Sinceerly: The AI Tool That Adds Controlled Typos to Counter AI-Generated Emails

For someone with dyslexia who writes professionally, typos are more than just errors—they’re a persistent source of anxiety. Signing an email with “bet” instead of “best” or mistyping “felt” as “left” can feel like a professional misstep. Society often equates typos with carelessness or incompetence, yet in an era dominated by AI-generated perfection, those very mistakes might be the last remnants of human authenticity.

Enter Sinceerly, an AI-powered browser extension designed to do the opposite of Grammarly. Instead of correcting errors, it introduces controlled typos to make emails sound more human. The tool, created by Ben Horwitz—a student at Harvard Business School and investment partner at Dorm Room Fund—aims to challenge our reliance on flawless, AI-crafted prose.

Why Sinceerly Was Created

Horwitz launched Sinceerly after noticing a growing trend: emails that clearly read like AI-generated content. Frustrated by the lack of authenticity in digital communication, he sought to “hold up a mirror” to our complicated relationship with technology. His question: If we use AI to write, can we also use AI to un-AI our writing?

“If we are using AI to write, then in this moment, can we use AI to un-AI our own writing? That’d be funny.”

The name “Sinceerly” is a playful misspelling, both on-brand and a cost-saving move for Horwitz, who purchased the domain affordably as a student. The tool, which he shared on X this week, mimics Grammarly’s interface while offering three distinct editing levels: subtle, human, and CEO.

How Sinceerly Works

Sinceerly rewrites long, jargon-heavy AI-generated paragraphs into more concise, conversational versions. Each level adjusts the tone and structure differently:

• Subtle: Condenses a five-line paragraph into three lines, removing unnecessary jargon.
• Human: Adds slang, abbreviations, and further trims the text for a casual tone.
• CEO: Takes authenticity to the extreme, producing emails like: “think we should connect. potential here. quick call this week? lmk Sent from my iPhone”

The tool’s “CEO” mode reflects a growing trend where brevity and typos are seen as status symbols in business. The idea? Executives are too busy to worry about punctuation.

Testing Sinceerly: Did It Work?

Horwitz put Sinceerly to the test by sending edited emails to five Fortune 500 CEOs. Four responded—proof, he says, that the tool could transform AI slop into something more relatable. The replies were revealing:

• Each email was under ten words.
• Two of the responses contained typos.
• One CEO even addressed Horwitz as “Larry.”

While Horwitz’s experiment wasn’t rigorously scientific, it highlighted a key insight: CEOs write like humans, typos and all.

Could Imperfection Be the Future of Business Communication?

Sinceerly started as a joke, but its concept taps into a real frustration. As AI-generated content floods inboxes, authenticity becomes a rare commodity. Some email marketers have already experimented with typos in subject lines, reporting a 40% increase in open rates—because recipients assumed the emails were sent by real people, not bots.

For professionals who struggle with perfectionism or those who simply want to stand out in a sea of polished AI prose, tools like Sinceerly offer a refreshing alternative. Whether it’s satire or a glimpse into the future of communication, one thing is clear: the demand for human touch in digital interactions isn’t going away.