Hi, my name is

Nick Theodoulou

I'm a Tech Lead based in London.

About Me

Nick Theodoulou profile picture

As a Tech Lead with over 6 years of experience in TypeScript, React, Node.js, and AWS, I lead a cross-functional team of 12 (6 engineers, 1 QA, 1 SDET, product manager, agile delivery lead, business analyst, and UX designer) delivering high-quality scalable solutions for Dunelm's digital platform.

Leadership Impact

I drive engineering excellence through strategic technical leadership and team empowerment. Under my leadership, 2 engineers have been promoted (graduate to junior in 1 year, associate to mid-level), and team velocity increased by over 20% in 6 months. I was awarded Dunelm Technology's 2024 Mentorship Award for "making a significant impact by helping others unlock their potential and grow in their careers". I've interviewed and onboarded 3 engineers in the last 18 months, creating extensive resources that were shared across the wider engineering department.

Technical Strategy & Architecture

I lead architectural decisions and long-term technical strategy, working closely with product managers, UX designers, and stakeholders to align technical solutions with business needs. Recent examples include completely redesigning the Content Delivery Application (Fastly Compute@Edge + DynamoDB, replacing Algolia) and the Basket API (moving frontend logic to backend for multi-platform support), while championing documentation excellence and AWS cost optimization through monthly spend analysis and resource efficiency.

Skills & Technologies

Frontend

TypeScript React Next.js React Native

Backend

Node.js Express GraphQL Python

Cloud & Infrastructure

AWS AWS CDK CloudFormation Lambda S3

Databases

MongoDB PostgreSQL DynamoDB SQL

Tools & DevOps

Docker Git GitLab CI/CD Jest

Projects

Owning A Fender ecommerce platform
Owning A Fender

Built an ecommerce platform dedicated to Fender guitar enthusiasts. Features product listings, shopping cart functionality, and secure checkout for purchasing Fender guitars and accessories.

React Gatsby Shopify
Lift & Nourish mobile app
Lift & Nourish

Created a full-featured mobile app for fitness and nutrition, available on iOS and Android. Features personalized workouts, progress tracking, and healthy meal recipes to help users build strength and achieve their fitness goals.

React Native DynamoDB AWS Lambda AWS API Gateway AWS Cognito TypeScript
NPM Scan dashboard
NPM Scan

Developed an automated GitHub dependency security scanner that analyzes npm dependencies for vulnerabilities and outdated packages. Features health scores, multi-repository views, and smart AI prioritization to keep projects secure.

Next.js TypeScript MongoDB Vercel Stripe
Tech Lead App
Tech Lead App

Designed and built a comprehensive web application to help tech leaders manage teams, track progress, and streamline technical workflows. Built with modern web technologies.

