I would much rather check my writing against grammatical rules that are hard coded in an open source program—meaning that I can change them—than ones that I imagine would be subject to prompt fiddling or worse; implicitly hard coded in a tangle of training data that the LLM would draw from.
IMO not using LLMs is a big plus in my book. Grammarly has been going downhill since they've been larding it with "AI features," it has become remarkably inconsistent. It will tell me to remove a comma one hour, and then tell me to add it back the next.
Grammarly sometimes gets stuck in a loop, where it suggests changing from A to B. It then immediately suggests changing from B to A again, continuing to suggest the opposite change every time I accept the suggestion.
It's not a problem; I make the determination which option I like better, but it is funny.
General purpose LLMs seem to get very confused about punctuation, in my experience. It's one of their big areas of obvious failing. I'm surprised Grammarly would allow this to happen.
Grammarly came out before the LLMs. I'm not sure what approach it took, but they're likely feeling a squeeze as LLMs can tell you how to rewrite a sentence to remove passive voice and all that. I doubt the LLMs are as consistent (some comments below show some big issues), but they're free (for now).
There are two versions of the LanguageTool: open source and cloud-based. Open source checks the individual words in the dictionary just like the system's spell checker. Maybe there is something more to it, but in my tests, it did not fix even obvious errors. It's not an alternative to Grammarly or this tool.
I'm a long-time Grammarly user. I just tried Harper, and it simply performs very poorly. It is a good initiative, but I don't feel the current state of this software to be worthwhile.
Why wouldn't you want an LLM for a language learning tool? Language is one of things I would trust an LLM completely on. Have you ever seen ChatGPT make an English mistake?
Yeah, I agree. An open-source LLM-based grammar checker with a user interface similar to Grammarly is probably what I'm looking for. It doesn't need to be perfect (none of the options are); it just needs to help me become a better writer by pointing out issues in my text. I can ignore the false positives, and as long as it helps improve my text, I don't mind if it doesn't catch every single issue.
Using an LLM would also help make it multilingual. Both Grammarly and Harper only support English and will likely never support more than a few dozen very popular languages. LLMs could help cover a much wider range of languages.
Grammarly is all in on AI and recently started recommended splitting "wasn't" and added the contraction to the word it modified. Example: "truly wasn't" becomes "was trulyn't"
Hm ... I wonder, is Grammarly also responsible for the flood of contraction of lexical "have" the last few years? It's standard in British English, but outside of poetry it is proscribed in almost all other dialects (which only permit contraction of auxiliary "have").
Even in British I'm not sure how widely they actually use it - do they say "I've a car" and "I haven't a car"?
In my experience "I've a car" is much more common than "I haven't a car" (I've never heard the latter construct used, but regularly hear the former in casual speech). "I haven't got a car" or "I've no car" would be relatively common though.
uh. yes? it's far from uncommon, and sometimes it's ludicrously wrong. Grammarly has been getting quite a lot of meme-content lately showing stuff like that.
it is of course mostly very good at it, but it's very far from "trustworthy", and it tends to mirror mistakes you make.
Do you have any examples? The only time I noticed an LLM make a language mistake was when using a quantized model (gemma) with my native language (so much smaller training data pool).
Would be nice if they had a website where you could demo/test it before downloading extensions and stuff. Their firefox extension opens to this page https://writewithharper.com/install-browser-extension but when you paste in anything more than a few paragraphs the highlighting is all messed up.
I used to see ads for Grammarly and wondered if anyone was using it.
Then post COVID with the increase in screen sharing video calls, I soon realised nearly every non-native English speaker from countries around the world heavily relied on it in their jobs. As I could see it installed when people share screens.
Slightly controversial compared to other comments here but I haven't used Grammerly at all since LLMs came out. Even a 4B local LLM is good enough to rephrase all forms of text and fix most grammer mistakes.
I think a lot of value comes by integrating with a language server and/or browser extensions.
Do you have a setup where this is possible or do you copy paste between text fields? (Genuine question. I’d love to use a local LLM integrating with an LSP).
I wish it had keyboard shortcuts. As a Vim user, in Chrome it's tedious to click on every suggestion given by the app. Also, maybe add a "delay" so it doesn't think the currently-being-typed word is a mistake (let me finish typing first!).
Otherwise, it's great work. There should be an option to import/export the correction rules though.
“Think of how poorly the average person writes, and realize half of them write worse than that.”
(George Carlin or something, quote's veracity depends on what you mean by “average.”)
I think everybody could benefit from having something like Grammarly on their computer. None of us writes perfectly, and it's always beneficial to strive for improvement.
