Red Sabbath

TimeframeSpring 2020
collaborationTeam of 4
00. Overview

Red Sabbath is a period tracking app.... that is death metal-themed.

There are dozens of period tracking apps out there, but have you ever wondered why most of them are pink and flowery? Why is there no period app that is... bloody and brutal? Because that's how my periods are!

I found out that some of my friends were wondering the same thing. The spring break was coming as well, so we decided to make this crazy idea come true!

Haley Park, Gautham Sajith, Caitlin Coyiuto, Cora Wang
My role
Project manager, design lead
01. Research

Competitive Analysis

There are plenty of period tracking apps in the market. In order to define our app's scope and selling point, we downloaded existing period tracking apps and used it for ourselves. After studying the apps, we identified their strengths and weaknesses.

How do women track periods?

We conducted semi-structured interviews to learn how women track their periods.

We interviewed two groups of women - women who track periods with a mobile app and women who don't.
For women who track periods with a mobile app, we tried to understand what kind of apps they use, what they track, when they check the app, and the pain points that they experience.

For women who don't track periods with a mobile app, we tried to understand why they don't, what methods they currently use, and why they chose to use the method they use.

Insights & findings from the interviews

  1. People who use period apps to log their cycles often forget to log the end date.
  2. People who use period apps sometimes log cramps, flow (heavy, light), and anomalies.
  3. People don’t like other people seeing their sensitive information when the apps send notifications.
  4. People sometimes scroll through their period tracking apps to read the period-related information.
Why do I need to have flowers and bubbles and pink? That doesn't make me feel better at all.

Interview participant

02. Defining

Feature prioritization

From our interviews, we identified the features that we will incorporate in our app. Among the features, we decided on the essential ones to build in this round before getting it out into the world.


  1. See period predictions
  2. Log period
  3. Editing past periods
  4. Get notifications for period starting
To include in the future

  1. Export data
  2. iCloud sync
  3. States - birth control, pregnancy
  4. Health information
03. Branding

Making our app stand out

I carefully crafted the visual theme and identity, since the branding and tone were what was most distinct about our app.

03. Iterations

Lo-fi prototypes and iterations

We went through iterations with different fidelities and tested the prototypes after each stage. We used the whiteboard frequently to ideate together and fleshed out the flow.

Lo-fi iteration
Whiteboarding 2
Mid-fi iteration
Usability testing
Hi-fi iteration
Usability testing
04. Design

Main visualization

One of our app's primary functions is to give period predictions, so we spent a long time iterating and debating on the visualization on the home screen. It should be intuitive enough to communicate how far ahead is the next period.



Several popular period tracking apps use a round cycle to visualize periods.

While people who already use those apps are familiar with the cycle view, we found that it's often confusing for people because they couldn't differentiate the start of the last period and the next period.

Horizontal Bar

While this was more intuitive to read, the typical mobile device screen size was too narrow for horizontal bars.

Add period

From our interviews, we learned that people who use period apps typically log periods, level of flow, sometimes cramps or mood. We also learned that having a lot of options is often overwhelming in period apps.

We'll add more options as we move further, but we experimented with having three entries as MVP.

Users can also add multiple entries at once.


From our interviews, we learned that people who use period apps usually go to the calendar view page within their app to see their past periods.

We iterated on the calendar view to allow:

  • Viewing period and past log information at a glance
  • Editing period lengths as well as data in individual dates
  • Addding new data

05. Prototype

Prototype, test, and repeat

Due to the situations regarding COVID-19, We're testing our prototypes remotely via zoom & Figma.
We're still iterating on our hi-fi UI, so some of the screens are still in the works!

04. Design System

Blood Design System

I also started building a design system for our app. I documented the major decision decisions and standards, as well as making a single source of truth for all of our components.

05. reflection

What I learned so far

Design is [never done]

Products constantly evolve, and so does design. There is rarely a 100% right design decision, so I got used to the idea of constantly building, failing and experimenting.

Design is [a conversation]

A critical process in design is debating every design decision with your team and bringing everything on to the floor.

Design is [making decisions]

In a lot of cases, there are several different ways to design the littlest feature. A good designer has to evaluate each options, make the best decision, as well as clearly communicating her design decision.

Plans for next steps

  • We'll conduct another round of usability testings and start finishing up the flow.
  • After that, I'll get down to polishing every bit of the design, including making our own icon set.
  • After that, we'll finish up the data structure and start implementing the designs in detail.
  • Once we have the running app, we're planning to run beta testing before releasing our app.
  • We're planning to release our app to the app store!

Shoutout to my amazing team!

Even though we had to work on this project on top of all of our coursework and the global pandemic looming over us, we were able to accomplish so much over such short period of time. I had so much fun and I'm grateful for my teammates who joined me in this weird project.

I'll be updating this page as we move further! Stay tuned ✨