Rated 3 out of 5 stars

It is that spell check going to the cloud, scanned and sent back or is it an offline tool like the old thunderbird spellchecker? It is a bit scary the "online" part.

This review is for a previous version of the add-on (4.4.0). 

This is documented in the description at https://addons.thunderbird.net/en-US/thunderbird/addon/grammar-and-spell-checker/: by default, the cloud is used and there's a privacy policy which describes the details. You can also run the server locally.

Rated 1 out of 5 stars

It requires "full, unrestricted access to Thunderbird, and your computer", which seems way too much.

This review is for a previous version of the add-on (4.4.0). 

There's no way we can check your text without that permission.

Rated 3 out of 5 stars

The LanguageTool plugin works well; however, I have noticed that this plugin is inferior to the LanguageTool editor. I can apply all corrections from the plugin, then paste the corrected text in the editor and find additional corrections. I would have expected the same performance for both the editor and the plugin.

Note: I found the same issue with the Firefox plugin and added the same comment there.

This review is for a previous version of the add-on (4.2.12). 

The editor and the add-on use the same backend (unless you use a local server), so the results are the same. You might have enabled picky mode in the editor, but not in the TB add-on. If you still see differences, please contact our support (see https://languagetool.org/legal for our email address).

Rated 5 out of 5 stars

Excellent!
I run a local server as explained on https://dev.languagetool.org/http-server. This way, Thunderbird, LibreOffice and Firefox use the same server, and LanguageTool works offline.
The proposed corrections in English and French always make sense and go far beyond native correction tools.

This review is for a previous version of the add-on (4.2.12). 

Rated 3 out of 5 stars

Thank you for bringing this add-on to TB - it helps greatly, especially if you need to constantly switch between multiple languages for multilingual communication. However, there seems to be an issue with this add-on - it does not allow to disable Thunderbird's spellchecker. Even though the Spelling options are switched off in Thunderbird, with this add-on ON Thunderbird underlines misspelled words in a composition window. If you uninstall this add-on all goes back to normal - no more underlines with TB's spelling OFF. Please fix this issue and I will be happy to give 5 stars :-). Otherwise this addon creates double marking for misspelled words which makes the text hard to work with.

UPDATE (29.11.2021) - Thank you for your quick reply. I've just sent all the requested details to your support email address. Looking forward to your feedback.

This review is for a previous version of the add-on (4.2.12). 

Sorry this doesn't work for you. Could you contact our support using the email you can find at https://languagetool.org/legal and send a screenshot, the TB version you use, and your operating system?

Rated 5 out of 5 stars

My favorite spell & grammar checker, finally on Thunderbird! I was waiting so long for this. If English is not the only language you use, there is no competitor.

The LT checking is not perfect, but from my perspective it's constantly being improved. I also like the open source approach (including adding grammar rules), and I'm recommending everyone supporting their development.

This review is for a previous version of the add-on (4.2.12). 

Rated 5 out of 5 stars

Impeccable fonctionne aussi bien que sous Firefox très pratique
merci aux développeurs

This review is for a previous version of the add-on (4.2.12). 

Rated 4 out of 5 stars

A great addition to Thunderbird and a worthwhile update with respect to the standard spell checker on my pc.
By default, your spelling is checked remotely, but a locally hosted version is available if you are worried about your privacy. If the setup process of the local host implementation were easier, it would get 5 stars from me.

This review is for a previous version of the add-on (4.2.12). 

Rated 5 out of 5 stars

The only grammar check addon for Thunderbird in Linux even when other popular grammar tools like Grammarly, ProWriting Aid etc show no interest in supporting Thunderbird.

This review is for a previous version of the add-on (4.2.12). 

Rated 5 out of 5 stars

Automatic Five Stars for being the only thunderbird add-on of its kind!

This review is for a previous version of the add-on (4.1.1). 

Rated 5 out of 5 stars

Simply GREAT! Wonderful to have this available for Thunderbird now! <3

This review is for a previous version of the add-on (4.1.1). 

Rated 5 out of 5 stars

LanguageTool is a mediocre grammar checker. I can't say I recommend the paid license, but the free plan is a welcome step up from vanilla spell checkers.

This add-on is excellent, however. Very responsive, and well designed. Only limited by the capabilities of LanguageTool itself.

Note, that you should be comfortable trusting a third-party with your privacy before using this tool. You can self-host the LanguageTool service, but by default it will send all of your composed email contents through the LanguageTool public API.

This review is for a previous version of the add-on (4.1.1). 

Rated 5 out of 5 stars

Works! This extension was really needed.

This review is for a previous version of the add-on (4.1.1). 

Rated 5 out of 5 stars

at long last this addon come true will full sync and now I can ditch Grammarly. Thanks Language tool

This review is for a previous version of the add-on (4.1.1).