What does WCAG 3.1.4 (Abbreviations) require?

It requires a mechanism to find the expanded form or meaning of abbreviations. The simplest way to satisfy it in body text is to spell out the full term on first use with the acronym in parentheses, for example 'Application Programming Interface (API)'.

How does the tool detect an acronym?

It finds tokens of two or more capital letters (optionally with digits, like H2O or PDF417) and checks whether an expansion appears in parentheses nearby on first use. If none is found, the acronym is flagged.

Why are common acronyms still flagged?

Even widely known acronyms can be unfamiliar to some readers or assistive tech, so WCAG asks for a definition mechanism. The tool suggests a known expansion where it has one, but you decide which acronyms your audience truly needs defined.

Does it count an acronym as defined if I expand it later?

No. WCAG 3.1.4 is about the first occurrence, so the expansion must accompany or precede the first use. An acronym expanded only halfway through the document is still flagged on its first appearance.

Is my text sent to a server?

No. The acronym dictionary is bundled into the page and all scanning runs in your browser. Your text never leaves your device, so internal documentation is safe to check.

Abbreviation & Acronym Expander

The Abbreviation & Acronym Expander scans your copy for capitalised acronyms that are never defined on first use and flags each one as a potential WCAG 2.1 3.1.4 (Abbreviations) issue. The criterion asks for a mechanism to find the expanded form of an abbreviation; in plain body text the standard approach is to spell out the full term the first time it appears, with the acronym in parentheses. This tool finds the acronyms you forgot to define.

How it works

Detection. The tool tokenises your text and identifies acronyms — runs of two or more capital letters, optionally mixed with digits, such as API, GDPR, H2O, or PDF417.
First-use check. For each distinct acronym it looks at the first occurrence and checks whether an expansion appears alongside it. Two patterns satisfy the rule: the acronym followed by its expansion in parentheses — API (Application Programming Interface) — or the expansion followed by the acronym in parentheses — Application Programming Interface (API).
Suggestion. If no expansion is present, the acronym is flagged. Where the term is in the bundled dictionary (NHS, GDPR, URL, API, HTML, and dozens more), a suggested expansion is shown so you can paste it straight in.

Tips and notes

Define each acronym once, on its first appearance, then use the short form freely afterwards.
Very common items like UK, US, OK, and AM/PM are excluded from flagging because spelling them out hurts more than it helps; adjust your copy to your audience.
For acronyms that recur across a long page, also consider an HTML <abbr title="…"> element so assistive technology can surface the expansion on demand — that satisfies the same criterion programmatically.