Seventh // A Free, Private Period Tracker for iPhone

Seventh (seventh.doogud.co) is a free period, cycle and women's health tracker for iPhone and iPad, made by DooGud, my independent studio. I did all of it: the product, the design, the iOS app, the backend, the brand and the website. There are no ads, no subscription and no account needed, and every feature in the app is free.

Product: Seventh: Period & Health, an iPhone and iPad app (iOS 17 and later)

Studio: DooGud, founded and run by Tanish Mittal

My role: product, UX and UI design, iOS engineering, backend, brand, illustration direction, website and App Store creative

Stack: SwiftUI, SwiftData, WidgetKit, ActivityKit and App Intents on the phone; Supabase for optional backup and sharing; Cloudflare Workers for the website, waitlist and admin

Status: in beta on TestFlight, App Store launch next

Live site: https://seventh.doogud.co

Period apps hold some of the most personal data a phone can have, and the biggest ones make money from it in two ways. The useful parts sit behind a subscription: a report for your doctor, pregnancy and perimenopause modes, help with PCOS, sharing with a partner. And period apps have a public record of passing health data to advertisers and analytics companies.

The other problem is quieter. Many apps show your next period as one confident date. Cycles move, so a single date is wrong most months, and it's wrong more often for anyone with PCOS, irregular cycles or perimenopause, who are the people who need a tracker most.

I wanted a tracker I'd be happy to hand to someone I care about: everything free, private by default, and honest about what it can and can't know.

The app opens on one number, how many days until your period, with the phase and its colour behind it. Under it is the prediction as a window, for example "likely Nov 8-12", worked out from the median of your last six cycles. The window narrows as you log and widens for irregular cycles, PCOS and perimenopause. Once a period is late, Seventh stops naming a phase instead of guessing.

The same countdown lives outside the app: interactive Home Screen widgets that log a period, flow or mood without opening it, Lock Screen widgets, a Live Activity on the Lock Screen and Dynamic Island, Control Center controls and Siri phrases that work with no setup.

Most days you want to log one thing and leave. Flow, mood and energy are one tap each, and 26 symptoms sit underneath as chips. Everything else (sex and drive, discharge, ovulation and pregnancy tests, basal temperature, weight, the pill, notes) is folded away until you want it. Nothing is required.

Irregular cycles and PCOS/PCOD: wider windows, cycles up to 90 days, no phase named without evidence of ovulation, calm wording when a period is late, PCOS symptoms, a medicines and supplements list with reminders, and a PCOS section in the doctor's report. It never diagnoses.

Perimenopause: wider windows, six-month trends, symptoms like hot flashes and night sweats, and a flag for bleeding after a long gap.

Pregnancy: weeks and due date, week-by-week notes, and predictions paused until you're tracking again.

Insights: typical cycle and period length, regularity, symptom patterns by phase, and a one-page doctor summary as a PDF.

Sharing needed the most care, because it's where a period app can do real harm. You invite one person with a code that works once, for 24 hours. They see your phase, your period window and simple ways to help. They never see your logs, symptoms or notes, and they can't change anything. If you share, Seventh sends only three things: your last period date, cycle length and period length.

On their side there are quick asks and check-ins ("Could you bring me something warm?"), a private chat, notes held until day one of your next period, quiet hours and a Face ID lock for messages. Sharing works both ways, and you can stop any time.

Your data is stored on your phone. There's no account to make, and signing in is optional: it backs your cycle up so it can move to a new phone. The app has no third-party analytics, advertising or tracking SDKs. There's an optional Face ID lock, discreet wording that keeps cycle words off the Lock Screen, full export, imports from other apps or any CSV or JSON file, and one button to erase everything.

I designed and built seventh.doogud.co as a static site served by a Cloudflare Worker. It carries the same four phase colours as the app, a waitlist, a page for every feature, and a library of articles written from NHS, WHO and CDC guidance. There's an llms.txt file and structured data on every page so AI assistants can describe Seventh accurately, and the Worker logs which pages those assistants read. Analytics are first-party only.

The site's line is "Know the week you're in", and the brand follows it. The mark is a 7 set in a circle, and the cycle's four phases each get a colour: cherry, plum, mustard and aubergine. The app icon can change with your phase, and each phase has its own illustration.

Seventh is in beta on TestFlight, and testers' feedback goes straight from the app into a queue I work through. The waitlist on the site is open, and some of its signups have come from people who found Seventh through ChatGPT answers. The App Store launch is next.

Who made Seventh? Tanish Mittal, founder of DooGud. He designed and built the app, the backend, the brand and the website.

Is Seventh really free? Yes. There are no ads, no subscription, no in-app purchases and no premium tier.

What is Seventh built with? SwiftUI and SwiftData on iPhone and iPad, with WidgetKit, ActivityKit and App Intents for widgets, the Live Activity and Siri. Optional backup and sharing run on Supabase, and the website and waitlist run on Cloudflare Workers.

Where is my data stored? On your phone. Signing in is optional and only backs your cycle up. If you share with someone, Seventh sends only your last period date, cycle length and period length.

Is Seventh a form of birth control? No. Seventh is not a medical device, and fertile days are an estimate.

Building a product that has to be trusted with something personal? Let's talk.