Euki vs Clue: On-Device Privacy vs GDPR Server Tracker

Euki is free, on-device, and requires no account. Clue is GDPR-compliant and feature-rich but stores data server-side. Here's what that difference means.

Euki stores data only on your device, requires no account, and is free, no ads, no data selling. Clue is GDPR-compliant and has a better enforcement record than Flo, but requires an account and server-side storage. Euki's on-device architecture provides structural protection Clue cannot.

The core choice: architecture vs features

Euki and Clue represent different answers to the question of what "private period tracker" means.

Euki answers it architecturally: no data leaves your device, no account is required, there is nothing to hand over. The privacy is enforced by what the app doesn't do.

Clue answers it through policy: GDPR compliance, transparent data practices, no ad-supported model, no documented enforcement history. The privacy is enforced by what the company has committed not to do.

Both approaches have real value. The difference matters when the threat model is legal compulsion rather than commercial data misuse.

What on-device storage actually prevents

When Euki stores your period data on your device, a court order served on Euki produces nothing. Euki doesn't have your data. This is the structural advantage of on-device architecture.

With Clue, a court order served on Clue could compel them to produce your data. GDPR provides protections for EU-based legal requests. US legal requests, depending on jurisdiction and data-sharing arrangements, may or may not be subject to those protections. The data exists; the question is whether it can be compelled.

In states with abortion restrictions, prosecutors have sought digital evidence. Period tracker data has been discussed as potential evidence in such proceedings. For users in those states, the distinction between "company promises not to share" and "company has nothing to share" is meaningful.

Where Clue has the edge

Clue's free tier is better than most: no ads, cross-device sync, solid cycle prediction, and a clean enforcement record compared to Flo. If you need cross-device backup and you're comfortable with GDPR-level server privacy (which is genuinely strong for commercial data use), Clue is the strongest server-based option in the category.

Closing the gap

Floriva was built specifically to close the gap between Euki and Clue: on-device storage by default, with opt-in end-to-end encrypted sync for users who need multiple-device access. The sync uses keys Floriva doesn't hold, the data is encrypted on your device before it's transmitted. As a paid app with no free tier, it's the only tracker in this comparison that combines on-device architecture with opt-in encrypted cross-device sync. Euki has the privacy without sync, Clue has sync without the privacy architecture.

Definitions

On-device storage: A storage model where data is saved locally to the user's phone or tablet and never transmitted to a remote server. There is no company-held copy of the data, which means no subpoena surface and no breach exposure from company servers.
End-to-end encryption: A communication method where data is encrypted on the sender's device and can only be decrypted by the recipient. Intermediate servers handle only ciphertext and cannot read the content. For sync in period trackers, E2E encryption means the app developer cannot read your health data even if they hold encrypted copies on their servers.

Cited signals

Euki is free with no subscription, no ads, and no in-app purchases Ibis Reproductive Health (Euki developer)
Flo Health paid a $59.5M combined settlement for sharing reproductive health data without user consent Reuters / FTC, September 2025

Euki vs Clue vs Floriva: Privacy Architecture Comparison

Feature	Floriva	Euki	Clue
On-device storage	Yes	Yes	No
Account required	No	No	Yes
Data can be subpoenaed	No	No	Yes
Cross-device sync	Yes (E2E encrypted)	No	Yes
GDPR compliant	N/A, no server data	N/A	Yes
FTC enforcement history	No	No	No
Price	Paid app (no free tier)	Free	Free / $9.99/mo
Ad-supported	No	No	No

Strengths and trade-offs

Floriva

Pros

On-device storage like Euki, with sync like Clue
No account required for local use
Opt-in encrypted sync bridges the gap

Cons

Paid subscription required, not free
Newer, smaller track record than Euki

Euki

Pros

Free, no ads, no data collection of any kind
On-device only, no subpoena risk
Broad coverage including sexual health topics
iOS and Android

Cons

No cross-device sync, data lost if phone is lost
UI less refined than commercial apps
Feature velocity slower than VC-backed competitors

Clue

Pros

Strongest privacy track record among major commercial trackers
Ad-free even on free tier
Cross-device sync with cloud backup

Cons

Server-based, account required, subpoena risk exists
GDPR protects against commercial misuse, not legal compulsion
Full features behind paywall

Quick answers to the obvious questions.

Is Euki better than Clue for privacy?

Euki provides stronger architectural privacy than Clue. Euki stores data only on your device, there is no server to subpoena. Clue is the best commercial tracker for privacy with its GDPR compliance and clean enforcement record, but GDPR does not prevent law enforcement from obtaining data via court order. For users in states with abortion restrictions, on-device storage is the structurally safer option.

Does Euki have a web version or desktop app?

No. Euki is a mobile app for iOS and Android only. There is no web version, and because data stays on-device, there is no account-based access from a browser. This is a feature of its privacy model, not a gap, but it does mean Euki is phone-only.

Why is Euki free?

Euki is developed and maintained by Ibis Reproductive Health, a nonprofit. The app is funded through nonprofit channels rather than advertising or data monetization. That is why Euki can be free with no ads and no data selling. Its business model does not require monetizing user data.

Questions people ask before they switch.

Can Euki data be used in court?

Euki stores data only on your device. A subpoena to Euki would return nothing, there is no server holding your data. However, a court could potentially compel you or law enforcement could seize your device. The key distinction is that on-device-only apps remove the easiest legal access point: a subpoena to the company.

Does Clue share data with third parties?

Clue's GDPR compliance substantially limits commercial data sharing. Clue has not faced FTC enforcement actions like Flo or Premom. Clue's privacy policy outlines specific data sharing practices for service providers and research partnerships with user consent. Users should review Clue's current privacy policy at clue.plus for specifics. The key technical limitation remains: data is server-side and technically accessible via legal process.

What is the best free period tracker that doesn't require an account?

Euki is the most feature-complete free period tracker that requires no account and stores data on-device. Drip (Android only) is another free, no-account option that is also open source. Both are genuinely private by architecture. Floriva is a paid app with no free tier and adds cross-device encrypted sync that neither free app provides.