Elijah Potter

Harper | Privacy-First Offline Grammar Checker Harper checks your writing instantly—fast, lightweight and utterly private—so you can polish every clause without surrendering a single keystroke.

For the orphans of Grammarly, I present Harper.

Harper is a free open-source English grammar checker.

It runs on-device, that means you have 100% certainty it doesn't violate your copyright by training large language models.

FUCK🖕AI

writewithharper.com

I find it very cool that harper (the grammar / prose) can correctly identify "a" vs "an" with initialisms

YouTube video by WordPress WordCamp US 2025: Elijah Potter "Your Words, Your Brain, Your Device"

I had the incredible opportunity to speak at WordCamp U.S. at Matt's suggestion. I met a number of wonderful, kind, and inviting people. It was my first WordCamp and first conference talk, so I was naturally nervous. The community made it feel easy.

www.youtube.com/watch?v=e-jY...

I've been working on making the UI for grammar checking better, for everyone.

elijahpotter.dev/articles/bet...

Lots of cloud providers like to brag about being able to scale with their users. I like to brag about not having to scale at all.

elijahpotter.dev/articles/loc...

I try to read at least two books a month. Whenever I have a chance, I then review the books to solidify the ideas in my mind.

elijahpotter.dev/articles/the...

Transformation Based Learning Harper is currently undergoing some pretty radical changes when it comes to its language analysis. These improvements will improve the output of our existing rule engine, in addition to making entirel...

I've been experimenting with Transformation-based Learning, which is an alternative to neural-network-based approaches for machine learning.

It's remarkably effective.

elijahpotter.dev/articles/tra...

I recently started testing Harper's Chrome extension with @microsoft.com's Playwright—it was easier than I thought:

elijahpotter.dev/articles/int...

#quality

Harper for Firefox Through Spellbolt SpellBolt is a Firefox extension that delivers Harper's fantastic grammar checking straight into your Firefox browser.

I love that Harper's core engine is so portable. It empowers devs to go out and build integrations on their own. For example, give SpellBolt a whirl!

elijahpotter.dev/articles/har...

Harper Is an Offline Alternative to Grammarly for Obsidian Obsidian is my favorite productivity tool. I use it for all of my writing, as a journaling app, and to replace multiple productivity tools. There's a big downside, though: no grammar checking tool.…

I found an offline alternative to Grammarly that you can run in Obsidian: https://lifehacker.com/tech/harper-offline-alternative-to-grammarly

Putting Harper in your Browser When our users install Harper, they should expect it to work anywhere they do.

We encountered a good many technical hurdles when building out support for the most visited sites on the internet.

elijahpotter.dev/articles/put...

Hey Justin! We're working on releasing our Chrome extension right now. I'd love to chat about how we can make it a better experience for everyone—wherever you write.