

Arjaan Buijk
Verified Expert in Engineering
Machine Learning Developer
Plymouth, MI, United States
Toptal member since June 4, 2018
Arjaan is co-founder of onicai (onicai.com). He's an open-source developer and AI/LLM expert with deep experience in DevOps (AWS and Terraform), crypto (especially Internet Computer Protocol), Python web frameworks (Django and FastAPI), machine learning, and data science. He created icpp-pro, a C++ smart contract framework for the Internet Computer with over 74,000 downloads. A committed lifelong learner, Arjaan enjoys opportunities to collaborate on innovative and challenging projects.
Portfolio
Experience
- Python - 10 years
- C++ - 10 years
- Artificial Intelligence (AI) - 6 years
- Machine Learning - 4 years
- Open-source LLMs - 3 years
- llama.cpp - 3 years
- Agentic AI - 2 years
- Claude - 1 year
Preferred Environment
Python, C++20, llama.cpp, Django, Motoko, Terraform
The most amazing...
...AI agents I've built run llama.cpp on the Internet Computer Protocol.
Work Experience
Co-founder | CTO
onicai LLC
- Built fully on-chain AI agents powered by the Internet Computer Protocol, integrated into multiple applications with a combined market capitalization of several hundred thousand dollars.
- Designed and developed the open source Python and C++ tooling enabling open source LLMs to run on the Internet Computer Protocol using llama.cpp (65,000 downloads).
- Guided the launch process of funnai.onicai.com. I wrote several Python utilities to monitor AI agents' status and to track application metrics.
Customer Success Engineering Manager/Director
Rasa
- Led technical engagements with enterprise clients at Rasa, a leading conversational AI platform.
- Acted as a trusted technical advisor, helping clients architect, build, and optimize AI-powered virtual assistants using Python and Rasa's NLP/ML framework.
- Collaborated closely with product and engineering teams to align roadmap with client needs.
Senior Software Engineer
US-based SaaS Company
- Improved developer productivity by reducing local development set up from two days to one hour. Created a dockerized development environment for a SaaS application consisting of Django, Go, and React.
- Created detailed wiki pages in Confluence with instructions for using the dockerized development environment and the API-testing framework. Worked with the development team to implement the new tools and improve their workflows.
- Created an API-testing framework using Postman and Newman. REST APIs are served by Django, and GraphQL APIs are served by Go. The tests run automatically as part of CI/CD workflows with CircleCI and Bitbucket.
Solutions Engineer (NLP)
Rasa
- Supported large enterprise customers by implementing and deploying mission-critical chatbots built with Rasa. Deployments use Docker, Docker Compose, Kubernetes, and OpenShift. Infrastructure a combination of on-prem, AWS, GCP, and Azure.
- Designed and implemented NLU data, dialog stories, rules, forms, and custom actions (Python) for industry-relevant demonstrator chatbots.
- Extended Rasa Open Source (Python) available at https://github.com/rasaHQ/rasa. This is an open-source machine learning framework to automate text- and voice-based conversations: NLU, dialogue management, connect to Slack, Facebook, and more.
- Created and taught an online course on advanced deployment techniques with Kubernetes (https://www.udemy.com/course/rasa-advanced-deployment-workshop/).
- Implemented Python Asyncio in back-end APIs resulting in dramatically improved throughput rates.
- Created CI/CD pipeline that trains a Rasa bot, builds a custom docker image, stores the artifacts in AWS S3 and AWS ECR, automatically creates an AWS EKS cluster using the eksctl CLI, deploys Rasa with Helm, and Smoke Tests using Python.
Freelance Data Scientist
University of Colorado Boulder
- Developed a sequence-based machine learning model in Python using TensorFlow to predict university student application probability based on millions of time-stamped engagements.
- Developed a clustering logic in Python using Scikit-Learn to group students by engagement behaviors.
- Built a decision tree model in Python using XGBoost to predict the probability for admitted students to enroll (yield).
Software Engineer
MSC Software
- Developed a finite element and finite volume simulation software in Python, C++, and Fortran.
- Designed and implemented a desktop application front-end with the Microsoft Foundation Class Library (MFC) and Qt.
- Performed pre-sales demonstrations, customer training and support, sales, and business development.
- Managed a team of solver developers. I was responsible for the definition and execution of projects, yearly employee reviews, and career planning of the direct reports.
Founder | Owner
Simufact-Americas, LLC
- Founded a company for the resale of manufacturing simulation software that I co-developed.
- Achieved a 20-fold increase in revenue for the Americas region.
- Used Python and web development to automate business processes.
- Created pre-sales, sales, and post-sales onboarding processes.
Experience
Platform Engineer | Healthcare Data Management
https://onoshealth.com/Key focus areas: Infrastructure-as-code, observability systems, and security-first cloud architecture.
funnAI
icpp-pro: C++ Platform for the Internet Computer
It has 65,000 downloads from PyPI.
Llama.cpp for the Internet Computer
https://github.com/onicai/llama_cpp_canisterStudent Application Prediction
The data pipeline extracted millions of records from several SQL databases and generated features for the machine learning model. The end result of the data pipeline was a pandas DataFrame written to an S3 bucket. The machine learning pipeline loaded the pandas DataFrame and trained a custom TensorFlow model used by the university admissions department to identify the most promising prospective applicants.
Chatbot for an Expert System
The chatbot provides an alternative interface to a web-based expert system. The data pipeline creates word and sentence embeddings from web-scraped data and injects them into an Elasticsearch database. The embeddings are created using pre-trained machine learning models from TensorFlow Hub. The chatbot listens to users' questions and finds the most similar results by querying Elasticsearch.
Front-end Design and Implementation of a Windows Desktop Application
I was both a solver and a front-end developer.


