David West, Developer in Dublin, Ireland
David is available for hire
Hire David

David West

Verified Expert  in Engineering

Software Developer

Dublin, Ireland
Toptal Member Since
April 20, 2016

David is a skilled Kotlin/Java, native mobile, Flutter, and React web developer with the ability to build web-scale, high-performance full-stack systems ahead of schedule. He's the type of developer who quickly gains expertise in any tech. David's focus is on Java microservice back-end applications and he has a passion for building native iOS and Android mobile apps. David is comfortable working in US or European time zones.


React, JavaScript, AWS SDK, AWS Lambda, Amazon DynamoDB, Elasticsearch, GraphQL...
Quorilla (Toptal Projects)
Kotlin, Spring Boot, React, Amazon Web Services (AWS), AWS Lambda, AWS Fargate...
FreeRoots (Toptal Projects)
Amazon Web Services (AWS), Docker, Kotlin, GraphQL, Redux, React, HTML5, CSS3...




Preferred Environment

Git, Xcode, Eclipse, IntelliJ IDEA, MacOS

The most amazing...

...feeling of accomplishment was having my first iOS app featured on the App Store, going from zero iOS experience to a first released version in just two weeks.

Work Experience

Full-stack React/AWS Developer

2021 - 2022
  • Developed client-facing features to allow users to manage their accounts and guide their progress on Capterra.com.
  • Built a React front-end application using a micro front-end architecture, communicating with the back end via a GraphQL API (AWS AppSync). Aided the team in adopting GraphQL best practices.
  • Developed back-end AWS Lambda functions (using JavaScript) for the website, using DynamoDB and Elasticsearch as data stores. Integrated with Kafka topics to populate the data sources.
Technologies: React, JavaScript, AWS SDK, AWS Lambda, Amazon DynamoDB, Elasticsearch, GraphQL, AWS AppSync, Apache Kafka, HTML5, CSS3, JavaScript 6, Architecture, Full-stack Development

Lead Developer

2020 - 2020
Quorilla (Toptal Projects)
  • Was selected by Toptal Projects for a two-week lightning start to plan and estimate the MVP as the lead developer, along with the lead designer and the project and delivery managers. Led a team of five developers in the implementation phase.
  • Built the front end using React, Redux, MUI (Material UI), and WebRTC/HLS live video streaming.
  • Built the back end using Kotlin Spring Boot microservices and Node.js AWS Lambda functions for live-streaming video processing. These loosely coupled microservices communicated using event-based communication with AWS SQS queues.
  • Deployed dockerized microservices using AWS Fargate, Node.js serverless processing for video processing using AWS Lambda, AWS Media Services APIs, and continuous delivery with CircleCI.
  • Included a full-text search of courses, classes, and tutors using Elasticsearch and Hibernate Search.
  • Led the team to build the MVP of the project from the planning stages to completion in four months within time and budget.
Technologies: Kotlin, Spring Boot, React, Amazon Web Services (AWS), AWS Lambda, AWS Fargate, Node.js, HTML5, CSS3, JavaScript 6, Architecture, Full-stack Development, Technical Leadership

Lead Developer

2018 - 2019
FreeRoots (Toptal Projects)
  • Was selected by Toptal Projects for a two-week lightning start to plan and estimate the MVP as the lead developer, along with the lead designer and the project and delivery managers. Led a team of four developers in the implementation phase.
  • Built a React/Redux front-end application using functional React components and hooks.
  • Used an Apollo GraphQL library to communicate with the microservices back end.
  • Built the back end using Kotlin Spring Boot microservices. These loosely coupled microservices communicated using event-based communication with AWS SQS queues.
  • Deployed dockerized microservices using AWS Fargate and continuous delivery with CircleCI.
  • Led a team of four developers to deliver the MVP in four months, within time and budget.
Technologies: Amazon Web Services (AWS), Docker, Kotlin, GraphQL, Redux, React, HTML5, CSS3, JavaScript 6, Architecture, Full-stack Development, Technical Leadership

Lead Developer

2018 - 2018
Other Clients (Toptal Projects)
  • Was selected by Toptal Projects for two other lightning start projects to plan and estimate them as a lead developer. Led a team of two developers in the implementation phase.
  • Built two sharing economy native apps: a native iOS app using Swift and a native Android app using Kotlin.
  • Implemented communication via REST with Spring Boot microservices written in Kotlin.
  • Deployed dockerized containers on AWS Fargate.
  • Implemented payment processing via Stripe.
  • Built an admin portal using React/Redux.
  • Delivered the apps on time and within budget.
Technologies: Amazon Web Services (AWS), Docker, Spring Boot, Kotlin, Android, Swift, iOS, HTML5, CSS3, JavaScript 6, Architecture, Full-stack Development, Technical Leadership

