete Stone Crusher Management & Weighbridge ERP system for managing real-time vehicle operations, token entry, weighbridge transactions, billing, invoices, receipts, and operational reports. Key features: • Real-time vehicle & weighbridge monitoring • Token generation and vehicle tracking • Loading, pending & completed vehicle management • Digital weighbridge / Kanta slip management • Invoice, billing & GST management • Receipt generation • Reports and operational analytics • Multi-user and role-based access • Responsive web dashboard • Database-driven business management Technology: Java, Spring Boot, React, MySQL, REST APIs, Hibernate/JPA
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Cover image for Custom Business Software & ERP
Custom Business Software & ERP Solutions Platform Designed and developed a modern, responsive business software platform for CVSS (Custom Software Solutions) to showcase and promote customized software solutions for businesses. The platform presents an integrated suite of solutions including ERP, Billing & GST, Weighbridge Management, Restaurant POS, Hotel Management, business dashboards, API integrations, and custom software development. The website is designed with a clean, professional UI to clearly communicate complex software solutions, highlight key features, and encourage businesses to book a free demo or connect via WhatsApp. Key highlights: • Modern responsive business website • Custom ERP & business software presentation • Weighbridge & industrial software solutions • Restaurant & Hotel management solutions • Dashboard-focused UI/UX • API & third-party integrations • WhatsApp lead-generation integration • Hosting & deployment support • Conversion-focused landing page design
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Spring Boot(3)
Ayyaz Talat's avatar
Ayyaz Talat
Doha, Qatar
Founder/ CEO
New to Contra
Founder/ CEO
Cover image for Title: mBizzi — Mobile Business Management
Title: mBizzi — Mobile Business Management Platform Short description: Designed and developed a mobile-first business platform focused on simplifying day-to-day business operations through an intuitive, reliable, and scalable application experience. Our contribution: Mobile application architecture, native app development, API integration, authentication, data management, reusable UI components, performance optimization, testing, release engineering, and ongoing product improvements. Services/tags: Mobile Development · Android · iOS · API Integration · Product Engineering · Backend Development · UI/UX Case-study graphic structure To match the PixiKids / SEOForge / Lomo graphics, use: Header mBizzi Mobile Business Management Platform One-liner A mobile-first platform designed to simplify business operations and deliver a fast, intuitive experience for users on the go. The Challenge Build a reliable mobile product that brings essential business workflows into one streamlined experience while maintaining performance, usability, and scalability as the platform grows. The Solution We engineered mBizzi around a modular mobile architecture with secure API integrations, structured data management, reusable application components, and an interface optimized for everyday business workflows. Our Role Mobile application architecture Native mobile development Backend & REST API integration Authentication & user management Data architecture and synchronization UI implementation and reusable components Performance optimization Testing, debugging and release engineering Core Features Business workflow management Secure user authentication Account/profile management Real-time data synchronization Business dashboards Search and structured navigation Notifications and alerts Responsive mobile experience Technical Architecture Use a simple visual: Mobile App → API Gateway → Backend Services → Database with Authentication + Notifications/Cloud Services around the backend. Results & Impact For this section, don't invent numbers. If you have verified mBizzi metrics—downloads, rating, users, transaction volume, performance improvement, etc.—give them to me and we can make this section quantitative. Otherwise use defensible qualitative outcomes: Mobile-First — Business workflows available anywhere Scalable — Modular architecture designed for growth Reliable — Structured API and data integration Optimized — Fast and responsive mobile experience Maintainable — Reusable components and clean architecture And visually, I'd make the mBizzi case study different enough from PixiKids to show range while retaining the same layout system. Then your initial Contra portfolio becomes: PixiKids → parental-control/mobile engineering SEOForge → B2B SaaS Lomo → AI/social/creative platform mBizzi → business/productivity mobile engineering That's a solid four-project foundation for CSP.
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Cover image for Title: SEOForge — Multi-Tenant SEO SaaS
Title: SEOForge — Multi-Tenant SEO SaaS Platform Short description: Built a scalable SaaS platform for agencies and businesses to centralize SEO auditing, keyword tracking, backlink and competitor analysis, Search Console data, reporting, and multi-project management. Our contribution: SaaS architecture, React/TypeScript frontend, Node.js backend, PostgreSQL data layer, third-party SEO/API integrations, authentication and roles, Redis caching, Docker/cloud deployment, and CI/CD. Services/tags: SaaS Development · Web Development · React · TypeScript · Node.js · PostgreSQL · AWS This should probably become your flagship SaaS case study. One caution: your graphic contains specific impact claims such as +200% user growth, +35% client traffic, -60% reporting time, 150 agencies and 4.8/5. Only publish those as factual outcomes if you can substantiate them. Otherwise I'd remove/replace those claims before treating the graphic as a formal case study.
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Cover image for Title: Lomo — AI-Powered Mobile Creative
Title: Lomo — AI-Powered Mobile Creative & Social Platform I would use Lomo, rather than locking the Contra case study to the old “Lomo Graph” branding, since the product is evolving into Lomo Live. Short description: Designed and engineered a native mobile platform combining visual creation, AI-assisted editing, cloud media management and social discovery, with an architecture designed to evolve into community, messaging and real-time live experiences. Our contribution: Product architecture, native iOS/Android engineering, media workflows, backend and cloud integrations, authentication, performance optimization, CI/CD, testing and scalable platform design. Services/tags: Mobile Development · Product Engineering · AI · iOS · Android · Backend Development · Cloud This one is strategically valuable because it's your own product. You aren't merely saying CSP can engineer ambitious products—you can show one being built internally.
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Cover image for Title: PixiKids — iOS & Android
Title: PixiKids — iOS & Android Parental Control Platform Short description: Designed and engineered a cross-platform parental control solution for families, combining screen-time management, application restrictions, activity insights, location features, notifications, and secure cloud synchronization. Our contribution: Native iOS and Android engineering, application architecture, backend/API integration, database and cloud design, performance optimization, testing, CI/CD, and store-release engineering. Services/tags: Mobile Development · iOS · Android · SwiftUI · Kotlin · Firebase · Backend Development The visual is excellent for Contra because it immediately communicates real product complexity + mobile engineering.
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Spring Boot(4)
crystal zhu's avatar
crystal zhu
Hong Kong
Backend Engineer | Workflow, Architecture & API Integration
8
Followers
Backend Engineer | Workflow, Architecture & API Integration
Cover image for From a Business Proposal to a Buildable Backend System
From a Business Proposal to a Buildable Backend System
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11
Cover image for Payment Lifecycle Integration Backend
Payment Lifecycle Integration Backend
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Cover image for AI-Assisted Decision Workflow for Reliable Operations
AI-Assisted Decision Workflow for Reliable Operations
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Cover image for Explainable Decision Engine for Rule-Driven Systems
Explainable Decision Engine for Rule-Driven Systems
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8
Spring Boot(5)
Marvellous Adekunle's avatar
Marvellous Adekunle
Ibadan, Nigeria
Backend Engineer building secure, scalable APIs and transact
11
Followers
Backend Engineer building secure, scalable APIs and transact
Cover image for Taskify API
Taskify API
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Cover image for TravelNest - Hotel Booking Backend System Development
TravelNest - Hotel Booking Backend System Development
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Cover image for ArionWallet Backend System Development
ArionWallet Backend System Development
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Cover image for Development of Scalable Backend for Creator Economy Platform
Development of Scalable Backend for Creator Economy Platform
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Spring Boot(3)
Prabhat Kumar's avatar
Prabhat Kumar
Bengaluru, India
Java Engineer Building AI Automations & Integrations
New to Contra
Java Engineer Building AI Automations & Integrations
Cover image for AI Document Intelligence & Invoice
AI Document Intelligence & Invoice Processing Platform Description Built an AI-powered document intelligence platform designed to automate invoice processing, document classification, data extraction, and approval workflows. The system uses AI, OCR, and workflow automation to process business documents automatically, eliminating manual data entry and reducing processing delays across finance and operations teams. By integrating with existing databases and business systems, the platform transforms unstructured documents into actionable business data. Key Features • AI-powered document analysis • Invoice data extraction • OCR-based document processing • Automated approval workflows • Purchase order matching • Vendor management integration • Document classification • Data validation system • Real-time processing dashboard • Automated reporting and audit trails Business Impact ✓ Reduced manual data entry ✓ Faster invoice processing ✓ Reduced processing errors ✓ Improved financial visibility ✓ Faster approval cycles ✓ Reduced operational costs ✓ Increased productivity across teams Technology Stack • Java • Spring Boot • PostgreSQL • OpenAI API • OCR Processing • REST APIs • Workflow Automation • Analytics Dashboard Results • Automated document processing workflows • Reduced invoice processing time by approximately 75% • Improved data accuracy • Reduced manual administrative effort • Accelerated approval and payment cycles This solution demonstrates how AI-powered document intelligence can automate finance and operational processes while improving accuracy, compliance, and efficiency.
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Cover image for AI Lead Enrichment & CRM
AI Lead Enrichment & CRM Automation Platform Built an AI-powered lead enrichment and CRM automation platform designed to help sales teams identify high-quality prospects, enrich lead data automatically, and streamline outreach workflows. The platform combines AI, external data sources, CRM systems, and workflow automation to reduce manual research while improving lead quality and sales efficiency. Key Features • Automated lead enrichment • Company and contact research • AI-generated personalized outreach emails • CRM synchronization • Lead scoring system • Sales pipeline automation • Contact validation • Automated follow-up workflows • Multi-source data aggregation • Analytics and performance tracking Business Impact ✓ Reduced manual lead research ✓ Increased sales team productivity ✓ Improved lead quality ✓ Faster prospect qualification ✓ Higher outreach efficiency ✓ Better CRM data accuracy ✓ Increased pipeline visibility Technology Stack • Java • Spring Boot • PostgreSQL • OpenAI API • REST APIs • CRM Integrations • Workflow Automation • Analytics Dashboard Results • Reduced lead research time by approximately 80% • Automated prospect enrichment process • Improved CRM data quality • Increased sales team efficiency • Faster lead qualification workflows This solution demonstrates how AI can automate prospect research, improve lead quality, and accelerate sales operations.
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Cover image for AI Customer Support Assistant Built an
AI Customer Support Assistant Built an AI-powered customer support platform designed to automate customer interactions, reduce support workload, and provide instant assistance using company documentation and knowledge base content. The system leverages OpenAI, enterprise knowledge bases, and backend automation to deliver accurate, context-aware responses while seamlessly escalating complex issues to human agents when needed. Key Features: • OpenAI-powered conversational assistant • Knowledge base search and retrieval • FAQ automation system • Context-aware customer responses • Human escalation workflow • Multi-channel support integration • Customer interaction analytics • Real-time response monitoring • REST API architecture • Enterprise-grade backend services Business Impact: ✓ Reduced repetitive support workload ✓ Faster customer response times ✓ 24/7 automated customer assistance ✓ Improved customer satisfaction ✓ Consistent support experiences ✓ Lower operational costs ✓ Increased support team efficiency Technology Stack: • Java • Spring Boot • PostgreSQL • OpenAI API • REST APIs • Docker • Maven • Knowledge Base Integration Results: • Automated approximately 80% of common support requests • Reduced average response time from hours to seconds • Reduced manual support workload by approximately 60% • Improved scalability without increasing support staff This solution demonstrates how AI-powered customer support systems can improve customer experience while significantly reducing operational overhead.
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Cover image for AI Business Operations Automation Suite Built
AI Business Operations Automation Suite Built a centralized AI-powered automation platform designed to streamline internal business operations and eliminate repetitive manual work. The system automates workflows across departments including operations, finance, customer support, reporting, and administration. By integrating AI, APIs, databases, and business tools, the platform significantly reduces operational overhead while improving efficiency and accuracy. Key Features: • Automated invoice processing • AI-powered document analysis • Internal workflow automation • Approval and task management system • Automated report generation • Email and notification automation • CRM and database integration • Real-time analytics dashboard • Role-based access control • Custom business process automation Business Impact: ✓ Reduced manual operational workload ✓ Faster processing of business tasks ✓ Improved team productivity ✓ Reduced human errors ✓ Centralized operational visibility ✓ Scalable automation infrastructure Technology Stack: • Java • Spring Boot • PostgreSQL • OpenAI API • REST APIs • Workflow Automation • Dashboard Analytics This solution demonstrates how AI and automation can transform traditional business operations into efficient, scalable, and data-driven workflows.
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Spring Boot(4)
Raj Kumar Sony's avatar
Raj Kumar Sony
India
Java Backend Engineer building scalable cloud systems
New to Contra
Java Backend Engineer building scalable cloud systems
Cover image for URL Shortener + Analytics 🔗 Designed
URL Shortener + Analytics 🔗 Designed and developed a production-grade URL shortening platform that transforms long URLs into secure, shareable short links while providing powerful real-time analytics and performance insights. The platform enables users to create custom short URLs, monitor click activity, analyze visitor behavior, and manage thousands of links through an intuitive dashboard. Built using a cloud-native, event-driven architecture, it delivers high availability, low-latency redirects, and scalable analytics processing for enterprise-scale applications. 🧑‍💻 What I built: • Generate secure and unique short URLs • Custom aliases and branded short links • Real-time click tracking and analytics • Geographic and device-based insights • Browser and operating system analytics • Referrer and traffic source tracking • QR code generation for every short URL • Link management dashboard • Search, filter, and organize links • REST APIs for seamless integration 🧠 Engineering Highlights • Implemented high-speed redirects using Redis caching • Asynchronous analytics processing with Apache Kafka • Designed a scalable event-driven architecture for millions of requests • Optimized database performance with indexing and query tuning • Secure authentication using Spring Security and JWT • Built RESTful APIs following clean architecture principles • Cloud-ready deployment with Docker and AWS • Enterprise-grade architecture focused on scalability, reliability, and maintainability 🛠️ Tech Stack: Java 21 • Spring Boot • PostgreSQL • Redis • Apache Kafka • REST APIs • Spring Security • JWT • Docker • AWS • OpenAPI/Swagger Status: Completed ✅
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Cover image for Task Management System 🚀 Designed and
Task Management System 🚀 Designed and developed a modern task management platform that helps teams plan, organize, collaborate, and track work in real time. The application streamlines project execution through intuitive task management, Kanban workflows, team collaboration, reporting, deadline tracking, and real-time notifications. Built with a cloud-native architecture, it provides a secure, scalable, and high-performance solution that enables organizations to manage multiple projects, improve team productivity, and monitor progress from a centralized dashboard across desktop and mobile devices. 🧑‍💻 What I built: • Project and workspace management • Task creation, assignment, and prioritization • Kanban board and list-based workflows • Team collaboration and member management • Real-time dashboard and analytics • Calendar and deadline management • File attachments and task comments • Activity timeline and audit history • Role-based access control (RBAC) • Real-time notifications and alerts • Responsive web and mobile interface 🧠 Engineering Highlights • Designed a scalable microservices-based architecture for enterprise workloads • Optimized dashboard queries using caching and efficient database indexing • Built real-time collaboration using event-driven communication • Implemented secure authentication with Spring Security and JWT • Developed modular RESTful APIs following clean architecture principles • Containerized the application using Docker for consistent deployments • Cloud-ready architecture optimized for AWS infrastructure • Built for horizontal scalability, maintainability, and high availability 🛠️ Tech Stack: Java 21 • Spring Boot • React • PostgreSQL • Redis • REST APIs • Spring Security • JWT • Docker • AWS • OpenAPI/Swagger Status: Completed ✅
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Cover image for Rate Limiter as a Service
Rate Limiter as a Service ⚡ Designed and developed a production-grade Rate Limiter as a Service that protects APIs from abuse, controls request traffic, and ensures fair resource utilization across distributed applications. The platform enables developers to define flexible rate limiting policies, monitor API consumption in real time, and enforce request quotas with minimal latency. Built using a cloud-native architecture, it supports multiple rate limiting algorithms, horizontal scaling, and high availability, making it suitable for modern microservices and enterprise API platforms. 🧑‍💻 What I built: • API key, client, user, and IP-based rate limiting • Configurable rate limiting policies • Sliding Window, Fixed Window, and Token Bucket algorithms • Real-time request monitoring dashboard • Client usage analytics and reporting • Rate limit utilization tracking • Alert management for unusual traffic • REST APIs for policy administration • Secure API authentication and authorization • Responsive web dashboard for monitoring and management 🧠 Engineering Highlights • Built a distributed rate limiting system using Redis for high-speed request tracking • Designed stateless services for horizontal scalability across multiple instances • Optimized request validation with low-latency in-memory operations • Implemented configurable throttling strategies for different client requirements • Secure authentication using Spring Security and JWT • Cloud-ready deployment with Docker and AWS • Fault-tolerant architecture with graceful degradation during high traffic • Production-ready modular architecture following clean coding principles 🛠️ Tech Stack: Java 21 • Spring Boot • Redis • PostgreSQL • REST APIs • Spring Security • JWT • Docker • AWS • OpenAPI/Swagger Status: Completed ✅
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Cover image for Social Feed Platform 🌐 Designed and
Social Feed Platform 🌐 Designed and developed a modern social networking platform that enables users to connect, share content, engage with communities, and communicate in real time. The application provides personalized news feeds, user profiles, post creation, social interactions, trending content discovery, and instant notifications through a responsive and intuitive interface. Built using a cloud-native architecture, it delivers high performance, security, scalability, and a seamless user experience across desktop and mobile devices. 🧑‍💻 What I built: • User registration and secure authentication • Personalized user profiles • Create, edit, and delete posts • Like, comment, and share functionality • Follow and unfollow users • Personalized social feed • Trending hashtags and content discovery • User and post search • Real-time notifications using WebSocket • Responsive web and mobile interface 🧠 Engineering Highlights • Designed with a scalable microservices architecture • Real-time communication using WebSocket • Optimized data retrieval with Redis caching • Secure authentication using JWT and Spring Security • RESTful APIs with clean layered architecture • Cloud-ready deployment using Docker and AWS • High-performance backend built for enterprise-scale workloads • Production-ready architecture with modular and maintainable codebase 🛠️ Tech Stack: Java 21 • Spring Boot • React • PostgreSQL • Redis • WebSocket • REST APIs • Spring Security • JWT • Docker • AWS Status: Completed ✅
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Spring Boot(5)
Artem Gryn's avatar
Artem Gryn
Stockholm, Sweden
Expert Backend Engineer | Java, Spring Boot, Cloud
Expert Backend Engineer | Java, Spring Boot, Cloud
Cover image for Pay-by-parts system
Pay-by-parts system
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Cover image for Anti money laundry/know your customer application for Finance
Anti money laundry/know your customer application for Finance
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Cover image for Cloud based product for managing metadata in media
Cloud based product for managing metadata in media
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Spring Boot(3)
Drivyesh Modi's avatar
Drivyesh Modi
India
Growth is the only constant to achieve Perfection
Growth is the only constant to achieve Perfection
Cover image for Technical Mock interviews and coaching for big firms
Technical Mock interviews and coaching for big firms
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Cover image for Java Project and Bug Fixing
Java Project and Bug Fixing
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Cover image for Java Application Project
Java Application Project
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