I think it is anyone who wanna make sure they write correctly. I know for example David Sparks (MacSparky https://www.macsparky.com ) uses it (or at leased used it). And he was an American lawyer and he says writing has been his passion his whole life so I assume his English is better than the average person.
LLMs are not nice to use for spell checking. I do not want to read a wall of text from LLM just to find a missed article somewhere and I want to receive feedback as I type.
Also, once I asked LLM to check the message. It said everything looked fine and made a copy of the message in its response with one sentence in the middle removed.
Looks cool, but it's weird to constantly make comparisons to Grammarly (in the post title, description section of the site, benchmarks) when this is clearly a rule-based spellcheck and very different from what Grammarly offers.
Instead tell me how it compares to the built-in spellcheck in my browser/IDE/word processor/OS.
this is the right direction. rulebased, local, transparent. not perfect yet, but that's not the point. getting something lightweight and tweakable matters more than catching every edge case out of the box. if it misses, you add rules. simple as that. if you expect it to match grammarly day one then might be we are missing the tradeoff
this solution is just fundamentally insufficient. in the age of LLMs it's pretty insane to imagine programmers manually hard-coding an arbitrary subset of grammatical corrections (sure: it's faster, it's local first, but it's not enough). on top of that, English (like any other natural language) is such a complicated beast that you will never write a classic deterministic parser that's sophisticated enough to allow you to reliably implement even the most basic of grammatical corrections (check the other comments for examples). it's just not gonna happen.
i guess it's a nice and lightweight enhancement on top of the good old spellchecker, though
"PointIsMoot" => (
["your point is mute"],
["your point is moot"],
"Did you mean `your point is moot`?",
"Typo: `moot` (meaning debatable) is correct rather than `mute`."
),
From a quick look phrase corrections is just one type of rule. There are many other rules, some are dynamic like when to use "your" vs "you're", oxford commas, etc.
That it doesn't use LLMs is its advantage, it runs in under 10ms and can be easily embedded in software and still provide useful grammar checking even if it's not exhaustive
I never understood the appeal of grammar tools. If you have reached the minimum professional/academic level needed to be designated to write something, shouldn't you at least be capable of verifying its semantic "correctness" just by reading through it once yourself?
Why would you pass a writing job to someone who isn't 100% fluent in the language and then make up for it by buying complex tools?
As a non native English speaker/writer there are a bunch of errors I miss, no matter how much attention I pay and how much I proofread, and these tools are useful to catch those.
I know for example David Sparks (MacSparky https://www.macsparky.com ) uses it (or at leased used it). And he was an American lawyer and he says writing has been his passion his whole life so I assume his English is better than the average person.
I use it (well, languagetool) in the free version for comments on sites like this. It directly catches mistakes I make, that I'd normally only catch on re-reads. From typos, over my brain doing weird stuff, to sometimes things I simply didn't (actively) know.
Odd choice that the example text on the homepage is almost all obvious typos that a standard spell check would pick up.
I would much rather check my writing against grammatical rules that are hard coded in an open source program—meaning that I can change them—than ones that I imagine would be subject to prompt fiddling or worse; implicitly hard coded in a tangle of training data that the LLM would draw from.
The Neovim configuration for the LSP looks neat: https://writewithharper.com/docs/integrations/neovim
The whole thing seems cool. Automattic should mention this on their homepage. Tools like this are the future of something.
You would lose out on evolution of language.
Natural languages evolve so slowly that writing and editing rules for them is easily achievable even this way. Think years versus minutes.
IMO not using LLMs is a big plus in my book. Grammarly has been going downhill since they've been larding it with "AI features," it has become remarkably inconsistent. It will tell me to remove a comma one hour, and then tell me to add it back the next.
Grammarly sometimes gets stuck in a loop, where it suggests changing from A to B. It then immediately suggests changing from B to A again, continuing to suggest the opposite change every time I accept the suggestion.
It's not a problem; I make the determination which option I like better, but it is funny.
General purpose LLMs seem to get very confused about punctuation, in my experience. It's one of their big areas of obvious failing. I'm surprised Grammarly would allow this to happen.
The internet, especially post phone keyboards, is extremely inconsistent about punctuation. I’m not sure how anyone could think an llm wouldn’t be.
Thank you. In general my grammarly and gboard predictions have become so, so bad over the last year.
So is there a similar tool but based on an LLM?
Not that I think LLM is always better, but it would be interesting to compare these two approaches.
Grammarly is (was) written in Common LISP https://www.grammarly.com/blog/engineering/running-lisp-in-p...
Given LISP was supposed to build "The AI" ... pretty sad than a dumb LLM is taking its place now
Grammarly came out before the LLMs. I'm not sure what approach it took, but they're likely feeling a squeeze as LLMs can tell you how to rewrite a sentence to remove passive voice and all that. I doubt the LLMs are as consistent (some comments below show some big issues), but they're free (for now).
