Category Archives: Grammar Checking

Add Cysill Ar-lein to your website or code

Would you like to add Cysill Ar-lein to your web page, blog or app? You can now do this by using our widget and our new Cysill Ar-lein web service!


Cysill Ar-lein is an online Welsh language spelling and grammar checker and is the Language Technologies Unit’s most popular website. During 2014, there was a significant increase in its use, and in the number of texts corrected with it. In fact, there was an increase of 40%, with over a million pieces of Welsh language text checked by the website.

Cysill Ar-lein has a proven ability to give users who are not sure about their Welsh a strong confidence boost, and by allowing users to check their Welsh on many more websites and software packages, we hope that it will become possible to support and increase the confidence of even more users.

In accordance with the aims of the Language Technologies Unit, both the widget and the API service may be used free of charge.


Registering for a Cysill Ar-lein API key

By registering on our API service Centre you can get your own Cysill Ar-lein API key, to use in any way you’d like with the widget or the online API service. Go to Registering for an API key for further details.


Web Application widget

The Cysill Ar-lein web application widget is a feature that could be particularly useful for websites which allow users to compose text, such as comments.

The widget works via the web, so there’s no need to install any specialised software or even download files to any server or computer before getting started. All that’s required is to add the following few lines of HTML into your website:

        var CYSILL_API_KEY = "YOUR_API_KEY";
<script type="text/javascript" language="javascript" 

N.B. you will need to register for your API key and input it instead of ‘YOUR_API_KEY’

The widget can be placed anywhere within a web page by adding :

<div id='CysillArleinApp'></div>

The widget can be presented in a smaller embedded format next to some text, or on its own on a separate page. The system is flexible, and empowers you to use the spell-checker in the way which works best for you. Below is an example of the widget on Bangor University’s ‘Cymorth Cymraeg’ website.

Cysill Ar-lein o fewn dudalennau CymorthCymraeg Prifysgol Bangor

Here’s an another example of a simple Cysill Ar-lein website . Right-click on the page and choose: ‘View Page Source’ to see how simple the code really is.

The following page on GitHub explains in full how to use the widget.


Cysill Ar-lein API Service

Another offering from Cysill Ar-lein that we are excited to announce is the ability to embed Cysill Welsh language spelling and grammar checking functionality within your software using a new API service. This is the API service already used by the widget and the official Cysill Ar-lein website.

From today we are opening access to the Cysill Ar-lein API service to anyone for use with their coding projects and/or integrate with their software. This service is free.

N.B. you will need to register for your API key and input it instead of ‘YOUR_API_KEY’

We’ve loaded some examples onto GitHub showing how the API can be used with programming languages such as Python.

Go to:


The examples contain code that :