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Table of Contents

INNOQ supports this site.

INNOQ supports creation and maintenance of this site and the whole arc42 ecosystem. Thanx a lot, this support is highly appreciated.

About me (Gernot)

Gernot

My name is Gernot Starke. I’m:

  • happily married, we have two (grown-up) kids and live in Cologne, Germany.
  • Fellow at INNOQ,
  • Coaching and consulting medium and large-scale enterprises on topics around software architecture and methodical software engineering.
  • Co-founder and maintainer of arc42, the template for pragmatic and systematic software architecture documentation.
  • Founder of aim42, the open-source framework for systematic software architecture improvement.
  • Active member and working group lead within the International Software Architecture Qualification Board, iSAQB.
  • Trainer for the iSAQB curriculum (modules FOUNDATION, IMPROVE, REQ4ARC and ADOC).
  • Regular speaker at IT-conferences.
  • Author and co-author of more than a dozen books on software architecture, patterns, arc, and the like. Most of these books are written in German. Take a look at Leanpub for some of my English books.
  • Author of quite a few articles

Acknowledgements

Find the complete list of contributors here

Color Scheme

Each content type carries an identity colour. Cards use a paper background with a coloured rail on the left — the same pattern used across detail pages and section headers, so the colour acts as a wayfinding cue rather than decoration.

Dimensions
Rail / accent: #1A3A5C
Text on dark fill: #C8E6F5 · 8.5:1 (AAA)
Characteristics
Rail / fill: #00B8F5
Text on fill: #003366
Requirements
Rail / fill: #FFB3B3
Text on fill: #8B0000
Standards
Rail / fill: #FFC95C
Text on fill: #2C3E50
Approaches
Rail / fill: #92EF80
Text on fill: #1B5E20
Trade-offs (approach relation)
Rail / accent: #A04323
Soft fill: #FBE9E3 · Muted: #6B6B6B
Articles & Background Reading
The longform / meta register: articles, background reading, and the how-to guide. Anchored to the site identity rather than to any one content type, so they share the brand violet rail.
Rail / accent: #682D63 · Soft fill: #E6DAF2

Accessibility note: identity colours are validated for WCAG contrast on the surfaces they appear on; see WCAG Accessibility Report and Lighthouse Quality Report.

Tooling and Build

  • This page is based upon Jekyll, a static website generator.
  • It’s maintained on Github and published via github-pages.
  • A custom Docker Compose environment handles dependency installation, graph data generation, JavaScript bundling (esbuild), and Jekyll serving — no manual toolchain wiring needed.
  • In case you want to run the site locally, use docker compose up after cloning the repo locally.

  • The site’s UI is a bespoke design, crafted to reflect the arc42 brand: a violet/teal palette, accessibility-first typography, and an interactive D3.js force graph as the visual centrepiece.

  • build_revision: 6fa4c9da44f93c099a0c5905e2b9bc8c9f47cb28,
  • last built and published on Sat Sep 5 15:31:06 2026

Lighthouse Quality Report

We continuously monitor the site’s quality using Google Lighthouse. It audits performance, accessibility, SEO, and best practices.

View the latest Lighthouse Report

Content Analytics

Here we analyze our content, especially the links between content elements. In the long run we aim at having everything well-connected:

Qualities without Tag (aka property)

Tags assign a quality to one or more high-level properties, like secure or usable. A quality without a tag shows up in no property overview and is hard to find.

All qualities in this site have at least one tag defined (excluding synonyms, which inherit tags from their canonical entry).

Orphan Qualities

The related: field of a quality names the other qualities it is connected to. A quality that names none is a dead end: the graph shows it isolated, and readers have nowhere to go from it.

All qualities in this site have at least one directly related quality defined (excluding synonyms, which inherit relations from their canonical entry).

Synonyms

Different terms often mean the same quality. We keep one canonical page per concept and redirect the alternative terms to it, instead of maintaining near-duplicate content.

See our complete Quality Aliases and Synonyms mapping for details.

Total synonym pairs: 28

The synonym system ensures:

  • Canonical terms have comprehensive content and definitions
  • Graph visualization shows single nodes with multiple labels

Qualities without Requirements

Requirements make a quality concrete and testable. They point at qualities via their related: field — a quality nobody points at stays an abstract term.

The following 36 qualities currently have no requirements directly related to them (excluding synonyms):

Co-existence, Communicability, Conciseness, Consent Management, Controllability, Credibility, Data Minimization, Data Residency, Devops-Metrics, Distributability, Durability, Effectiveness, Energy Proportionality, Expected physical environment, Features, Functional Adaptability, Functional suitability, Immunity, Injection Resistance, Intervenability, Legal Requirements, Longevity, Model Transparency, Operational constraint, Operational and Environment Requirements, Personalization, Safe integration, Securability, Self-containedness, Self-descriptiveness, Simplicity, Suitability, Themability, Upgradeability, User engagement, Versatility,

Orphan Relations

Every quality has a related: field in its header, listing the names of related qualities. Here we check for entries in that field that name a quality which does not exist.

All quality relations reference existing qualities - no orphan relations found.

Standards without Qualities

Every quality standard (like ISO-5055) should have at least one quality related to it. Standards are linked from the standards: field of the qualities, not from the standard page itself.

All standards have at least one quality related to them.

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