Jimmie Aaron Butler, Developer in Zagreb, Croatia
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Jimmie Aaron Butler

Verified Expert  in Engineering

DevOps Engineer and Developer

Zagreb, Croatia
Toptal Member Since
January 3, 2021

Jimmie has deep expertise in developing back-end services in Go and managing and automating infrastructure with IaC. He specializes in Go, Google Cloud, Kubernetes, and Terraform. He has used these for over five years to build back-end services and CI/CD pipelines and improve automation. In one of Jimmie's most exciting projects, he developed cloud infrastructure for a central eCommerce platform that serves students at more than 900 college campuses.


OpenAI, Large Language Models (LLMs), Prompt Engineering, React, Node.js...
Go, REST, MySQL, Swagger, Google Cloud, Docker, Back-end, OpenAPI...
On Campus Marketing
DevOps, Linux, Google Cloud Platform (GCP), Infrastructure as Code (IaC), React...




Preferred Environment

Google Cloud, Kubernetes, Terraform, Go, React, ChatGPT

The most amazing...

...project I've worked on was a legal LLM (Inkly), targeted at minimizing hallucination via a RAG pipeline.

Work Experience

Lead Developer

2022 - 2024
  • Transitioned the tech stack through three pivots, from a redlines/contract negotiation tool to a real-time sales workspace similar to Notion to a legal large language model (LLM), minimizing hallucination and providing high-quality answers.
  • Led the design of all aspects of the tech stack, from infrastructure, front end, back end, and machine learning (ML) strategy (except UI designs).
  • Collaborated successfully with a remote distributed team across multiple time zones, using Jira, Slack, and Loom.
Technologies: OpenAI, Large Language Models (LLMs), Prompt Engineering, React, Node.js, TypeScript, Firebase, Cloud Firestore, Google Cloud, GitHub Actions, Next.js, Pinecone, Material UI

Back-end Developer

2021 - 2022
  • Refactored testing and test data for readability and usability. Created a helper library to define data required for a test declaratively, add it to the database, and clean it up afterward.
  • Designed and implemented a generation of zip files for user download.
  • Redesigned and rolled out access control changes to work with organizational feature requirements and the addition of the organization's related APIs.
Technologies: Go, REST, MySQL, Swagger, Google Cloud, Docker, Back-end, OpenAPI, Back-end Development, Jira, Remote Work, Web Architecture, SQL, REST APIs, APIs

DevOps and Full-stack Developer

2019 - 2021
On Campus Marketing
  • Diagnosed issues causing bloated bundle size and reduced react app bundle size by 75%.
  • Improved lighthouse score by 50+ for desktop load times through caching and front-end optimization.
  • Organized the GitLab CI/CD for deploying microservices and infrastructure changes.
  • Created Terraform scripts to manage infrastructure as code (IaC).
  • Designed, set up, and managed a per-branch UI preview, allowing QA to go through a branch with front-end changes before merging to a staging environment.
  • Provided actionable insights about performance issues with the browser SPA and did some development to implement fixes in this area.
  • Managed and set up monitoring and alerts to quickly flag issues affecting customers.
  • Implemented OCM's caching strategy. At its core, requests to the server never include user data, which works well for this project and allows CDN to store all results returned from the back-end until code or data changes.
  • Observed and fixed several memory leaks in the react application.
Technologies: DevOps, Linux, Google Cloud Platform (GCP), Infrastructure as Code (IaC), React, Next.js, GitLab CI/CD, Website Performance, Docker, Go, Terraform, Google Kubernetes Engine (GKE), Kubernetes, Cloud, CI/CD Pipelines, GraphQL, Elasticsearch, Identity & Access Management (IAM), Content Delivery Networks (CDN), Redis, Full-stack, JSON Web Tokens (JWT), Node.js, Back-end Development, Amazon Web Services (AWS), Jira, Remote Work, Web Architecture, Microservices, Google Cloud, Continuous Integration (CI), Helm, Full-stack Development, APIs, REST APIs, Distributed Systems

Co-founder and Lead Developer | DevOps

2017 - 2018
UTU Intelligence
  • Designed and built a pipeline for ingesting high volumes of user data.
  • Managed a production Kubernetes cluster with Terraform. This was the infrastructure behind all the company's development resources.
  • Forked and maintained the community Terraform provider for Kubernetes to include pod anti-affinity to support our database hosting.
Technologies: Docker, Linux, Google Cloud Platform (GCP), DevOps, CircleCI, Kubernetes, Google Kubernetes Engine (GKE), Terraform, Go, CI/CD Pipelines, Cloud, BigQuery, MongoDB, Google Pub/Sub, Identity & Access Management (IAM), Back-end, Back-end Development, Jira, Remote Work, Web Architecture, Microservices, Continuous Integration (CI), Helm, NoSQL, React, JavaScript, APIs, REST APIs, Distributed Systems

Freelance Full-stack Developer

2015 - 2016
  • Developed an application similar to Pinterest with a focus on affiliate marketing.
  • Built an application for internal inventory management. An initial version was done in less than a day, on time, and under budget.
  • Maintained and upgraded an application for a medical research lab that worked with patient data.
Technologies: Meteor, MongoDB, JavaScript, CSS, HTML, React, NoSQL

React Visual Editor

Developed a website designer that exports pixel-perfect React code every time. Drag and drop React components were implemented using the MUI design system.

It's a design tool that works seamlessly with your development processes and eliminates integration work. I'm the only person working on this product, so I wear all the hats.

ML Research

The research focused on generative design without an input dataset.

Attempt to generate interesting floor plans, schematic layouts, and efficient box packing.

Built graph neural networks, fully differentiable loss functions, investigating non-gradient descent-based deep learning.

Technical Blog

A technical blog on various topics, including Terraform, machine learning, Go, and Kubernetes.

Some highlights include:
• Setting up Kubernetes zero-downtime deployments with testing.
• Zero loss on the fly expansion of linear layers deep learning.
• Additional posts around deep learning research I've been working on.

Terraform Associate



Deep Learning Nanodegree



Node.js, React, PyTorch, OpenAPI, TensorFlow, REST APIs


Terraform, Google Kubernetes Engine (GKE), GitLab CI/CD, CircleCI, ChatGPT, Jira, Helm, BigQuery


Go, TypeScript, GraphQL, SQL, Julia, Rust, Python, JavaScript, CSS, HTML


Kubernetes, Docker, Google Cloud Platform (GCP), Linux, Amazon Web Services (AWS), Firebase, Meteor


DevOps, Microservices, Continuous Integration (CI), Web Architecture, REST, Testing


Google Cloud, Elasticsearch, Amazon S3 (AWS S3), MongoDB, Redis, MySQL, Cloud Firestore, NoSQL


Material UI, Next.js, Swagger, JSON Web Tokens (JWT)


Cloud, Back-end Development, Full-stack Development, CI/CD Pipelines, Identity & Access Management (IAM), Back-end, OpenAI, Website Performance, GitHub Actions, Deep Learning, Machine Learning, Remote Work, Infrastructure as Code (IaC), Google Pub/Sub, Content Delivery Networks (CDN), Full-stack, Code Generators, APIs, Distributed Systems, Large Language Models (LLMs), Prompt Engineering, Pinecone

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