> It will tell me to remove a comma one hour, and then tell me to add it back the next.
So just like English teachers I see
LanguageTool (a Grammarly competitor) is also open source and can be managed locally:
https://github.com/languagetool-org/languagetool
I generally run it in a Docker container on my local machine:
https://hub.docker.com/r/erikvl87/languagetool
I haven't messed with Harper closely but I am aware of its existence. It's nice to have options, though.
It would sure be nice if the Harper website made clear that one of the two competitors it compares itself to can also be run locally.
There are two versions of the LanguageTool: open source and cloud-based. Open source checks the individual words in the dictionary just like the system's spell checker. Maybe there is something more to it, but in my tests, it did not fix even obvious errors. It's not an alternative to Grammarly or this tool.
"Me and Jennifer went to have seen the ducks cousin."
No errors detected. So this needs a lot of rule contributions to get to Grammarly level.
I was initially impressed. But then I tested a bunch, it wasn't catching some really basic things. Mostly hit or miss.
Similarly 0 grammatical errors flagged: "My name John. What your name? What day today?"
What the duck is that test
Nominative vs objective
There's a little more going on than that.
I'm a long-time Grammarly user. I just tried Harper, and it simply performs very poorly. It is a good initiative, but I don't feel the current state of this software to be worthwhile.
Why wouldn't you want an LLM for a language learning tool? Language is one of things I would trust an LLM completely on. Have you ever seen ChatGPT make an English mistake?
Yeah, I agree. An open-source LLM-based grammar checker with a user interface similar to Grammarly is probably what I'm looking for. It doesn't need to be perfect (none of the options are); it just needs to help me become a better writer by pointing out issues in my text. I can ignore the false positives, and as long as it helps improve my text, I don't mind if it doesn't catch every single issue.
Using an LLM would also help make it multilingual. Both Grammarly and Harper only support English and will likely never support more than a few dozen very popular languages. LLMs could help cover a much wider range of languages.
Grammarly is all in on AI and recently started recommended splitting "wasn't" and added the contraction to the word it modified. Example: "truly wasn't" becomes "was trulyn't"
https://imgur.com/a/RQZ2wXA
I don't think an LLM would recommend an edit like that.
Has to be a bug in their rule-based system?
Hm ... I wonder, is Grammarly also responsible for the flood of contraction of lexical "have" the last few years? It's standard in British English, but outside of poetry it is proscribed in almost all other dialects (which only permit contraction of auxiliary "have").
Even in British I'm not sure how widely they actually use it - do they say "I've a car" and "I haven't a car"?
In my experience "I've a car" is much more common than "I haven't a car" (I've never heard the latter construct used, but regularly hear the former in casual speech). "I haven't got a car" or "I've no car" would be relatively common though.
"they" say "I haven't got a car".
Contractions are common in Australian English to, though becoming less so due to the influence of US English.
This is what peak innovation looks like
uh. yes? it's far from uncommon, and sometimes it's ludicrously wrong. Grammarly has been getting quite a lot of meme-content lately showing stuff like that.
it is of course mostly very good at it, but it's very far from "trustworthy", and it tends to mirror mistakes you make.
Do you have any examples? The only time I noticed an LLM make a language mistake was when using a quantized model (gemma) with my native language (so much smaller training data pool).
Because this "language learning tool" will be dominantly used to avoid actually learning the language.
Given this is an Automattic product, I'm hesitant to use it. If it gets remotely successful, Matt will ruin it in the name of profit.
It's FOSS, so even if the worst happens, anyone could just fork the last good version and continue development there.
Oh, that’s a big no from me then.
Would be nice if they had a website where you could demo/test it before downloading extensions and stuff. Their firefox extension opens to this page https://writewithharper.com/install-browser-extension but when you paste in anything more than a few paragraphs the highlighting is all messed up.
Comes with a great LSP server capable of checking grammar in code comments:
https://writewithharper.com/docs/integrations/language-serve...
I used to see ads for Grammarly and wondered if anyone was using it.
Then post COVID with the increase in screen sharing video calls, I soon realised nearly every non-native English speaker from countries around the world heavily relied on it in their jobs. As I could see it installed when people share screens.
Huge market, good luck.
Very cool. Has anyone integrated this into their own app? How was your experience?
Slightly controversial compared to other comments here but I haven't used Grammerly at all since LLMs came out. Even a 4B local LLM is good enough to rephrase all forms of text and fix most grammer mistakes.
I think a lot of value comes by integrating with a language server and/or browser extensions.
Do you have a setup where this is possible or do you copy paste between text fields? (Genuine question. I’d love to use a local LLM integrating with an LSP).
