Blas Grammar Checker
Irish, Welsh & English grammar
Only for Mac
Free
Mac
blas. Grammar Checker is a conservative writing assistant for Safari on Mac. It checks English and six Celtic languages: Irish, Welsh, Scottish Gaelic, Manx, Cornish and Breton.
LOCAL CHECKING
Choose your writing language, type in a supported web text field, and inspect underlined suggestions. Accept a suggested correction or dismiss it. Passive checks run on your device; typing alone does not upload your text. No account is required for local checking.
Coverage differs by language. Irish and Welsh have the deepest mutation coverage; the other Celtic languages have more limited spelling, mutation and agreement checks. The checker can miss errors and suggest changes you do not want. It does not replace proofreading or native-speaker judgement.
WHERE IT WORKS
Email compose boxes, comment fields, web forms and many rich-text editors. Custom editors may require checking pasted text in the extension popup. Not every website or editor is supported.
OPTIONAL ACCOUNT AND CLOUD FEATURES
A linked account can synchronise saved words and ignores. Optional English Deep Review requires a linked Premium account, the required consent and an explicit review request; selected text and context are sent to the service only for that request. Irish and Welsh dictation, where available, requires microphone permission and sends the recorded audio for transcription. These are separate from passive local checks. Celtic AI rewrites and translation are not provided.
SETUP
Open the containing app, enable Blas Grammar Checker in Safari Extensions, and grant access to the websites where you want checking. Choose the writing language in the extension popup.
See blasapp.com/support for help and blasapp.com/privacy for the privacy policy.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Accuracy update for all six Celtic languages: far fewer wrong suggestions on real-world text (names, abbreviations, web addresses, quoted English and dialect forms), new Welsh mutation checks, and quoted text in your chosen language is now checked.
The developer, threefold, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- User Content
- Browsing History
- Identifiers
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- THREEFOLD LTD
- Size
- 23.2 MB
- Category
- Productivity
- Compatibility
Requires macOS 10.14 or later.
- Mac
Requires macOS 10.14 or later.
- Mac
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Threefold Ltd