Home on The Essence of Software

Boston, April 27, 2026

Short videos about concept design

Object oriented modeling and its pitfalls.

Rethinking software structure to enable LLM coding

Learning about system design by writing concept specs and syncs

Learning about system design by reading concept specs and syncs

Learning about concept design by writing a concept spec

Criteria for reviewing concept definitions

Learning about concept design by reading a concept spec

Learning about concept design by comparing similar concepts

Oslo, August 25-26, 2025

Online, June 10, 12, 16, 24, 2025

Boston, March 2025

Workshop held in Woodinville, WA, in December 2024

A Proposal for a Concept-based App Architecture

Notes on the design of concept configurations

The first step to great software: scenarios of success

An idea you need to know One of the most important and useful ideas in software also happens to be one of the least well known.

Two sides of a coin The key to concept design is, perhaps not surprisingly, the idea of concepts.

The role of purposes From what to why.

Tactics for divergence Let’s consider some tactics that you might find useful as a software designer to make divergent design more effective.

Two modes of design thinking Design, whatever the domain, includes two different modes of thinking.

Why agile no longer makes sense in the LLM era.

Applying concept design to the camera rotation API

Notes on designing a GPT-powered tutor using concepts

Lessons learned from deploying concepts at scale.

Motivation: Defining Behavior The operational principle of a concept explains its archetypal behavior: how it’s typically used, and how it fulfills its purpose.

Notes on design of a GPT-powered tutor

Notes on design of a GPT-powered tutor

A Concept Exploration of Noosphere

A brief intro to concept design in three parts.

Integrity violations aren’t as common as I once expected.

The building blocks that social media apps use to control us.

Don Norman’s book helped improve interface design, but it also misled us.

Why a new discipline of software design is needed.

Why modularity matters To see why modularity is so critical in software design, consider what goes wrong when it’s missing.

In another tutorial, I showed a concept definition for Yellkey, a popular URL shortening service: concept Yellkey purpose shorten URLs to common words principle if you register a URL u for t seconds and obtaining a shortening s, looking up s will yi…

As I explained in another tutorial, the easiest and most effective way to define the behavior of an app precisely is to model it as a state machine.

Any software app, service or system can be viewed as a collection of interacting concepts.

When critical concepts are missing

If user experience runs deeper than the user interface, we need a way to talk about an app that isn’t just visual, and that captures behavior in a more fundamental way.

A compelling way to explain how something works is to tell a story.

In the 1980s, there was a revolution in software.

When you’re diagnosing a usability snag, or coming up with a new design idea, it’s helpful to know what level you’re working at.

Most of us* believe that simplicity is the key to design.

Seven criteria What makes a design fit for purpose depends—surprise!

What is a design problem?

Think about your favorite product, whether it’s a photo-editing app or a toaster, and ask yourself: how did it get to be so good?

What's the difference between design and engineering?

A How-To Guide for Removing Irregularities in Your App