Sinceerly — Be sinceerly human
We believe that this document is fully human-written.
Hacker News Article AI Analysis
Content Label
Human
AI Generated
0%
Human
100%
Window 1 - Human
AI to undo your AI writing.3 free emails. No credit card.
Subtle
Human
CEOSent from my iPhone
Kill the emdashEmdashes scream AI. Sinceerly kills them.No more "not just…"Undo the annoying phrases that AI uses over and over.Add some typosHumans make mistkaes.
Product
Three levels.One slider.
Original email
AI slop
I wanted to reach out to express my interest in connecting regarding potential synergies between our organizations. I believe there is significant value in exploring how we might collaborate moving forward. Please let me know if you would be available for a brief call at your earliest convenience.
After Sinceerly
human ✓Subtle
Human
CEO
How it worksOpen Gmail.Click the icon.01Write your emailDraft normally. Use AI to write the first version, or write it yourself. Doesn't matter.02Click the iconThe Sinceerly panel appears inside your compose window. Hit humanize.03Review & replaceYellow highlights show every change. Approve and replace with one click.
PricingSimple. No surprises.Free$0forever
3 free email rewrites
All three intensity levels
Works inside Gmail compose
Yellow change highlights
Add to ChromePro most popular$4.99per month
Unlimited rewrites
All three intensity levels
All 3 levels run in parallel, switching is instant
Cached results so reopening is instant
Get ProBring Your Own API Key (BYOK)
Have an Anthropic API key? Use it directly in the extension settings. Your email text never touches our servers. Every call goes straight from the extension to Anthropic. Pay only for what you use.
Built to keep your emails yours.
✓All requests sent over HTTPS. Emails are never stored.
✓We don't log or retain your email content.
✓BYOK API keys stay in your browser only.
Window 2 - Human
✓We only see the text you choose to humanize.
Hi, I'm Ben.I got sick of everyone in my inbox sounding like AI.So I built Sinceerly.I tested Sinceerly by cold emailing 5 Fortune 500 CEOs.4 CEOs replied. Of those replies, each was under 10 words. 2 replies had typos. One reply called me Larry (my name is Ben).LMK what you think.
Tue Apr 21 15:44:14 UTC 2026