Senior Backend Technical Lead (APIs/Security)

• Build secure API ecosystems using JWT authentication, OAuth2 token handling, RBAC, request validation, API versioning, documented API contracts, and secure access control. KRISHAN KANT SAGAR

Senior Technical Lead — Backend Engineering Java, Spring Boot, Node.js, Laravel, Microservices

+91-950******* *******************@*****.*** linkedin.com/in/krishankant-sagar-43597299 Baran, Rajasthan, India PROFESSIONAL SUMMARY

Senior Technical Lead / Backend-Focused Full Stack Developer with 10+ years of experience designing, developing, and delivering scalable enterprise applications, backend platforms, API frameworks, and cloud-ready SaaS systems for US and Australian clients. Deep hands-on expertise in Node.js, Express.js, PHP, and Laravel, with proven experience building secure REST APIs, microservices- oriented architecture, multi-tenant SaaS platforms, and high-performance backend systems across fintech, banking, legal, healthcare, insurance, and education domains. Actively expanding into Java and Spring Boot, with applied experience contributing to a production Java-based REST API service (bug fixes, feature enhancements, code reviews) alongside self-directed Spring Boot API development

— bringing a strong, transferable backend foundation (API design, database optimization, authentication/security, queues, CI/CD) to Java backend teams. Proven ability to lead engineering teams, mentor developers, and deliver secure, maintainable, enterprise-grade applications for international clients.

CORE SKILLS

• Backend Engineering: Node.js, Express.js, PHP, Laravel, Java (Working Knowledge), Spring Boot, Spring MVC, REST APIs, API Framework Development, Core Backend Modules, Backend Architecture, High-Performance Backend Systems

• API Design & Integration: RESTful APIs, API Documentation, Swagger/OpenAPI Concepts, Postman, API Versioning, API Contracts, Third-Party API Integration

• Architecture: Microservices-Oriented Architecture, Modular Backend Design, Scalable Architecture, System Design, Multi- Tenant SaaS, MVC, OOP, SOLID Principles

• Databases: MySQL, PostgreSQL, MongoDB, SQL, NoSQL, Database Integration, Query Optimization, Indexing, Database Performance Tuning

• Queues & Async Processing: Laravel Queues, Background Jobs, Redis, Queue-Based Processing, Asynchronous Workflows, Message Queue Concepts, Kafka/RabbitMQ Awareness

• Cloud & DevOps: AWS S3, Docker, Git, GitHub Actions, CI/CD Pipelines, Linux Server, Deployment Support, Cloud- Ready Application Design

• Security: JWT, OAuth2, RBAC, OWASP Awareness, Secure API Design, Secure Coding, SQL Injection Prevention, Input Validation, Data Protection

• Testing & Quality: PHPUnit, Unit Testing, API Testing, Code Reviews, Automated Testing, Production Troubleshooting

• Leadership: Technical Leadership, Team Mentoring, Requirement Analysis, Agile/Scrum, Client Communication, Technical Decision-Making

PROFESSIONAL EXPERIENCE

Senior Software Developer / Technical Lead 04/2016 – Present RadianSys Technologies Pvt. Ltd — Technology services company delivering enterprise software solutions for US and Australian clients

• Lead end-to-end backend and full-stack development of enterprise applications and SaaS platforms using Node.js, Express.js, PHP, Laravel, React.js, REST APIs, MySQL, PostgreSQL, MongoDB, Redis, Docker, Git, CI/CD, and AWS S3.

• Contribute to bug fixes, feature enhancements, and code reviews within a Java/Spring Boot–based REST API service, working alongside the Java team to resolve production defects, improve endpoint reliability, and maintain code quality — building applied, interview-ready Java backend experience.

• Develop API frameworks, reusable backend modules, secure REST APIs, third-party integrations, database workflows, and scalable backend services for enterprise-grade applications.

• Act as senior technical owner for client projects, handling requirement analysis, backend architecture, system design, coding, code reviews, deployment support, production troubleshooting, and technical communication.

• Design and implement microservices-oriented and modular backend architecture using REST APIs, service-based components, authentication layers, background jobs, and database-driven workflows.

• Build secure API ecosystems using JWT authentication, OAuth2 token handling, RBAC, request validation, API versioning, documented API contracts, and secure access control.

• Collaborate with frontend, QA, DevOps, product, and client teams to ensure reliable API integration, release planning, sprint execution, and high-quality production delivery.

• Build integrations with external tools and platforms including Stripe, Stripe Connect, Plaid API, CRS Credit Score API, Google Analytics API, payment gateways, document processing APIs, and third-party enterprise systems.

• Improve backend performance through SQL query optimization, indexing, schema redesign, Redis caching, queue-based processing, background jobs, and refactoring legacy stored procedures into maintainable application code.

• Implement asynchronous processing using Laravel Queues, Redis, background jobs, scheduled workers, email dispatch queues, report generation jobs, and high-volume data processing workflows.

• Support CI/CD and deployment workflows using Git, GitHub Actions, Docker, Linux servers, AWS S3, Postman, and environment-based release processes.

• Create and maintain API documentation using Postman collections, structured API contracts, endpoint documentation, request/response formats, and Swagger/OpenAPI-ready API design practices.

• Conduct code reviews for junior and mid-level developers with focus on SOLID principles, performance, secure coding, maintainability, API quality, and architecture consistency.

• Mentor developers, estimate development effort, guide technical implementation, and collaborate with international clients in Agile/Scrum delivery environments.

• Delivered a Wells Fargo customer support platform that reached 1M+ user sessions in the first month and reduced average call handling time by 2–3 minutes.