"For most documents, Harper can serve up suggestions in under 10ms." 10l is OK. 10kg as well. Why is 10ms wrong?
“Yo who dis?”
Passes.
For reference: https://youtu.be/w-R_Rak8Tys?si=h3zFCq2kyzYNRXBI
I wish it had keyboard shortcuts. As a Vim user, in Chrome it's tedious to click on every suggestion given by the app. Also, maybe add a "delay" so it doesn't think the currently-being-typed word is a mistake (let me finish typing first!).
Otherwise, it's great work. There should be an option to import/export the correction rules though.
Who is the target market is for Grammarly? Working professionals who speak English as a second language?
“Think of how poorly the average person writes, and realize half of them write worse than that.”
(George Carlin or something, quote's veracity depends on what you mean by “average.”)
I think everybody could benefit from having something like Grammarly on their computer. None of us writes perfectly, and it's always beneficial to strive for improvement.
I think it is anyone who wanna make sure they write correctly. I know for example David Sparks (MacSparky https://www.macsparky.com ) uses it (or at leased used it). And he was an American lawyer and he says writing has been his passion his whole life so I assume his English is better than the average person.
Adam Engst from TidBITs, a person whose job has been writing things for all his life, also uses Grammarly:
https://tidbits.com/2025/01/30/why-grammarly-beats-apples-wr...
People who haven't heard of LLMs
LLMs are not nice to use for spell checking. I do not want to read a wall of text from LLM just to find a missed article somewhere and I want to receive feedback as I type.
Also, once I asked LLM to check the message. It said everything looked fine and made a copy of the message in its response with one sentence in the middle removed.
Looks cool, but it's weird to constantly make comparisons to Grammarly (in the post title, description section of the site, benchmarks) when this is clearly a rule-based spellcheck and very different from what Grammarly offers.
Instead tell me how it compares to the built-in spellcheck in my browser/IDE/word processor/OS.
this is the right direction. rulebased, local, transparent. not perfect yet, but that's not the point. getting something lightweight and tweakable matters more than catching every edge case out of the box. if it misses, you add rules. simple as that. if you expect it to match grammarly day one then might be we are missing the tradeoff
this solution is just fundamentally insufficient. in the age of LLMs it's pretty insane to imagine programmers manually hard-coding an arbitrary subset of grammatical corrections (sure: it's faster, it's local first, but it's not enough). on top of that, English (like any other natural language) is such a complicated beast that you will never write a classic deterministic parser that's sophisticated enough to allow you to reliably implement even the most basic of grammatical corrections (check the other comments for examples). it's just not gonna happen.
i guess it's a nice and lightweight enhancement on top of the good old spellchecker, though
It is available in Autommatic's Github repository:
https://github.com/Automattic/harper
Automattic*
Great! Please create an iOS keyboard with Harper
This seems to use a hard coded list of explicit rules, not an LLM
https://writewithharper.com/docs/rules
https://github.com/Automattic/harper/blob/0c04291bfec25d0e93...
From a quick look phrase corrections is just one type of rule. There are many other rules, some are dynamic like when to use "your" vs "you're", oxford commas, etc.
That it doesn't use LLMs is its advantage, it runs in under 10ms and can be easily embedded in software and still provide useful grammar checking even if it's not exhaustive
Looks awesome! I’ll give it a try over language tool.
Is there any reason why there is no firefox extension?
Very buggy, but great start!!
I.e. if you write an "MISTAEK" and then you scroll the highlight follows me around the page
I think if you can self host language tool, it would still be the better option.
nice name!
Good start. But still has bugs i guess.
I tried with the following phrase -- "This should can't logic be done me." --
No errors.
Is this using local LLMs or some other engine?
I don't think it uses an LLM.
https://github.com/Automattic/harper
I never understood the appeal of grammar tools. If you have reached the minimum professional/academic level needed to be designated to write something, shouldn't you at least be capable of verifying its semantic "correctness" just by reading through it once yourself?
Why would you pass a writing job to someone who isn't 100% fluent in the language and then make up for it by buying complex tools?
As a non native English speaker/writer there are a bunch of errors I miss, no matter how much attention I pay and how much I proofread, and these tools are useful to catch those.
I know for example David Sparks (MacSparky https://www.macsparky.com ) uses it (or at leased used it). And he was an American lawyer and he says writing has been his passion his whole life so I assume his English is better than the average person.
I use it (well, languagetool) in the free version for comments on sites like this. It directly catches mistakes I make, that I'd normally only catch on re-reads. From typos, over my brain doing weird stuff, to sometimes things I simply didn't (actively) know.
Have you considered that some people aren’t 100% fluent in English but still competent?
Which LLM is running with Harper?
None