Denis Ostapenko
ENPT
Denis Ostapenko, portrait

Denis Ostapenko

Operations · Applied AI · UN Volunteer

I work on operations and AI workflows. Fifteen years in the field, then international logistics. These days I build tools and write about putting AI to work in real processes.

Selected work

Things I've built and opened up for others to use.

Language learning · Web app

English ↔ Português

The language app I wanted for myself. American English and Brazilian Portuguese, with audio, visual vocabulary, and practice in both directions.

2,774 learning items · Free to use

Open education · EN / PT-BR

AI Academy

A course on how language models and the systems around them work. From the basic mechanism to RAG, infrastructure, and implementation.

5 courses · 103 lessons · 172 primary sources

AI workflows · Open source

Agent Run Checkpoints

A public companion to my notes on bounded AI agents: task contracts and checkpoints for keeping agent work traceable.

Work in progress · Node.js

The book

The Word Machine

Understanding Language Models and Putting Them to Work

24 chapters and 30 diagrams. The complete English book is available as a free PDF and EPUB.

Download the book

From the notebook

All professional notes

Now

I'm working on bounded AI agents: how to give a system a clear job, check its work, and keep track of what changed. I'm also studying at the University of the People.

What I'm working through

Elsewhere

You can find my work and get in touch here.

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