How to Deploy Django on Heroku: A Pydantic Tutorial, Part 3

Optimize Your Environment for Development and Production: A Pydantic Tutorial, Part 2

Streamline Your Django Settings With Type Hints: A Pydantic Tutorial, Part 1
Education
Master's Degree in Aerospace Engineering (CFD)
Delft University of Technology - Delft, the Netherlands
Certifications
AWS Certified Cloud Practitioner
Amazon Web Services
Nanodegree, Cloud DevOps Engineer
Udacity
Google Kubernetes Engine
Google via Coursera
Deep Learning
Deeplearning.ai via Coursera
MongoDB for Developers
MongoDB University
Nanodegree, Full-stack Web Development
Udacity
Nanodegree, Self-driving Car Engineer
Udacity
Retrieving, Processing, and Visualizing Data with Python
Coursera
Skills
Libraries/APIs
NumPy, Pandas, llama.cpp, Microsoft Foundation Class (MFC) Library, Scikit-learn, TensorFlow, Matplotlib, Keras, Python Asyncio, Newman, Microsoft Foundation Classes (MFC), XGBoost, PyQt
Tools
Rasa.ai, GitHub, Docker Compose, Claude, ChatGPT, Terraform, Google Kubernetes Engine (GKE), Helm, GitLab, Amazon EKS, AWS CloudFormation, Amazon Virtual Private Cloud (VPC), Postman, Confluence, Jira, Jupyter, Bitbucket, Zoom, Slack, CircleCI, Ansible, PyPI, Pytest, Celery
Languages
C++, Python, SQL, Fortran, JavaScript, C++20, TypeScript
Frameworks
Django, Qt, Flask, AWS HA
Paradigms
Automation, DevOps, Agile, ETL, REST
Platforms
Docker, Amazon Web Services (AWS), Jupyter Notebook, Kubernetes, Ubuntu, Google Cloud Platform (GCP), Heroku, Windows, Linux, Amazon EC2, Zendesk, AWS Lambda
Storage
Elasticsearch, Amazon S3 (AWS S3), Google Cloud, Data Pipelines, MongoDB, PostgreSQL
Other
Chatbots, Natural Language Processing (NLP), Machine Learning, CI/CD Pipelines, Generative Pre-trained Transformers (GPT), Typer, Artificial Intelligence (AI), Open-source LLMs, Hugging Face, Large Language Models (LLMs), Crypto, Anthropic, APIs, Agentic AI, OpenAI, OpenAI GPT-4 API, Data Engineering, Full-stack, GitHub Actions, Graphical User Interface (GUI), FastAPI, Webhooks, WebAssembly (Wasm), Retrieval-augmented Generation (RAG), Motoko, Open Source, Data Science, Data Scraping, Gemini, caffeine.ai, Back-end, AWS ECS Fargate, Coderabbit, AWS Secrets Manager
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