Waqar Haider

Java (Spring Boot) Tech Lead

Algo • Fulltime

Feb 2024 - Present • 2 yrs 9 mos

● Designed and developed DarkStore Supply order creation and committing flow under Standard PDR replenishment for JB Hifi only. ● Optimized Big query to 70x time faster using CTE for History Export Batch Job used by multiple retailers and tenantt. ● Integrated HB HiFi, Meta, and Microsoft order-commit APIs into the V-Inventory ecosystem, implementing comprehensive external API logging, request validation, and business validations for product, pricing, and active-store eligibility. ● Designed and enhanced the JB Hi-Fi AR Data Feed API flow to ingest retailer inventory data in real time, persist API requests/responses, stage and validate inbound inventory records, generate/reuse control numbers safely across concurrent API requests, and support scheduled migration of validated records into inventory fact/history processing while maintaining auditability and operational logging. ● Implemented an Ignore Casepack Rounding option in the Standard Replenishment flow, allowing replenishment quantities to bypass casepack rounding when configured while preserving existing min/max, inventory deduction, and standard calculation behavior for normal replenishment runs. ● Led EDI onboarding for MS FNAC and MS GameStop CA, including retailer-specific sales and inventory feed integration, validation, and migration of 4 years of historical sales/inventory data to enable seamless replenishment, forecasting, and operational continuity within the V-Inventory ecosystem. ● Managed a team of 3 developers, overseeing PR reviews, bug fixes, code quality checks, testing requirements, and safe merges into the master branch to maintain delivery quality and production stability. ● Document APIs with Swagger UI and implement JPA-based data access layers against Oracle DB. ● Collaborate with cross-functional teams in Agile/Scrum ceremonies, contributing to requirement gathering and solution design for FinTech and supply-chain clients.

Java Software Engineer (Remote)

ScaleTech Solutions • Fulltime

Oct 2022 - Nov 2023 • 1 yr 1 mo

Built and maintained REST APIs integrating Infonova and CloudBilling payment and billing platforms for a German FinTech client, supporting reliable communication between financial services and downstream business systems. ● Developed backend services for payment, billing, and transaction-related workflows using Java, Spring Boot, JPA/Hibernate, and Oracle DB, following scalable MVC and layered architecture principles. ● Implemented transaction validation, request/response handling, and business-rule validations to ensure accurate and consistent processing of financial operations across integrated systems. ● Integrated and consumed REST/SOAP-based financial services, handling API communication, payload transformation, error responses, and exception scenarios across external payment and billing platforms. ● Applied Spring Security and secure API integration practices to protect service endpoints and support secure communication with external financial systems. ● Designed and optimized Oracle database big queries and JPA-based data access layers for transaction and billing-related data, focusing on data consistency and application performance. ● Implemented robust error handling, logging, and monitoring for payment and billing integrations to improve troubleshooting, operational visibility, and system reliability. ● Participated in Agile/Scrum sprints, client requirement sessions, and system design discussions within a distributed remote team. ● Documented APIs via Swagger UI and validated integrations using SOAP UI, JUnit, and Mockito.

Software Engineer

Datics AI • Fulltime

Oct 2021 - Apr 2022 • 6 mos

Built RESTful APIs with Node.js and Express.js, and designed scalable, document-oriented schemas using MongoDB. ● Implemented Angular-based SPA components along with middleware for authentication, logging, and centralized error handling. ● Applied asynchronous programming patterns (callbacks, Promises, async/await) and managed dependencies with npm. ● Implemented secure authentication and authorization mechanisms for client-server communication.