TLDR
Clue is meaningfully better than Flo on privacy history. Flo has a documented FTC enforcement action (2021) and a $59.5M class action settlement (2025). Clue is GDPR-compliant with no documented violations. But both store your data on servers. If that architectural risk matters to you, neither Flo nor Clue solves it.
| Factor | Flo | Clue | Floriva |
|---|---|---|---|
| Data location | Flo servers | Clue servers | Your device only |
| Account required | Yes | Yes | No |
| FTC enforcement history | Yes (2021) | No | No |
| Class action settlement | $59.5M (2025) | None | N/A |
| GDPR compliance | Yes | Yes | N/A (no server data) |
| Subpoenable | Yes | Yes | No |
| Anonymous Mode | Paid only | No | Default for all users |
| Monthly cost | Free / $4.99 | Free / $9.99 | $2.99 |
- Zero-knowledge storage
- A data storage model where the service provider holds only encrypted data they cannot read. The encryption keys never leave the user's device. Even if the company is subpoenaed, they can only produce ciphertext that is useless without the user's key.
DEFINITION
- 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.
DEFINITION
Flo vs Clue: the short answer
If you are asking which app is safer for privacy, the answer is Clue. Flo carries the FTC enforcement action from 2021 and the later settlement history tied to reproductive-health data sharing. Clue does not. That alone is enough to separate the two.
That does not make Clue private in the way many people mean it. Clue still requires an account and still keeps your cycle history on company servers. So the real answer is two-part: Clue is safer than Flo on trust history, and neither app gives you architecture-level protection from a company-side data request.
Where Flo and Clue still look the same
Both apps depend on cloud storage. Both ask you to create an account. Both keep records that the company can access and maintain. If the issue you care about is whether the company has a copy at all, Flo and Clue land in the same bucket.
GDPR helps Clue on the commercial-use side. It does not turn cloud storage into local storage. A cleaner policy framework is still a policy framework. If you want to reduce company-side exposure, you need an app that keeps the data on the device and skips the account requirement.
The Anonymous Mode Problem
Flo introduced Anonymous Mode after the FTC enforcement action. This feature limits how much of your activity is tied to your account. It requires a paid subscription, which means that at Flo’s free tier, the version used by the majority of users, the privacy protections are lower.
Clue does not offer an equivalent anonymous mode. The GDPR protections are automatic, but they apply to commercial data use, not to the account linkage itself.
Both approaches treat privacy as a feature layered on top of a cloud-based architecture. On-device trackers treat privacy as the baseline architecture.
Pricing Side by Side
Flo’s free tier is ad-supported. Premium is $4.99/mo or $39.99/yr. Anonymous Mode requires premium. Clue’s free tier has no ads but limits feature access. Plus is $9.99/mo or $59.99/yr. Floriva is $2.99/mo with on-device storage as the default, not a paid add-on.
Neither feels private enough?
The Floriva app stores everything on your device. No data sold, no account required.
See plans & pricingVerdict
Clue is the safer pick if you are choosing only between Flo and Clue. Flo carries the FTC case and settlement history. Clue does not. But both apps keep data on company servers, so neither solves the core subpoena problem.
PROS & CONS
Flo
Pros
- Strong cycle prediction, large dataset
- Comprehensive feature set
- Wide platform support
Cons
- FTC enforcement action (2021)
- $59.5M class action (2025)
- Server data, subpoenable
- Privacy features cost extra
PROS & CONS
Clue
Pros
- No documented enforcement actions
- GDPR jurisdiction
- No ad-supported model
Cons
- Server-side storage
- Account required
- GDPR is policy, not architecture
- Premium required for full features
PROS & CONS
Floriva
Pros
- On-device storage, structurally unsubpoenable
- No account required
- Default privacy for all users, no paywall
- $2.99/mo flat
Cons
- Smaller feature set than established apps
- No automatic cloud backup
Q&A
Is Clue safer than Flo for period tracking?
Clue has a cleaner privacy history than Flo. The FTC took enforcement action against Flo in 2021 for sharing user health data with Facebook and Google without consent. Clue has no comparable enforcement history and operates under GDPR from Berlin, which provides stronger commercial privacy protections. Between the two, Clue is the better choice on privacy history.
Q&A
Can Flo or Clue data be used against me in court?
Both Flo and Clue keep user records on company servers. That means both can be ordered to produce data if a court with jurisdiction asks for it. Flo's FTC history makes the trust question more urgent, but the technical exposure is the same for both apps. The only trackers that remove that company-side risk are the ones that never create a server copy in the first place.
Q&A
What period tracker is completely private?
The most private period trackers are those that store data only on your device: Floriva (iOS and Android, $2.99/mo), Euki (free, nonprofit), and Drip (free, Android only). None require an account. None transmit your data to company servers. None can be subpoenaed for your data because the data never leaves your device.
Q&A
Does Clue sell your period data?
Clue does not have a documented history of selling user data the way Flo does. Clue is GDPR-compliant and Berlin-based. However, Clue still requires an account and stores data server-side, which means it can be accessed via court order or government request. GDPR compliance limits commercial data sharing but does not prevent law enforcement access.
Q&A
Is Flo or Clue safer for privacy?
Clue has a cleaner privacy track record than Flo. Flo faced FTC enforcement action in 2021 for sharing sensitive health data with Facebook and Google without user consent, then faced a $59.5M class action settled in September 2025. Clue's GDPR compliance provides stronger data protection in the EU context. That said, both apps require server-side storage, so neither provides architecture-level protection against subpoenas.
Q&A
Which period tracker keeps data only on your phone?
Floriva stores all cycle data exclusively on your device using encrypted local storage. No account is required and no data is transmitted to company servers, which means there is nothing to subpoena. Drip (Android) and Euki also use on-device storage as their default architecture.
Source: Reuters / FTC, September 2025
Source: Flo Health pricing
Source: Clue pricing page
Frequently asked