A practical, web-friendly set of principles from Bruce Tognazzini — Apple's first Human Interface evangelist — covering anticipation, autonomy, efficiency, and the everyday mechanics of usable software.

WCAG 2.2 — POUR Principles

The 4 foundational principles of web accessibility — Perceivable, Operable, Understandable, Robust — and the 13 guidelines that make them actionable.

Laws of UX

A modern, psychology-based set of laws and effects that explain how people actually perceive, process, and decide — distilled from cognitive science into design-ready principles.

Side-by-side comparisons

Not sure which guideline to use?

Compare the most common heuristic guidelines principle by principle, with practical guidance on when each one wins.

Compare heuristic guidelines side-by-side

Side-by-side comparison

Dieter Rams' 10 vs Nielsen's 10

Dieter Rams' 10 principles vs Nielsen's 10 usability heuristics: where they overlap, where they don't, and which to use for a UX audit. With Heurio.

Side-by-side comparison

Nielsen's 10 vs Shneiderman's 8

Nielsen's 10 heuristics vs Shneiderman's 8 golden rules: where they overlap, where they diverge, and which to use for a UX heuristic evaluation. With Heurio.

Side-by-side comparison

Dieter Rams' 10 vs Norman's 6

Dieter Rams' 10 design principles ask whether an object is good; Don Norman's 6 principles diagnose whether users understand it. Side-by-side, with Heurio.

What is heuristic evaluation?

Heuristic evaluation is a usability-inspection method where a small group of reviewers checks an interface against a set of recognized usability principles — called heuristics. It surfaces the majority of UX problems quickly, without running a full user test, which makes it one of the cheapest and fastest ways to catch issues before a release.

In practice, reviewers walk through the product screen by screen, compare what they see to each rule in the chosen guideline, and log every violation with a severity rating. The output is a prioritized list of issues the team can act on.

When to use it

Before a release— catch obvious UX and copy issues while there’s still time to fix them.
Alongside usability testing— experts find what users miss; users find what experts miss.
On a competitor— benchmark their flows against the same rubric you hold yourself to.
During design review— turn subjective feedback into specific, rule-based observations.

How to pick a guideline

There isn’t one “correct” set of heuristics — each was written to answer a slightly different question. Nielsen’s 10 are the default for general product UX. Shneiderman’s 8 focus on interface consistency and predictability. Dieter Rams’ principles lean toward product design aesthetics. ISO 9241 is the formal, standards-body option when you need something auditable. Start with whichever fits the product you’re reviewing — you can always run a second pass with a different guideline later.

Running an evaluation in Heurio

Install the Chrome extension, open any live website, and switch to Comment View. Pick a guideline from the list below, then tag each comment you leave with the rule it violates and a severity. Share the result as a link, a Kanban board, or a PDF — no screenshots, no Loom, no “check page 3 of the doc.”

Six-step process

How to conduct a heuristic evaluation

Use this six-step process with any of the guidelines below. It works for the smallest landing page or the largest dashboard — and you can repeat it after every release.

Pick a heuristic guideline
Choose a recognized usability framework that fits your product — Nielsen's 10 for general product UX, Shneiderman's 8 for interface consistency, ISO 9241 for an auditable standard, or any of the other guidelines below.
Install the Heurio Chrome extension
Add Heurio to Chrome (or any Chromium-based browser like Edge, Brave, or Arc). It overlays comments on any live website without needing code changes.
Walk through the website screen by screen
Open the page you want to evaluate, switch the extension to Comment View, and review each flow against every rule in your chosen guideline.
Pin a comment for every issue you find
Click anywhere on the page to pin a heurio. Tag it with the violated rule (e.g. Nielsen #1 — Visibility of system status), set a severity (Neutral → Critical), and add a suggestion.
Prioritize and share the report
Sort the resulting list by severity to surface the most important issues first. Share the project as a link, a Kanban board, or export to PDF — no screenshots, no Loom, no separate doc.
Re-evaluate after fixes ship
Once the team resolves the highest-priority heurios, re-run the evaluation against the same guideline to confirm the fixes work and to surface any regressions.