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- "Sinceerly" is a Chrome plugin that rewrites your perfectly worded emails to add typos.
- You can select "Subtle," "Human," or "CEO" modes for maximum brevity and typos.
- In a time when AI writing is common, typos are a status symbol showing you hand-wrote an email (or not).
Not so long ago, writing an email with perfect grammar and spelling was a sign of professionalism, thoughtfulness and care, of education and intelligence, of a sharp and agile mind.
Now, it just means we assume you're a lazy jerk who used ChatGPT or some other AI tool.
The pendulum has finally swung, and after several centuries of the English language, good writing in private communication is no longer a prized thing. Now we are entering a terrifying and chaotic period in which typos are good, and all-lower-case missives connote power.
The era of keyboard chaos is upon us.
Typos are increasingly a status symbol showing you hand-crafted an email instead of using AI. If your email is too perfect, it might scream "AI!" So, of course, there's an AI tool that adds typos back into your AI-written emails.
I made the anti-Grammarly. Mess up your emails with AI. https://t.co/R6kdTpoc0W pic.twitter.com/1AF5qrCFwT
— Ben Horwitz (@horwitzben) April 23, 2026
Sinceerly is a Chrome plugin created by Ben Horwitz that will rewrite your emails to add back mistakes, making them look more human.
There are three modes:
"Subtle," which will streamline the text by knocking out filler words and turning things into contractions when it can. Then there's "Human," which adds an even more conversational tone — both Subtle and Human typically add a typo in the first sentence.
Here is a sample email I wrote to my boss to tell him about my lunch plan:
Business Insider
Here's that same email, turned into "CEO" mode:
Business Insider
And finally, there's "CEO," which goes all lowercase and injects intense brevity. If there's no signature in your email, sometimes it adds a "sent from my iPhone" (lol).
CEOs indeed do have a really specific email style that is often very fast in response time and short, which can reflect the power differential between the boss and the person they're corresponding with.
Horwitz, who is about to graduate from Harvard Business School in May, told me he made Sinceerly using Claude and was inspired by his own experience.
"I am a terrible typist, naturally, and lightly dyslexic," he said. "It would take me so long in my first job straight out of college to write emails and make sure there were no typos and everything. When Grammarly came around, it was like, 'Oh, OK, this is pretty good for me.' But now my email inbox is filled with AI slop."
Horwitz told me he made the plugin just for fun, as a goof, and doesn't necessarily expect a lot of people to pay for it (after a few free test runs, it asks you to pay $4.99 to keep using it). Horwitz isn't really in it for the money; he likes making playful pranks about business life (he previously made a collection of stitched baseball hats you could buy with titles like "product," "engineering," and "gtm" for founders who, uh, wear a lot of hats).
I don't think the ink is yet dry on the status of typos in emails; AI in digital communication is still so new, and the norms around it are still evolving.
As a terrible typist myself, I am pro-typo and believe that we should let our messy human fingers speak for us. If we're asking someone to take the time to read our emails, we should take the time to write them — even if that includes a few mistakes.