Sean Harkin

Senior Software Engineer at Cogny

Improved RAG pipelines: enhanced embedding strategies, OCR processes, and integrated OpenAI and Cohere. Optimized vector database for retrieval performance and accuracy. Built and maintained a scalable NestJS API backend powered by PostgreSQL. Partnered with CTO on an asynchronous document processing system using LangChain, Kafka, and OpenAI.

Software Engineer at 3Advance

Developed and maintained GraphQL APIs for mobile apps using AWS Amplify, Node.js, and serverless architecture. Designed efficient database schemas and built admin panels in Retool for internal teams.

Software Engineer at Immobilien Scout24, Berlin

Built and maintained mobile REST APIs (Node.js, Express, Serverless); migrated monolithic APIs to microservices. Implemented CI/CD pipelines in TeamCity and Jenkins; managed AWS infra via CloudFormation. Built React tooling for app testing; onboarded and mentored new engineers.

Software Engineer at Fidelity Investments, Dublin

Built an Angular web app with a Serverless Node.js backend on AWS; managed CI/CD on Jenkins and infrastructure via CloudFormation.