Flo alternatives
Period and cycle tracker with predictions and symptom logging.
6 of its 6 core features can be rebuilt with AI. Here is one, working, below.
- They makeRevenue estimate on Sensor Tower
- $7M a month
- You pay
- $60 a year
- AI can rebuild
- 6 of 6 core features
Try it
Visual demo only. Copy the prompt below to get the app.
Build it yourself
Real files on your machine, a real database, and it is yours. This one carries the interface as well — the layout, the colours and the shape of the real app, read off its own screens.
Each opens with the prompt loaded and waiting — nothing is sent until you press enter. It is copied at the same time, in case the app is not installed.
Build me a local period tracker I own, to replace Flo. - A web app I run on my own machine: a single Node process serving one page, data in a SQLite file next to it. - Log period days on a calendar. Store each logged day as its own row so I can correct history later. - Derive predictions from my logged data only: mean and standard deviation of cycle length, next period date with a range rather than a single day, and a fertile window from the luteal-phase estimate. - Symptom logging from a fixed list plus a free-text note, one row per day. - A history page: every cycle with its length, a chart of cycle length over time, and my variability. - Export everything to CSV and JSON with one command. - Runs on localhost only. No accounts, no telemetry, no network calls at all. This is health data and it never leaves the machine. - Skip: a mobile app, partner sharing, and any content library. - Include a README with how to start it, where the database lives, and how to back it up. Put a line in the interface saying predictions are estimates and not contraception. ## Look and feel Flo's own — soft pink and rose on white, very rounded shapes, the calendar the centrepiece, gentle rather than clinical. Generous spacing, clear hierarchy, big tap targets, phone-readable type, system font. Keep the text dark enough to read at a glance: the softness of a palette belongs to the shapes and the fills, never to the words. Nothing I need to read — dates, numbers, labels — in pale grey on white.
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Feature by feature
Every feature, whether AI can rebuild it, and what you would be signing up to keep running if you did. The paid app does that last column for you, and that is most of what the money buys.
| Feature | Core | AI can rebuild | You'd maintain |
|---|---|---|---|
| Period logging | Yes | Yes | Nothing |
| Next-period prediction | Yes | Yes | Nothing |
| Fertile window and ovulation estimate | Yes | Yes | Nothing |
| Symptom and mood logging | Yes | Yes | Nothing |
| Cycle history and averages | Yes | Yes | Nothing |
| Calendar view | Yes | Yes | Nothing |
| Health content libraryWritten and reviewed by people. An AI can write something similar, but not something reviewed. | No | No | You would write it |
| Anonymous communityOther people are the feature. | No | No | You would need the people |
| Partner sharing | No | Partly | You would build the sharing |
What you give up
- articles written and reviewed by actual clinicians
- the anonymous community
- an app on your phone that works with no signal
- predictions tuned on millions of cycles rather than only yours
Why people still pay
The maths is simple arithmetic on your own data. What people are paying for is the reassurance of an app that looks medical, and somewhere to ask a question at 1am.
Or use one somebody already built
Free and open source. No prompt, no building, no subscription.
- drip.
- A cycle tracker that keeps everything on your device. Built specifically so nobody else holds the data. (ios, android)
- Periodical
- A plain, offline period calendar with predictions and no accounts. (android)
Other apps people are freeing
Questions
- Can AI really replace Flo?
- 6 of its 6 core features, yes. The demo above is what one prompt produced. What it cannot do is on this page too.
- What does Flo cost?
- About $60 a year on the Flo Premium plan. Logging and basic predictions are free. Insights and reports are paid.
- Is there a free alternative to Flo?
- Yes: drip., Periodical. They are listed below, and they are somebody else's finished work rather than yours.