Technical Architect

2010 - 2018
  • Designed the architecture and implemented a web­-scale, multi­-tenant cloud-based platform for the beauty industry with Java and open source stack with microservice architecture.
  • Developed a multitenant cloud system that services thousands of businesses with millions of customers, built on elastic, scaling AWS cloud infrastructure using Amazon ECS and Docker.
  • Developed Spring Boot microservice applications deployed on AWS ECS; built with Java, Groovy, and Kotlin.
  • Built Objective-C and Swift iOS apps. One iOS app was featured by Apple in the App Store.
  • Developed native Android apps using Java and Kotlin.
  • Built web apps using the JavaScript framework Ember.js.
Technologies: Amazon Web Services (AWS), Kotlin, Groovy, Java, NoSQL, Hibernate, Spring, Docker, Microservices, Android, iOS, Ember.js, HTML5, CSS3, Architecture, Full-stack Development

JEE Architect (Contractor)

2010 - 2010
  • Acted as a Fujitsu consultant onsite at the Irish tax authority (revenue commissioners).
  • Developed a new ESB solution for revenue as part of their SOA strategy, in addition to Java development on other projects.
  • Used the Mule ESB to mediate JMS, web services, and legacy communication protocols between the revenue’s web applications and back-­end core tax processing services.
  • Defined the XA transaction strategy for integrating the various endpoints.
  • Worked on various other JEE applications using WebLogic, Sprint, Hibernate, and Ingres.
Technologies: Hibernate, Spring, Ingres, WebLogic, Java, Architecture, Full-stack Development

Solutions Architect (Contractor)

2008 - 2009
Sentenial Software
  • Designed and built a B2B core integration framework for SEPA’s high-volume message-­based, direct debit payment processing.
  • Developed a specific implementation for integrating Sentenial's SEPA payment system with the accounting systems of the Royal Bank of Scotland.
  • Designed a flexible integration framework which allows Sentenial’s suite of products to stream messages to heterogenous bank systems via web services, JMS, SFTP, files, etc, through a configuration of different endpoints.
  • Used Spring (including Spring Web Services and Spring Batch), various XML processing frameworks (DOM, SAX, XSLT, XPath, JAXB, XSD), JMS, WebSphere, JBoss, Oracle and DB2 on Windows, Linux, and ZOS mainframes. The system is currently being used to process payments in Royal Bank of Scotland and ABN Amro.
Technologies: IBM Db2, Spring Batch, Spring, IBM z/OS, Linux, Oracle, JBoss, WebSphere, JMS, XSD, JAXB, XPath, XSLT, SAX, DOM, Architecture, Full-stack Development

Senior Software Engineer

2007 - 2008
Cusp Point Software
  • Worked as the lead developer, mainly designing and delivering a large number of features in a highly distributed, multi­-tenant web application, targeted at terabytes of data in a SAS document management system.
  • Built an Ajax front­ end, back­ end, and did full-­stack development for the core document management web application using a JBoss Application Server, Seam, Spring, and JPA architecture.
  • Developed a SOAP/REST document management web service.
  • Created a back-­end domain ­object based security framework for a multi-­tenant web application using Spring Security.
  • Wrote a document ­routing workflow web application using JBoss JBPM, and a document batch processing engine using Spring/Hibernate.
Technologies: BPM, JBoss, RESTful Web Services, SOAP, JPA, Spring, Seam, JBoss Application Server, Full-stack Development, Application Servers

Senior Software Engineer (Contractor)

2006 - 2007
  • Contributed to the build of an embedded platform for Corvil’s network bandwidth quality manager, to support introspection of network problems in high-volume, financial trading environments using statistical algorithms to analyze 10 GB packet rates to microsecond accuracy.
  • Managed and worked in core Java development.
  • Wrote network systems programming C, C++, and Python and did Bash integration testing on a Linux platform running PostgreSQL.
  • Profiled and performance tuned Java and PostgreSQL.
Technologies: Java, Bash Script, Python, PostgreSQL, C, C++, Full-stack Development

Software Engineer (Contractor)

2005 - 2006
  • Developed a new web­services SOA, using J2EE technologies, supporting AOL’s internal and B2B strategy.
  • Helped design and build the Order Management Service; used a range of technologies and techniques, including web services (via WebLogic), Hibernate, Spring, Drools, Tapestry, Maven, and model-driven architecture (using AndroMDA).
  • Used standard Jakarta EE technologies such as EJB, JMS, and servlets.
Technologies: Apache Maven, Tapestry, JBoss Drools, Spring, Hibernate, WebLogic, Full-stack Development

