Decoding AI Magazine | Paul Iusztin | Substack

LLM Engineer's Handbook is now thriving!

A framework for building LLM and RAG apps

Oct 22, 2024 • Paul Iusztin

Most Popular

Build your Second Brain AI assistant

Feb 6, 2025 • Paul Iusztin

Stop Building AI Agents

Jun 26, 2025 • Hugo Bowne-Anderson

Context Engineering: 2025’s #1 Skill in AI

Jul 22, 2025 • Paul Iusztin

From 0 to Pro AI Agents Roadmap

May 31, 2025 • Paul Iusztin

Decoding AI Magazine

Decoding AI Magazine

Join for content on designing, building, and shipping AI software that works. Learn AI engineering, end-to-end, from idea to production. Every Tuesday.

The latest from

Paul Iusztin

No Evals Dataset? Here's How to Build One from Scratch

Anca Ioana Muscalagiu

Your Agent's Reasoning Is Fine - Its Memory Isn't

Paolo Perrone

The Realistic Guide to Mastering AI Agents in 2026

Recent posts

No Evals Dataset? Here's How to Build One from Scratch

Build evaluators to signal problems that users actually care about. Step-by-step guide.

3 mins ago • Paul Iusztin

Stop Vibe Checking Your AI App

The holistic guide to integrating AI Evals: From optimization to production monitoring

Feb 10 • Paul Iusztin

Behind the Scenes of AI Observability in Production

What actually works after 6 months of trial and error

Feb 3 • Alejandro Aboy

Also on

Books

LLM Engineer's Handbook

Master the art of engineering Large Language Models from concept to production.

Courses

Agentic AI Engineering Guide

A 6-day email course to reveal the 6 critical mistakes that silently destroy agentic systems.

Agentic AI Engineering

Become an Agentic AI Engineer with a production-ready portfolio.

Explore Full Catalog

Write real code. Ship AI that actually works.

Perks

Exclusive Discounts

Books, self-paced courses, learning platforms, and live courses.

Access real-world guides. From the PoC purgatory to shipping AI products that work.

Foundations

No Evals Dataset? Here's How to Build One from Scratch

Build evaluators to signal problems that users actually care about. Step-by-step guide.

3 mins ago • Paul Iusztin

Stop Vibe Checking Your AI App

The holistic guide to integrating AI Evals: From optimization to production monitoring

Feb 10 • Paul Iusztin

How to Design Python AI Projects That Don't Fall Apart

A framework-agnostic approach to modular agents, workflows, and LLM apps using the pragmatic clean architecture design.

Jan 13 • Paul Iusztin

The AI Agents Roadmap Nobody Is Teaching You

9 lessons: from workflows to planning and multimodal AI agents. From scratch. Framework free.

Dec 16, 2025 • Paul Iusztin

Stop Converting Documents to Text. You're Doing It Wrong.

How to work with multimodal agents: images, PDFs, audio, and... text.

Dec 9, 2025 • Paul Iusztin

Case Studies

Behind the Scenes of AI Observability in Production

What actually works after 6 months of trial and error

Feb 3 • Alejandro Aboy

Your Agent's Reasoning Is Fine - Its Memory Isn't

Using GraphRAG to build a Production Engineer agent that knows dependencies, incidents, and ownership.

Jan 20 • Anca Ioana Muscalagiu

From 100+ AI Tools to 4: My Prod Stack

How simplicity beats complexity in real AI systems

Dec 30, 2025 • Paul Iusztin

We Killed RAG, MCP, and Agentic Loops. Here's What Happened.

A brutally honest case study of building our vertical AI agent and shipping it to production.

Dec 23, 2025 • Paul Iusztin

Stop Launching AI Apps Without This Framework

A practical guide to building an eval-driven loop for your LLM app using synthetic data, before you have users.

Oct 30, 2025 • Hugo Bowne-Anderson

Projects

Getting Agent Architecture Right

Designing real-world AI agents with MCP without burning your time, money, and SANITY.

Sep 6, 2025 • Anca Ioana Muscalagiu

Build with MCP Like a Real Engineer

Hands-on code for an enterprise AI PR Reviewer by unifying GitHub, Slack, and Asana through MCP.

Aug 30, 2025 • Anca Ioana Muscalagiu

Why MCP Breaks Old Enterprise AI Architectures

Build from scratch an AI PR reviewer integrated with GitHub, Slack and Asana that scales within your organization.

Aug 19, 2025 • Anca Ioana Muscalagiu

The King of Multi-Modal RAG: ColPali

Query your rich visual PDFs under a RAG web app

Jun 5, 2025 • Juan Ovalle

From 0 to Pro AI Agents Roadmap

Theory to API Deployments and LLMOps

May 31, 2025 • Paul Iusztin

Access real-world guides. From the PoC purgatory to shipping AI products that work.

Guests

Behind the Scenes of AI Observability in Production

What actually works after 6 months of trial and error

Feb 3 • Alejandro Aboy

The Realistic Guide to Mastering AI Agents in 2026

From zero to production in 6–9 months. What to learn, what to skip, and why most tutorials fail.

Jan 6 • Paolo Perrone

The Underrated Science of LLM Samplers

The secret sauce for balancing diversity, quality and precision

Nov 25, 2025 • Shmulik Cohen

Stop Launching AI Apps Without This Framework

A practical guide to building an eval-driven loop for your LLM app using synthetic data, before you have users.

Oct 30, 2025 • Hugo Bowne-Anderson

Building Reliable AI Agents with Durable Workflows

How to make agents resilient to any failure

Oct 23, 2025 • Peter Kraft and Paul Iusztin

Newsletter

The Realistic Guide to Mastering AI Agents in 2026

From zero to production in 6–9 months. What to learn, what to skip, and why most tutorials fail.

Jan 6 • Paolo Perrone

November Highlights: From Foundations To Production AI

AI Agents series finale. Controlling LLM output. Vertical AI agents & The Evals series.

Dec 18, 2025 • Paul Iusztin

Being too passive started to bother me

Finally, officializing the Decoding AI Magazine chat.

Nov 26, 2025 • Paul Iusztin

October Highlights: Your AI Engineering Roadmap.

AI Agents Foundations series. Evals series. NEXUS panel on AI Engineering.

Nov 6, 2025 • Paul Iusztin

My rough story of becoming an AI Engineer

Personal, raw, unfiltered story about my life

Nov 4, 2025 • Paul Iusztin

Access real-world guides. From the PoC purgatory to shipping AI products that work.

#nojs-banner { position: fixed; bottom: 0; left: 0; padding: 16px 16px 16px 32px; width: 100%; box-sizing: border-box; background: red; color: white; font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol"; font-size: 13px; line-height: 13px; } #nojs-banner a { color: inherit; text-decoration: underline; } This site requires JavaScript to run correctly. Please turn on JavaScript or unblock scripts