Advertising for our own product: this comparison is published by icoso consulting S.L., the company behind Luna. We compare selected features using the sources given; statements about Luna are our own, statements about other apps come from their own publications.
Luna, Clue, drip and Euki are alternatives to Flo. The table compares them with Flo on selected privacy features: where the data is stored, whether it syncs, whether registration is required and which trackers are known. Luna encrypts tracking and journal content on your device with AES-256 before sending it to our EU servers. Certain medication, intake and administrative details remain readable and may reveal information about your health. In Standard mode, Luna can recover the encryption key. See section 4 of our Privacy Policy. According to its project page, drip keeps entries on your device. Euki states that it does not collect personal data. The sections below the table say when which app is the better fit.
✓ = yes · ✗ = no · “not assessed” = we deliberately make no claim here — please check directly with the provider.
| Luna | Flo | Clue | drip | Euki | |
|---|---|---|---|---|---|
| Open source | ✗¹ | partly (Anonymous Mode libraries) | not assessed | ✓ | ✓ |
| Entries stored only on the device | ✗ | ✗ | ✗ | ✓ | not assessed |
| Sync across devices | ✓ | ✓ outside Anonymous Mode; no cross-device sync in Anonymous Mode⁴ | not assessed | ✗ | not assessed |
| Registration required | ✓ | optional according to the Privacy Policy; restrictions apply in Anonymous Mode⁴ | not assessed | not assessed | not assessed |
| Server and processing locations according to the provider | App servers and database: Finland, EU; see the list for other providers | US and other countries according to the Privacy Policy⁴ | EU data hosting; other transfers described in the Privacy Policy⁴ | According to the project page, entries stay on the device; other processing not assessed here | not assessed |
| