Discover Boring Businesses that Quietly Rake in the Cash

Million-Dollar Online Diary App


Penzu is a free online diary and personal journal app that prioritizes privacy.


The Team

Penzu was launched in 2009 by Alexander Mimran.


Business Model & Revenue

Penzu uses a freemium business model. This means there is a free basic plan with limited features, and paid pro plans with more features.

The free plan includes unlimited entries, mobile apps, basic journal covers and fonts, and simple writing reminders. The paid pro plans offer additional features such as encryption locking, custom journal covers, fonts and colors, entry tagging, PDF export, writing prompts, writing via email, premium handwritten fonts, fullscreen zen mode, versions & entry recovery, and premium support.

According to Kona Equity, Penzu's annual revenue is $2,194,000, with only 8 employees.



Penzu's main traffic comes from direct users who already know the brand and returning users.

The secondary channel is Google search.


Tech Stack

  • Backend: Ruby on Rails

  • Frontend: jQuery, AngularJS

  • Server: Ubuntu, Nginx

  • App: Objective-C, Java

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