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

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 robust 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. At $2.99/mo, it’s the only tracker that provides architectural privacy without sacrificing cross-device continuity.

Verdict

Euki wins on architectural privacy: on-device only, no account, no server exposure. Clue wins on features, cross-device sync, and polish. If you're in a state with abortion restrictions and want structural protection, Euki (free) or Floriva ($2.99/mo with sync) provide it. If cross-device sync matters and you're comfortable with GDPR-level server privacy, Clue is the cleanest server-based option.