- Implement services in NestJS to handle travel and expense support operations using large language models such as GPT, OpenChat, Mixtral, Claude- Use a combination of models to detect user's intent in a cost-efficient way- Implement APIs for testing prompts using different models- Enable semantic search over itinerary reviews using OpenAI Embeddings and OpenSearch

- Enhanced performance of customer-facing APIs by optimizing slow queries through data normalization, eliminating search on JSON columns in MySQL, migrating aggregation queries to Elasticsearch, implementing state management and batch processing in Quartz jobs.- Implemented warehouse lending flow to fund customers. Established payment settlement protocols, architected idempotent money transfers, enabled overnight payouts.- Founded growth engineering team to implement self-sell flow enabling SMBs to sign up for product directly from marketing page, replacing manual processes previously limited to larger customers. Implementation led to creating 2 microservices and integrating them with main server using Java, Spring Boot, MySQL. Mentored intern who converted to full-time upon project completion.- Implemented per diem policy, prerequisite feature for launching customers in Europe and establishing global presence. Per diem policy enables expense admins to configure spend policy rate definition based on travel destinations.- Led project end-to-end to implement credit card authorization flow for pay later hotel bookings, ensuring secure, automated transmission of payment and booking details to hotels.- Implemented RBAC and ABAC using Spring Security in the expense product to enable internal permissions management. Solution was reused by cross-functional teams to deliver access control management for external customers.

- Architected and implemented webhook authentication mechanism for all microservices using AWS API Gateway, AWS Lambda Functions, and Kafka so that any external service can send webhook request using preferred authentication method such as API key, OAuth 2.0, JWT.- Implemented full-stack application using Spring Boot and Angular to handle Data Subject Access Requests under GDPR and CCPA. Development involved introducing user data obfuscation process in user lifecycle management.- Enhanced implementation of authentication flow using JWTs by adding support for additional claims such as key ID and expiration to enforce token re-encryption for PCI DSS compliance.- Implemented Java client for all microservices to publish security events as part of SIEM flow.