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Dennis Hughes

@dennishughes

Senior Software Engineer at Writer architecting the AI workflow runtime behind AI Studio and Palmyra applications.

At Writer, I architect the core AI workflow runtime platform behind AI Studio and Palmyra applications. I designed its orchestration engine and retrieval service, including permission-scoped access and source attribution.

I previously led backend modernization and cloud migration work at Thoughtworks, including a Java microservices platform on AWS for a FinTech client's payment system. I also built event-driven transaction processing and data ingestion services for client platforms.

At Amazon, I owned backend services and a resilient async workflow system, improving API latency and service observability. Earlier at PagerDuty, I developed event processing components and integrations for its alerting platform.

Experience

Work history, roles, and key accomplishments

Current

Senior Software Engineer

Current

Writer

Jul 2023 - Present (3 years 3 months)

Architected and led the development of Writer's core AI workflow runtime platform, a scalable Python service executing LLM-backed workflows for thousands of enterprise customers. Designed the platform's state-machine orchestration engine, reducing workflow execution failures by 30% and improving developer throughput.

Senior Consultant Developer

Thoughtworks

Jul 2021 - Jun 2023 (1 year 11 months)

Led backend modernization and cloud migration for a FinTech client's core payment processing system, architecting a Java-based microservices platform on AWS. Designed and implemented a real-time event-driven architecture using Kafka and AWS Lambda, and built scalable data ingestion APIs for a healthcare analytics platform.

Java AWS Microservices Kafka Lambda Event Driven Architecture Data Ingestion PostgreSQL CI CD Infrastructure as Code Datadog SLOs Incident Response Technical Leadership Mentorship

Consultant Developer

Thoughtworks

Jul 2019 - Jun 2021 (1 year 11 months)

Contributed to backend modernization and cloud migration projects, including architecting a multi-tenant SaaS data platform for a B2B startup. Established platform engineering practices and drove production readiness across engagements.

Java AWS Microservices Kafka Lambda Event Driven Architecture Data Ingestion PostgreSQL CI CD Infrastructure as Code Datadog SLOs Incident Response Technical Leadership Mentorship

Software Development Engineer II

Amazon

Aug 2016 - Jun 2019 (2 years 10 months)

Owned end-to-end architecture and operation of high-throughput Java/Python backend services serving millions of daily requests with 99.99% availability. Designed a resilient multi-step async workflow system using SQS and DynamoDB, and led performance optimization reducing p95 latency by 40%.

Java Python AWS Amazon SQS DynamoDB Cloudwatch Microservices Distributed Systems Performance Optimization Caching Observability SLOs Incident Response Mentorship

Software Engineer II; Software Engineer

PagerDuty

Jun 2013 - Jul 2016 (3 years 1 month)

Developed core components of PagerDuty's event ingestion and processing pipeline using Ruby on Rails and Python, building REST APIs and background workers that handled millions of alerts daily. Enhanced operational resilience and contributed to early microservice boundary design.