Jonathan Haygood, Developer in Berlin, Germany
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Jonathan Haygood

Verified Expert  in Engineering

Data Engineer and Software Developer

Berlin, Germany
Toptal Member Since
January 10, 2022

Jonathan has 11+ years of experience in software and data engineering. He has worked on E2E systems for enterprise companies and start-ups, building consumer-facing and B2B applications. Ranging from media, fintech, eCommerce, SaaS, and marketing industries. He helps teams build confidence in their technologies by designing API integrations, back-end systems, cloud infrastructure (AWS), front-end (web) applications, databases, and big data prediction models.


Amazon Web Services (AWS)
JavaScript, TypeScript, Java, Scala, Node.js, AWS Lambda, Amazon DynamoDB...
Scala, Ruby, React, Spark, Spark ML, Redis, Amazon S3 (AWS S3)...
Time Inc
JavaScript, Go, Clojure, ClojureScript, Recommendation Systems, Python, C++...




Preferred Environment

Amazon Web Services (AWS), Web

The most amazing...

...project I've designed, architected, and developed was ad infrastructure for a media company that grossed $50+ million.

Work Experience

Senior Software Engineer

2019 - PRESENT
Amazon Web Services (AWS)
  • Led security assessments for 6+ major projects from design consulting to penetration testing and compliance, providing vital vulnerability remediation for projects managing billions of transactions per second.
  • Directed internal project to scale system to support 5x current capacity and remove performance bottlenecks, eliminating months of manual effort.
  • Designed complete rewrites of systems that included rearchitecting APIs from monolithic servers to microservices on AWS cloud, database reconfiguration, migrations from legacy Angular code into React, and managed project security compliance.
  • Managed a team of 4+ engineers, overseeing hiring, onboarding schedules, team integration, career development, and promotion paths.
Technologies: JavaScript, TypeScript, Java, Scala, Node.js, AWS Lambda, Amazon DynamoDB, Amazon EC2, Redux, Amazon Web Services (AWS), Full-stack, Architecture, Functional Programming, APIs

Senior Data Engineer

2018 - 2019
  • Cut ETL pipeline runtime in half, parallelizing cloud computing workflows while decreasing AWS spend.
  • Optimized statistical and machine learning models by converting from R libraries to Spark (Scala) and designed modeling around new KPIs.
  • Performance-tested and improved a back-end API for dashboard app speed and efficiency, reconfiguring the caching layer (Redis, S3, Spark).
  • Led an initiative (produced mockups, created a POC, load-tested, etc.) to investigate the migration from Rails to Phoenix (Elixir). The outcome was positive and would have been pursued, but a Clojure-heavy firm shortly acquired the company.
Technologies: Scala, Ruby, React, Spark, Spark ML, Redis, Amazon S3 (AWS S3), Amazon Elastic MapReduce (EMR), Amazon Web Services (AWS), Architecture, ClojureScript, Clojure, Functional Programming, APIs, Elixir, Phoenix

Senior Software Engineer

2016 - 2018
Time Inc
  • Launched a team of five on ad infrastructure projects (Python, C++, JavaScript), scheduled to gross $50+ million yearly.
  • Composed recommendation system projects (Spark, AWS) that manage. 25-50 million daily unique data points.
  • Revamped outdated monolithic structure with new Python, Clojure, Go, and Node.js microservices utilizing AWS, Lambda, S3, EC2s, API Gateway, etc.
Technologies: JavaScript, Go, Clojure, ClojureScript, Recommendation Systems, Python, C++, Spark, Redux, Amazon Web Services (AWS), Full-stack, Architecture, Vue, Functional Programming, APIs

Software Engineer

2015 - 2016
  • Architected API for all new technology stack: Java, ES6, React, MDX, and JSON (used to write an MDX parser from scratch).
  • Developed a component library (React) for data analytics platform dashboarding system.
  • Directed an international training conference to expose API to the consulting team.
Technologies: JavaScript, TypeScript, React, Node.js, Java, Redux, Full-stack, Functional Programming, APIs

Software Engineer and Data Analyst

2012 - 2015
Whitelaw & Co.
  • Established project management process that removed the $100,000 cost from each major project.
  • Built a UI (AngularJS) proof-of-concept to demonstrate product at client meetings.
  • Engineered MS Excel, VBA, C++ solutions with Sawtooth Software for conjoint analysis to forecast market strategies.
Technologies: JavaScript, Financial Modeling, AngularJS, Full-stack

Controls Engineer

2010 - 2011
  • Worked locally on more than twelve different conveyor belt system projects for major airports in Mexico, Kalamazoo, and Sacramento.
  • Assisted in designing SCADA/HMI using Factory Talk for projects in Mexico and San Antonio. Spent two weeks in San Antonio to help implement and test interfaces.
  • Built tools in VBA, JavaScript, C++ to organize and operate on quantitative data.
Technologies: JavaScript, C++

Data Visualization for Insights Platform
The platform uncovers and displays sentiment analysis gauging themes and the magnitude of reactions of the audience. I consulted on the project, rewriting much of the charting library to be more optimally integrated with D3.js animations and transitions.

Financial Budgeting App

A Node.js and React app that allows users to track monthly spending and income. Users can enter data manually or integrate via plaid ( to their financial institutions.

The dashboards displayed monthly information with a calendar view and allowed data to be categorically tracked and targeted (goal setting) based on previous behavior from the user.

I worked with the founder to build out the prototype to gain funding, where she was accepted into an accelerator program to build marketability for the application.
2017 - 2019

Master's Degree in Computer Science

New York University - New York, New York, USA

2008 - 2012

Bachelor's Degree in Mathematics

University of Georgia - Athens, Georgia, USA


Node.js, React, D3.js, Spark ML, Vue


Git, Amazon Elastic MapReduce (EMR)


Redux, AngularJS, Phoenix, Spark, ClojureScript, NestJS


JavaScript, TypeScript, Java, Scala, Python, Elixir, Erlang, Haskell, Clojure, Ruby, Go, C++


Functional Programming


Web, AWS Lambda, Amazon EC2, Amazon Web Services (AWS)


Amazon S3 (AWS S3), Amazon DynamoDB, Redis


Full-stack, APIs, Application Security, Machine Learning, Architecture, Recommendation Systems, Financial Modeling

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