• Delivered and maintained production applications across banking, fintech, legal, healthcare, insurance, education, smart home, and subscription-based SaaS domains with zero major production incidents. Web Developer 01/2015 – 03/2016

Sai Educare Pvt. Ltd — Educational technology company developing online learning solutions

• Built and maintained PHP, MySQL, JavaScript, HTML, and CSS features for an Australian learning management system.

• Developed backend modules, database-driven workflows, user-facing features, and production bug fixes for LMS platforms.

• Maintained a PrestaShop e-commerce platform, developed custom modules, and supported product/order workflows.

• Worked on PHP-based application development, MySQL database integration, JavaScript enhancements, and production issue resolution.

KEY PROJECTS

Wells Fargo – Net Banking Customer Support Platform Tech: Node.js, Express.js, REST APIs, Bootstrap, Pug, jQuery, Google Analytics API

• Built backend and templating layer for a bilingual English/Spanish customer support platform used by Wells Fargo executives.

• Developed backend APIs and workflows to support guided customer support and mobile app redirection.

• Integrated Google Analytics API for session tracking, interaction analytics, and user behavior monitoring.

• Delivered weekly client builds in two-week Agile cycles.

• Platform crossed 1M+ user sessions in the first month and reduced average call handling time by 2–3 minutes. Polaris – FinTech Budget & Transaction Tracker

Tech: Node.js, Express.js, PostgreSQL, Plaid API, CRS API, JWT, OAuth2

• Built secure backend APIs for bank account linking, transaction synchronization, category-based spending, financial goals, and credit score workflows.

• Integrated Plaid API and CRS credit score API for sensitive financial data processing.

• Implemented OAuth2 token handling, JWT authentication, secure API flows, and protected transaction data workflows.

• Designed PostgreSQL database integration for transaction history, credit score records, account metadata, and financial goal tracking.

Landlord.FingerAndFinger – AI-Enabled Legal Case Management Platform Tech: Laravel, React.js, MySQL, REST API, Multi-Tenant Architecture, JWT

• Designed multi-tenant SaaS architecture for multiple law firms using one shared platform with strict tenant isolation.

• Built backend REST APIs and collaborated with React.js frontend teams for case tracking, document workflows, and role- based collaboration.

• Built backend REST APIs and collaborated with React.js frontend teams for case tracking, document workflows, and role- based collaboration.

• Integrated AI-driven document processing through REST APIs with retry logic, error handling, and secure data handling.

• Optimized queries and adjusted backend architecture as production case volume increased. CEU Cloud – Digital Document Management SaaS

Tech: Laravel, Eloquent ORM, MySQL, REST API, Stripe, RBAC

• Built admin portal for user management, document storage, access control, and automated upload workflows.

• Designed scalable Laravel APIs and database workflows for a document-heavy SaaS platform.

• Implemented Stripe subscriptions and in-app purchase flows using secure webhook handling.

• Designed transcript-to-certification mapping logic for institutional compliance requirements.

• Platform reached 30,000+ active users within the first year. Money Buy App – P2P Fund Pooling Platform

Tech: Laravel, Stripe Connect API, Payment Gateway Integration

• Built fund chain logic and integrated Stripe Connect for connected account creation, customer wallets, and bank payouts.

• Developed secure payment gateway workflows for account creation, payout processing, and transaction handling.

• Handled complex multi-party fund movement workflows involving wallets, bank payouts, and Stripe Connect. Star Casualty – Insurance Platform Modernization

Tech: Laravel, Livewire, MySQL, XML Data Migration

• Rewrote legacy insurance platform business logic in Laravel with Livewire components.

• Built transformation layer to convert XML responses from the old system into normalized MySQL tables without data loss.

• Improved platform maintainability and reduced dependency on legacy application logic. NorthStar Home – Smart Home Security & Automation App Tech: Node.js, REST API, Push Notifications, Real-Time Data

• Built backend APIs for a home security app across iOS, iPad, and Apple Watch.

• Supported real-time alarm control, live video, device management, push notifications, and event history APIs.

• Delivered API support across 19 language locales for an active US user base. Aesthetic Records – Healthcare SaaS Platform

Tech: Laravel, REST API, MySQL, Multi-Portal Architecture

• Delivered new API features for an existing healthcare SaaS platform used by US healthcare clients.

• Wrote API documentation for each new endpoint and coordinated with frontend teams to reduce integration delays.

• Supported multi-portal architecture with clean API additions while avoiding regression in existing integrations. Java REST API Contributions & Self-Directed Spring Boot Learning (In Progress) Tech: Java, Spring Boot, Spring MVC, REST API

• Contributing to bug fixes, small feature additions, and code reviews on an in-house Java/Spring Boot REST API service alongside primary Node.js/Laravel responsibilities.

• Self-directed study building REST APIs with Spring Boot and Spring MVC to strengthen Java backend fundamentals for future Java-focused roles.

KEY ACHIEVEMENTS

• Delivered a Wells Fargo customer support platform with 1M+ user sessions in the first month.

• Reduced average customer call handling time by 2–3 minutes through guided net banking support workflows.

• Built CEU Cloud platform that reached 30,000+ active users within year one.

• Designed multi-tenant legal SaaS architecture with strict data isolation across multiple law firms.

• Built secure backend systems across banking, fintech, healthcare, legal, insurance, education, and SaaS domains.

• Led code reviews, mentored developers, and supported international client delivery across US and Australian projects.

• Maintained 10+ years of production delivery experience with zero major incidents.

• Currently deepening Java/Spring Boot capability through hands-on production contributions and self-directed REST API development.

• Currently deepening Java/Spring Boot capability through hands-on production contributions and self-directed REST API development.

EDUCATION

B.Tech – Information Technology

Arya College of Engineering & Research Centre 08/2010 – 05/2014 Rajasthan TRAINING

Microsoft Visual Studio Platform – ASP.NET, C#, and SQL Server Development Training Programme

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