Research Associate

2003 - 2005
University of Sydney | NICTA
  • Worked on two industry ­funded research and development projects.
  • Was involved in developing a Bluetooth/GSM telecommunications hybrid-positioning system (Symbian/C++ and J2ME).
  • Worked with heterogeneous middleware for multi-modal input and output (Java, C++).
  • Was published in seven journal and conference publications.
Technologies: J2ME, Symbian, C++, C#, Java

Technology Analyst (Intern)

2002 - 2002
Barclays Capital Investment Bank, New York
  • Developed applications for managing the corporation's Sybase database users using Visual Basic; my work increased the application performance by over an order of magnitude.
Technologies: Sybase, Visual Basic


1999 - 2001
Genie Internet Consultancy
  • Worked on web ­application development using PHP, Perl, MySQL, JavaScript, and DHTML.
Technologies: DHTML, JavaScript, MySQL, Perl, PHP

Live Video Streaming React Web App and Back End

Quorilla.com is a live video streaming website in the education sector. The MVP of the project was built in four months.

The functionality includes:
• Setting up courses and classes
• Onboarding tutors and students
• Email communications
• In-browser live streaming for the tutor using WebRTC technologies
• In-browser viewing of classes (live and recorded)
• Video processing server side to convert live classes into recorded videos available on demand

React Web App for Grassroots Political Advocacy

Freeroots.com is a website enabling ordinary citizens to create free grassroots political campaigns. (temporarily offline while the company rebrands).

The MVP was built in four months, and the app uses React, Redux, GraphQL, and Firebase on the front end and Spring Boot, microservices, Kotlin, and AWS on the back end.

• Campaign creation and display
• Bulk emails with client filters
• Client management
• Bulk CSV uploads
• Analytics
• Stripe Connect payments
• Admin portal
• Integration with complex APIs for contacting US senators and representatives
• Social sign in

Podcast Demo App Built with Flutter

I built this demo app using Flutter for iOS and Android — see a screen recording in the video above.

Scheduling and Point of Sale Application | Native iOS and Native Android

This app is very popular with its tens of thousands of business users. It provides appointment scheduling (with my own calendar component), point-of-sale, reporting, staff scheduling and much more. I can demo it on request; it's available in both the Google Play Store and Apple App Store.

• https://itunes.apple.com/ie/app/phorest-go/id623199514?mt=8

• https://play.google.com/store/apps/details?id=com.phorest.phorestgo
2002 - 2003

Master of Science Degree in Computer Science: Networks and Distributed Systems

Trinity College Dublin, the University of Dublin - Dublin, Ireland

1998 - 2002

Bachelor's Degree in Computer Science

Trinity College Dublin, the University of Dublin - Dublin, Ireland


REST APIs, SAX, JMS, React, AMQP, Alamofire, CocoaPods, JAXB, Facebook API, Node.js, WebRTC


ActiveMQ, Eclipse IDE, IntelliJ IDEA, Xcode, RabbitMQ, Android Studio, AWS SDK, Amazon Simple Queue Service (SQS), JBoss Drools, TestFlight, GitHub, Git, JBoss Application Server, Apache Maven, Cucumber, AWS Fargate, AWS AppSync, Application Servers


Flutter, JPA, Spring Boot, Spring JDBC, Hibernate, Spring, UIKit, Cocoa Touch, Cocoa, TestNG, JUnit, Redux, Google Guava, jBPM, Spring MVC, Spring Batch, Seam, Tapestry, Ember.js


Kotlin, Groovy, Swift, Java, Objective-C, XML, SQL, GraphQL, JavaScript, HTML, HTML5, CSS3, JavaScript 6, C++, C, XPath, TypeScript, XSLT, XSD, Python, C#, Visual Basic, PHP, Perl, Dart, Bash Script


Microservices, Microservices Architecture, Scrum, REST, Testing, Acceptance Testing, Unit Testing, Kanban, Agile Software Development


JEE, iOS, Android, Docker, Amazon Web Services (AWS), Oracle, Amazon EC2, Windows, JBoss, MacOS, Linux, Eclipse, WebSphere, IBM z/OS, Symbian, J2ME, AWS Lambda, Apache Kafka


JSON, MySQL, PostgreSQL, Spring Data, Amazon S3 (AWS S3), Memcached, AWS SWF, IBM Db2, Microsoft SQL Server, Sybase, Ingres, NoSQL, Amazon DynamoDB, Elasticsearch


Apache Commons, DOM, Full-stack, RESTful Web Services, Integration Testing, APIs, Back-end, Architecture, Full-stack Development, Technical Leadership, WebLogic, GitFlow, SOAP, BPM, DHTML, HTTP Live Streaming (HLS)

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.


Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring