Robert Simmons.

20+ years building consumer products GenAI  ·  Personalisation  ·  Platform Engineering
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01 — About

About Robert Simmons

Turning ambiguous ideas into working prototypes that help teams align and move fast.

I'm a Senior Software Engineer with 20+ years of experience building consumer products at scale — most recently focused on Python-led GenAI systems, retail personalisation, and production-scale experimentation at Amazon.

My strongest skill is moving quickly from concept to working prototype, making abstract ideas tangible before major engineering investment is committed. I led the end-to-end delivery of an LLM-powered personalisation system that serves 100M+ customers and generated 500M+ personalised experiences — from prototyping through to serving, caching and customer-facing rendering.

Earlier in my career I built and owned the Alexa iOS SDK as sole engineer for approximately four years, and served as an internal security certifier completing 38+ security reviews across engineering teams at Amazon.

I'm strongest in environments where pace, hands-on leadership and a startup mentality matter — building something new, scaling a platform, or proving a product concept that unlocks the next stage of investment.

02 — Skills

Core Capabilities

Core

Python GenAI Prototyping LLM Evaluation Retail Personalisation Backend Architecture Experimentation Distributed Systems Event-driven Pipelines Observability CI/CD

Languages & Platforms

TypeScript Swift Objective-C Java Kotlin React Native FastAPI

Cloud & Systems

AWS Lambda / Lambda@Edge SQS & SNS EventBridge S3 / EC2 / VPC Bedrock Batch Caching

Security & Engineering Quality

Threat Modelling Penetration Testing OWASP Secure SDLC Code Review Mentoring

03 — Experience

Where I've Worked

Senior Software Engineer

Amazon

Current Role

  • Led end-to-end delivery of LLM-powered homepage personalisation — spanning content generation, evaluation, trust gating, infrastructure, serving, caching and customer-facing rendering.
  • Delivered systems serving 100M+ customers and generating 500M+ personalised experiences in under 30 days — from concept to live experiment.
  • Built an event-driven daily regeneration pipeline with cost controls, prompt optimisation, model selection, evaluation loops and production-grade operational guardrails.
  • Designed quality controls including LLM-as-a-judge evaluation, Wilson confidence interval sampling, and trust & safety gating for a storefront-facing AI experience.
  • Led a team of 5 engineers on a high-visibility retail initiative — owned critical path and all architecture decisions.
  • Led iOS delivery for Rufus chat voice input, adding depth in customer-facing AI across platforms.

Software Engineer II

Amazon

Previous Role

  • Sole owner of the Alexa iOS SDK for approximately 4 years — architecting and delivering wake word support, HTTP/2 downchannel streaming, performance improvements and Amazon Music integration.
  • Served as an internal security certifier, completing 38+ security reviews and building RAG-based screening patterns that reduced review cycles from weeks to days.
  • Reviewed 3,800+ pull requests over tenure — consistently raising the bar for code quality, maintainability and safe change.
  • Mentored successors to take over SDK ownership cleanly and sustainably, investing in long-term team capability.

Engineering Career Across Multiple Roles

Microsoft

Earlier Career

  • Built consumer messaging features at GroupMe — web and application layers using Ruby on Rails, PostgreSQL and AngularJS. Implemented an internal beta testing framework for faster iteration and earlier feedback loops.
  • Contributed to desktop software delivery on Skype Desktop in a large-scale consumer communications environment.
  • Improved test strategy, automation and release quality across Skype — shaping engineering quality across multiple delivery teams.
  • Worked on software quality and test automation for large consumer platforms on MSN.
  • Began career in programme and product delivery across Microsoft teams — progressing from student intern to senior software engineer over a decade at the company.

04 — Projects

Selected Work

Personal Project  ·  Open Source

Retail Loyalty AI Shopping Assistant

An end-to-end AI shopping assistant demonstrating personalised retail experiences — customer profiling, KNN-based recommendations, and conversational commerce with basket management and order placement. Built to showcase startup-style prototyping: concept through to a working browser-based SPA with full test coverage. A direct expression of the kind of rapid, high-quality prototyping that defines how I approach new problems.

Python FastAPI Polars scikit-learn KNN Claude Haiku Tool-driven Chat Single-Page App
View on GitHub

05 — Community

Leadership & Community

0

Interns coached & mentored

0

Engineers reached fortnightly

0

Pull requests reviewed

Coaching & Mentoring

Coached 8+ interns and currently mentoring 2 apprentices with direct technical guidance, career advice, and structured learning paths.

Lightning Talks

Runs a fortnightly lightning talk series for 50+ engineers — creating space to share solved problems, surface better practices and build cross-team connection.

Engineering Standards

Known for high standards in code quality, maintainability, testing discipline and safe change — demonstrated through 3,800+ pull requests reviewed over tenure.

Security Certifier

Served as an internal security certifier completing 38+ reviews, and built RAG-based screening tools that cut review cycles from weeks to days.

Volunteering

Mums in Technology

Instructor — Web Technologies & Programming Fundamentals

Earlier in career

Volunteered with this group of women over a 6-week programme, delivering hands-on training in web technologies and the fundamentals of programming. One of the most rewarding things I've done — seeing people find their confidence with code for the first time.

06 — Certifications

Credentials

Amazon

AWS Certified AI Practitioner

Issued 2026

Microsoft

Exam 70-562 — TS: .NET Framework 3.5, ASP.NET Application Development

Issued 2009

BCS

ISTQB-BCS Certified Tester Foundation Level

Issued 2011

07 — Connect

Let's Connect

Open to conversations about GenAI, personalisation, platform engineering, or roles where pace and hands-on technical leadership matter.

LinkedIn GitHub