The Alpheios 3.0 Browser extensions can be installed in the latest desktop versions of the Chrome, Firefox and Safari browsers. You may experience problems with older versions and the Alpheios extensions cannot be installed on any mobile browser. To gain Alpheios functionality from a mobile device you must access a site where the Alpheios Embedded Library has been installed, such as Alpheios will not work with any version of Internet Explorer.

Details on minimum supported browser and operating system versions can be found in our System Requirements.

Alpheios can only be used reliably from mobile devices when accessing texts on sites that include the Alpheios Embedded Library, such as the Alpheios Mobile Reader portion of our own site. For instructions on how the Embedded Library can be added to any other site see

Mobile browsers do not provide adequate support for browser extensions like Alpheios.

Unfortunately, Alpheios no longer works in Google Docs with any browser and there are no immediate plans to restore that functionality. (Keeping up with Google's changes requires more resources than we currently possess)

If you have a long wordlist and are accessing Alpheios from a new browser over a slow connection, it may take a few minutes to fully download the wordlist into the browser's cache. Once downloaded to the cache, speed issues should be resolved.

The Alpheios wordlists use the "utf-8" character set encoding. You must be sure to specify utf-8 as the character set encoding in whatever program you import the downloaded file into (such as a spreadsheet program).

If you are using Alpheios in multiple browser tabs, the wordlist will be updated across all tabs with every lookup but you will need to refresh the page in order to see the updates immediately.

This could be caused by one of the following:

  • When we export a wordlist for use in a flashcard program, we exclude any words for which we were not able to retrieve short definitions.
  • The download for flashcards is also limited by default to 25 items. This is to guard against performance issues upon download. You can change this default in the Feature Options but we advise not more than 50.

No. Markup within a word will prevent Alpheios from recognizing it, unless the publisher of the web page being viewed has expressly added the attribute "data-alpheios-word-node" to the markup. Giving this attribute the value of "default" will allow Alpheios to ignore the internal markup, whether simply emphasis with bold or italics as in

<span data-alpheios-word-node="default"><b>f</b>ero</span>

or in accordance with scholarly markup such as the Leiden Conventions as in

<span data-alpheios-word-node="default">f[ero</span>

In both cases Alpheios will see "fero" without markup.

If the markup should not be ignored, the value should be set to "exact", as in

<span data-alpheios-word-node="exact">f[ero></span>

In which case Alpheios will see "f[ero".

Usually either double-clicking on a word or refreshing the browser page will make it reappear. If it still does not you can go to the Options tab and click Reset All. Note that you will have to reset any changes you have made from the defaults.

In order for the Alpheios extension to access language learning resources for words on any html page you choose to read on any website, it has to be able to function as an integral part of the browser. The messages from the browser requesting extra permissions during installation look alarming but are actually normal for browser extensions (and we actually request very limited permissions compared to what is possible). See the Alpheios Privacy Policy for more information.