React Node.js Express DynamoDB AWS Lambda AWS API Gateway AWS Cognito

Experience

Tech Lead at Dunelm
May 2024 - PRESENT
  • Lead a cross-functional team of 12 (6 engineers, 1 QA, 1 SDET, product manager, agile delivery lead, business analyst, UX designer) fostering an empowered, ownership-driven culture. Under my leadership, 2 engineers were promoted (graduate to junior in 1 year, associate to mid-level), and team velocity increased by over 20% in 6 months. Interviewed and onboarded 3 engineers in 18 months, creating extensive onboarding resources shared department-wide. Reinstated an on-call rotation to increase service ownership and engineer responsibility despite no budget allocation.
  • Architected and led the migration of Dunelm's Content Delivery Application from Algolia to an in-house solution using Fastly Compute@Edge and DynamoDB, now serving 100% of traffic with 0.0001% error rate, 35ms average latency, and 30 requests/second (75M/month). Worked closely with product managers, UX designers, and stakeholders to align technical architecture with business needs, improving Core Web Vitals and saving £350k annually in third-party costs.
  • Led the complete redesign of Dunelm's Basket API, implementing a multi-tenant GraphQL service that unified basket and delivery endpoints into a single query using AWS architecture with AWS CDK. This architectural decision reduced API calls by 50%, moved significant frontend logic to the backend enabling multi-platform support (web and mobile app), improved maintainability, and simplified third-party integrations.
  • Drive long-term technical strategy and engineering excellence across the team, championing documentation by maintaining up-to-date service documentation in Backstage and encouraging engineers to document backend systems as learning exercises. Champion AWS cost optimization through monthly spend dashboards tracking costs by service, empowering the team to be budget-aware and make data-driven efficiency improvements.
  • Co-founded Dunelm's Pipeline Guild alongside three other technical leaders to address CI/CD pipeline reliability and speed as a critical bottleneck. Led cross-team maintenance week sprints to align with CTO objectives: 90% pipeline success rate, sub-15 minute pipeline duration, tech debt reduction (removing old feature-flagged code), and security improvements (keeping packages up to date). Reduced front-end deployment time for 5 teams from 60+ minutes to 18 minutes and increased deployments by 50% through flaky test elimination and parallel execution optimization.
  • Recognized with Dunelm Technology's 2024 Mentorship Award for "making a significant impact by helping others unlock their potential and grow in their careers". Actively mentor 6 developers with tailored learning paths spanning AWS CDK, React, and soft skills, supporting individual growth while building a collaborative team culture praised by senior leadership for openness and high-quality delivery.
Full Stack Developer at Dunelm
Oct. 2021 - May 2024
  • Implemented a new credit solution in the existing backend, using event-driven architecture provisioned as infrastructure as code with AWS CDK and CloudFormation, along with assisting in architectural design. Ensured GDPR compliance for handling customer financial data and long-term credit storage.
  • Developed a novel front-end widget to sell Mattresses resulting in an uptick of 8.4% in revenue and 6.1% increase in average order value.
  • Maintained our in-store MPOS application that can be deployed to all stores using a Gitlab pipeline.
  • Key role in a squad put together to improve our Gitlab pipeline for our front-end code. The 2-week sprint resulted in our pipeline failure rate decreasing by 7.5% and duration going down from 25.5 minutes to 15.9 minutes.
Full Stack Developer at Valytica
Sep. 2020 - Oct. 2021
  • Designed and developed core full-stack products (React, Node.js, Postgres, GraphQL) for Valytica's clients, incorporating Jest for reliable integration tests.
  • Enhanced an existing Data Quality tool, transforming it into a full product. Focused on significant UI/UX improvements, leading to increased user satisfaction and efficiency in data comparison processes.
Senior Technical Operations Executive
Technical Operations Executive at Inflecto Media
Sep. 2019 - Dec. 2020
Dec. 2018 - Dec. 2019
  • Led the design and development of a full-stack business insights platform on AWS (EC2, S3, Athena, QuickSight), streamlining reporting processes and enabling a focus on long-term business strategies.
  • Pioneered a fraud detection initiative, using Python (Pandas, Matplotlib) for data manipulation and analysis, saving thousands in advertising costs through the identification and removal of fraudulent sources.
  • Conducted comprehensive training sessions for the wider team on technical topics, enhancing cross-departmental understanding and collaboration in areas like mobile advertising and fraud detection.

Education

MSci in Theoretical Physics - First Class
Sep. 2014 - Jun. 2018
Royal Holloway, University of London
  • Completed numerous programming projects and lab work using R, MatLab, Mathematica, and Python packages such as Numpy and Matplotlib to fit experimental data.
  • Created a GUI using Tkinter to demonstrate various principles of quantum mechanics, achieving 75% overall.

Certifications

Certified Agile Leader 1 certification badge

Certified Agile Leader® 1

Scaled Agile, Inc.

Focuses on modern agile leadership: empowering teams, outcome-driven delivery, and continuous improvement. Covers establishing vision and strategy, enabling autonomy with alignment, and creating psychologically safe, high-performance cultures.

Applied across cross-functional squads to improve flow, reduce dependencies, and mentor engineers through growth plans and technical enablement.

AWS Certified Cloud Practitioner certification badge

AWS Certified Cloud Practitioner

Amazon Web Services

Validates cloud fundamentals: AWS global infrastructure, shared responsibility model, cost optimization, security best practices, and foundational services (Compute, Storage, Networking, Databases).

Practical experience includes architecting low-latency, cost-efficient systems with IaC (AWS CDK), event-driven patterns, and observability at scale.

Read my exam preparation guide

Dunelm Technology Awards Jedi Master badge

Dunelm Technology Awards — Jedi Master

Dunelm Technology

Recognized for outstanding mentorship and leadership across engineering teams.

Developing Your Professional Skills certificate badge

Developing Your Professional Skills

Dunelm Technology

Awarded for creating the Lift & Nourish fitness app and championing personal development.

Awards & Recognition

2024 Mentorship Award
2024
Dunelm Technology
  • Awarded to "mentors who have made a significant impact by helping others unlock their potential and grow in their careers".
  • Recognized for actively mentoring 6 developers with tailored learning paths and technical projects, leading to the team's ticket velocity increasing by over 20% over 6 months.

Technical Writing

Interests

Powerlifting

Passionate about powerlifting and strength training. Have competed twice in powerlifting competitions, focusing on continuous improvement and pushing personal limits.

Contact me

Get in touch or send me a message

Or email me directly at nickolastheodoulou@hotmail.com