On the evidence available, yes — Euki is one of the two strongest privacy positions in the category. Its App Store privacy label declares “Data Not Collected,” meaning the developer declares it gathers nothing at all. It requires no account, email or phone number, and stores your data locally on your device. It is the only period app Mozilla named to its *Privacy Not Included “Best Of” category.

Does Euki require an account?

No. Euki states you don't need an account, email or phone number to use it. That matters more than it sounds: without an identifier, there is no straightforward way to associate a record with a person, and nothing to breach on a server.

What is Euki's fake screen feature?

Euki supports a customizable PIN, and entering 0000 shows a decoy screen rather than your real data. It is designed for the situation where someone else has your unlocked phone — a partner, a parent — which is a far more common threat than a subpoena and one most trackers ignore entirely.

Euki vs Dew — which is more private?

Euki, by the measure used in our index. Euki declares “Data Not Collected”; Dew declares “Data Not Linked to You” for Usage Data and Diagnostics, because Dew sends an anonymous, opt-out usage counter. Both keep cycle data off any server and neither requires an account, but Euki's declaration is the stricter one. This review is written by Dew's maker and that result is published as it stands.

What are Euki's downsides?

Because Euki stores everything locally and holds no account, losing or wiping your phone without your own backup means losing your history. Its prediction and insight features are also lighter than trackers that focus purely on forecasting — Euki is built as a reproductive-health resource with tracking included, not primarily as a prediction engine. Whether that's a downside depends on what you want from the app.

Is Euki safe? A look at the app that beat mine

I make a competing period tracker, and Euki scores better than mine. Here's an honest look at how it works and who it's for.

Short answer: yes. Euki holds one of the two strongest privacy positions in the category — its App Store privacy label declares “Data Not Collected,” it needs no account, and it stores everything locally on your device. It is the only period app Mozilla named to its *Privacy Not Included “Best Of” category.

A declaration of interest before anything else: I make Dew, which competes with Euki, and in my own Period Tracker Privacy Index Euki scores better than Dew does. Read this knowing that. I’d rather write it than have you find out from someone else.

What Euki actually is

Euki is a free, non-profit reproductive health app. That framing matters, because it explains most of the design decisions: it is not primarily a prediction engine with privacy bolted on, it is a reproductive-health resource that happens to include cycle tracking.

Alongside logging periods, symptoms, contraception, medication and appointments, it carries non-judgemental information on abortion, contraception, STIs and sex education, plus a care-navigator tool for finding providers. Most trackers would not touch that content. Euki was built for it.

The privacy position, specifically

App Store privacy label: “Data Not Collected.” Read from the listing on 23 August 2026. This is the strongest declaration Apple offers — it means the developer states it gathers nothing, of any kind. Only two of the fourteen apps in our index reach it.
No account. No email, no phone number, no sign-in. Nothing to link a record to a person.
Local storage. Data lives on your device, not on a company server.
PIN plus a decoy screen. A custom PIN protects the app, and entering 0000 shows a fake screen instead of your real data.

That last one deserves more credit than it usually gets. Almost all privacy writing in this category — mine included — is preoccupied with companies, subpoenas and brokers. For a great many people the realistic threat is far closer: someone who already has your unlocked phone. A decoy screen is a direct answer to a threat model most trackers pretend doesn’t exist.

Why the Mozilla badge matters

When Mozilla reviewed 25 reproductive health apps and devices, it applied its *Privacy Not Included warning label to 18 of them. Euki was the sole period app placed in the “Best Of” category.

It is worth understanding what that badge is doing now, beyond its original purpose. It made Euki the app that independent reviewers, journalists and — increasingly — AI assistants name when someone asks for a private period tracker. One credible third-party assessment did more for Euki’s visibility than any amount of self-description could. That is a fair outcome, and it is a fact about how trust propagates in this category.

The honest trade-offs

No app is free of them, and Euki’s follow directly from its strengths.

Local-only means you own the backup problem. No account and no server copy means that if you lose your phone without your own backup, the history is gone. This is the direct cost of the thing that makes it safe.
Prediction is not the focus. If what you want is a sharp forecast, temperature-informed ovulation estimates, or detailed cycle analytics, Euki is lighter than trackers built around that. It is a deliberate emphasis, not an oversight.
The information content is US-centred. Extremely useful if you’re there; less so elsewhere.

Euki or Dew?

Since I am obviously not neutral, let me be concrete instead.

Choose Euki if you want the strictest possible data position, if you want a decoy screen, or if the reproductive-health information and care navigator are useful to you. It declares that it collects nothing, and Mozilla has independently assessed it. That is a stronger claim than mine.

Choose Dew if what you want is a tracker — sharper predictions, cycle modes for the pill, an IUD, pregnancy or perimenopause, Apple Health sync, widgets and Live Activities, private iCloud backup so losing your phone doesn’t lose your history — with cycle data still never leaving your device. Dew declares an anonymous, opt-out usage counter, which is why it sits one tier below “Data Not Collected.”

And drip deserves a mention: also “Data Not Collected,” also no account, and open source — the source is publicly auditable, which is a stronger form of evidence than any declaration, including mine.

There is no version of this where I tell you the private-tracker category has one correct answer and it happens to be the app I sell. Three apps here take your privacy seriously in genuinely different ways.

Sources

Euki App Store listing and privacy label, read 23 August 2026
Mozilla Foundation — *Privacy Not Included, reproductive health app reviews
The Period Tracker Privacy Index — all 14 apps, verified 23 August 2026

Notes on this page

About the claims made here regarding other apps. Statements about what any third-party app collects are descriptions of that developer's own published declarations — its App Store privacy label, its published privacy policy, or a public regulatory filing — read on the date shown. They describe what a company has said, not an independent audit of its software, and they may be out of date if a developer has since changed its declaration. App names and trademarks belong to their respective owners and are used here for identification and comparison only; no affiliation or endorsement is implied or claimed.

Corrections. If anything here is inaccurate or has gone stale, please write to [email protected]. Substantive corrections are made promptly and noted on the page rather than quietly edited away.