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I’m a senior back end engineer with 10+ years’ experience designing secure, distributed systems in production. I specialise in building and operating back end services where correctness, integrity, and trust boundaries matter — including authentication, message signing, replay protection, and secure key handling. My work spans applied cryptography, domain-driven back end architecture, and high-throughput APIs supporting payments, scheduling, and multi-country data processing.…I’m a senior back end engineer with 10+ years’ experience designing secure, distributed systems in production. I specialise in building and operating back end services where correctness, integrity, and trust boundaries matter — including authentication, message signing, replay protection, and secure key handling. My work spans applied cryptography, domain-driven back end architecture, and high-throughput APIs supporting payments, scheduling, and multi-country data processing.

Andrew Cookson

Back-End Developer, Full Stack Developer, Web Developer, +2

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I’m a senior back end engineer with 10+ years’ experience designing secure, distributed systems in production. I specialise in building and operating back end services where correctness, integrity, and trust boundaries matter — including authentication, message signing, replay protection, and secure key handling. My work spans applied cryptography, domain-driven back end architecture, and high-throughput APIs supporting payments, scheduling, and multi-country data processing.…I’m a senior back end engineer with 10+ years’ experience designing secure, distributed systems in production. I specialise in building and operating back end services where correctness, integrity, and trust boundaries matter — including authentication, message signing, replay protection, and secure key handling. My work spans applied cryptography, domain-driven back end architecture, and high-throughput APIs supporting payments, scheduling, and multi-country data processing.

Available to hire

I’m a senior back end engineer with 10+ years’ experience designing secure, distributed systems in production. I specialise in building and operating back end services where correctness, integrity, and trust boundaries matter — including authentication, message signing, replay protection, and secure key handling.

My work spans applied cryptography, domain-driven back end architecture, and high-throughput APIs supporting payments, scheduling, and multi-country data processing.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Language

English

Fluent

Work Experience

Senior Back End Engineer at Delivery App

November 1, 2024 - Present

Senior back end engineer specializing in large-scale logistic platforms. I build and maintain Laravel-based micro-services that handle order scheduling, driver operations, payments, and multi-country address intelligence. I own critical business logic such as credit-check windows, scheduling workflows, and driver eligibility, and deliver production-grade APIs backed by automated tests, CI pipelines, and containerised infrastructure. Implemented HMAC-based service-to-service authentication for internal APIs, including canonical request signing, replay protection, key rotation, and constant-time verification. Designed secure secret management, observability, and admin tooling, and shipped via feature-flagged rollout in a production micro-services environment.

Full-stack Developer at Nexus Vehicle Rental

March 1, 2023 - November 30, 2024

Led refactoring of a legacy procedural PHP code-base to object-oriented architecture using domain-driven design principles. Designed DDD-style domain models, controllers, and service classes to represent real-world vehicle rental entities and workflows. Restructured application layers to improve separation of concerns, testability, and long-term maintainability. Worked extensively with large MySQL schemas and queries across multi-million-row datasets, optimising performance and reliability. Integrated scheduled processes and external APIs to support operational data flows. Collaborated within agile sprint cycles with product and QA stakeholders.

Back End PHP Engineer at Tribus

August 1, 2021 - March 31, 2023

Refactored legacy PHP applications by upgrading from PHP 5 to PHP 8, ensuring smooth functionality and compatibility with modern standards. Migrated a WordPress plugin from SOAP to REST using Guzzle, successfully modernising the plugin’s API communication without introducing bugs. Converted YamlDriver to Doctrine annotations, enhancing code readability and maintainability. Migrated a legacy Pat template system to Twig, refactoring controllers and templates to improve front-end flexibility and scalability. Extended a REST API in Symfony (API Platform) for an Android app, ensuring seamless integration with the front-end.

Backend Developer at OnBuy

March 1, 2021 - August 31, 2021

Developed administrative tools and reports for a large e-commerce platform, handling CRUD operations on buyers, sellers, and products. Worked with MySQL to efficiently query large datasets and used Docker for containerized local development environments. Integrated technologies like Couchbase, RabbitMQ, and Redis to ensure smooth and reliable data handling and real-time communication between services. Collaborated in an agile environment with daily stand-ups and code reviews, optimising back-end processes for performance and scalability.

Back-end Developer at Intellicentrics

May 1, 2019 - March 31, 2021

Developed and maintained back-end services for healthcare software, focusing on staff management systems for hospitals in the UK and US. Contributed to micro-services architecture by developing APIs to integrate various systems within the platform. Collaborated in agile teams, participating in daily stand-ups, sprints, and code reviews, taking ownership of user stories through the development life cycle. Used Docker for efficient development and deployment of containerized applications, improving scalability. Contributed to automated testing with Jenkins, ensuring reliable and repeatable deployments.

Full-stack Developer at MLP

October 1, 2017 - May 31, 2019

Developed and launched marketing campaigns for major brands like AA and Enterprise. Utilised the Laravel framework for building both front-end and back-end features, including user authentication, routing, and middle-ware. Leveraged Laravel’s Eloquent ORM to manage and query relational databases, improving database performance and accessibility. Developed custom micro-sites, ensuring responsiveness and consistency with parent websites.

Front-end Developer at First Internet

August 1, 2015 - October 31, 2017

Built custom WordPress themes using Bootstrap and the Underscores framework, collaborating closely with designers to optimise UI/UX. Focused on responsive design, ensuring websites performed well across devices. Utilised WP Query for complex meta and taxonomy queries directly to the database, improving data handling on the front-end.

Back-end Developer at CDL

September 1, 2014 - August 31, 2015

Maintained and enhanced the My Car Check service, a vehicle lookup tool providing detailed reports on vehicle history. Worked with PHP, Linux, Apache, and XML to ensure accurate data delivery across various platforms, including JSON and XML web services.