Flo vs Euki: Mass Market Data Broker vs Privacy-First App

Flo settled a $59.5M class action for sharing your reproductive health data. Euki is free, on-device, and backed by a nonprofit. Here's how they compare.

Flo is the most-downloaded period tracker and faced FTC enforcement action for sharing user health data with Facebook and Google, a combined $59.5M class action resolved in September 2025. Euki is free, stores data only on your device, and requires no account. The feature gap between them is narrower than most people expect.

The download numbers tell one story; the FTC enforcement action tells another

Flo is the most-downloaded period tracker in the world. Its prediction algorithms benefit from the largest dataset in the category. Its feature set is genuinely comprehensive.

The FTC also took enforcement action against Flo in 2021 for sharing users' reproductive health data with Facebook, Google, and Flurry without consent. A class action over the same conduct settled for $59.5M in September 2025 (Reuters 2025-09-25). These are public facts from federal records.

Euki is a nonprofit-backed app with a fraction of Flo's downloads. Its UI is functional rather than polished. Its prediction accuracy is lower because it doesn't have Flo's dataset. It is also free, on-device, account-free, and has no documented history of selling user health data.

The feature gap is smaller than it appears

The common assumption is that private apps sacrifice features. Euki covers period tracking, fertile window prediction, sexual health education, contraception logging, STI information, and pregnancy tracking. It runs on both iOS and Android.

The gaps compared to Flo are real but narrower than expected: Flo's predictions are more accurate (more training data), Flo has cross-device sync (Euki doesn't), and Flo has a more polished interface. If those things matter more than the documented data violations, Flo is a functional choice. If they don't, Euki covers the essential use case at no cost.

The cross-device problem

Euki's main practical limitation is the lack of sync. Your data lives on your phone. If you get a new phone or use a tablet, starting over is the only option (manual CSV export aside). Flo handles this through cloud sync, which requires the server-side architecture that creates the subpoena risk.

Floriva's opt-in encrypted sync addresses this: data is encrypted on your device before transmission, so the sync infrastructure cannot access plaintext health data. The encryption key stays with you.

Cost and the nonprofit model

Euki is free because the National Institute for Reproductive Health funds it through grants and donations. There is no subscription, no ads, no freemium upsell. Flo's free tier is ad-supported and limited; full privacy requires paying for Anonymous Mode. Floriva is a paid app with no free tier; plans are shown in the app.

Cited signals

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

Flo vs Euki vs Floriva: Feature and Privacy Comparison

Feature	Floriva	Flo	Euki
On-device storage	Yes	No	Yes
Account required	No	Yes	No
Data can be subpoenaed	No	Yes	No
FTC enforcement history	No	Yes (2021)	No
Cross-device sync	Yes (E2E encrypted)	Yes (cloud)	No
iOS + Android	Yes	Yes	Yes
Free tier	No	Yes	Yes
Price	Paid app (no free tier)	Free / $4.99/mo	Free

Strengths and trade-offs

Floriva

Pros

On-device storage like Euki
Opt-in encrypted cross-device sync
No account required for local use
Privacy architecture without sacrificing continuity

Cons

Paid subscription required, not free
Newer with smaller prediction dataset

Flo

Pros

Largest dataset means better prediction accuracy
Feature-rich free tier
Cross-device sync and cloud backup

Cons

FTC enforcement action, sharing health data (2021)
$59.5M class action resolved (2025)
Anonymous Mode costs extra
Server-based with subpoena exposure

Euki

Pros

Free, no subscription, no ads
On-device only, nothing on servers to hand over
No account required
Broad reproductive and sexual health coverage

Cons

No cross-device backup or sync
Less accurate predictions vs Flo's larger dataset
UI less polished

Quick answers to the obvious questions.

Did Flo Health sell period data?

The FTC found that Flo shared users' reproductive health data, including period dates, pregnancy status, and health symptoms, with Facebook, Google, and the analytics firm Flurry. This sharing occurred despite Flo's privacy promises to users. The FTC took enforcement action against Flo in 2021. A combined class action settlement of $59.5M was reached in September 2025 (Reuters 2025-09-25). Flo's Anonymous Mode was introduced after the enforcement action but requires a paid subscription and does not change the server-based architecture.

Is Euki period tracker safe?

Euki is one of the safest period trackers available based on its architecture and track record. It stores all data on your device with optional encrypted sync support, requires no account, has no ads, and is backed by a nonprofit (National Institute for Reproductive Health) with no commercial data incentives. Euki has no documented FTC enforcement history. The main practical limitation is the lack of cross-device sync, if you lose your phone, your data is gone unless you've made a manual local export.

What is better than Flo for privacy?

Euki (free) and Floriva (paid, no free tier) both offer stronger privacy protection than Flo through on-device architecture, no account required, no server storage, nothing to subpoena. Clue is the strongest privacy option among commercial server-based trackers, with GDPR compliance and no documented enforcement history. Drip (Android) is open source and on-device. Any of these is a stronger privacy choice than Flo.

Questions people ask before they switch.

What happened in the Flo FTC case?

In January 2021, the FTC took enforcement action against Flo Health, Inc. over allegations that Flo shared users' health data, including menstrual cycle dates, pregnancy status, and symptoms, with third-party analytics services including Facebook SDK and Google Firebase Analytics despite promising users that such information would remain private. The FTC case is documented at ftc.gov/cases-proceedings/192-3133-flo-health-inc.

Can I switch from Flo to Euki?

You can start using Euki at any time, no import from Flo is required to begin tracking. If you want to preserve your historical Flo data, Flo allows data export (CSV format) which you can keep as a personal record, though Euki doesn't currently import it. Your future tracking data with Euki stays on your device.

Does Euki track pregnancy?

Yes. Euki covers pregnancy tracking in addition to period cycles, sexual health, contraception logging, and STI information. It is broader in scope than its minimal UI might suggest. Euki is developed by the National Institute for Reproductive Health, which means reproductive health coverage is part of the core mission.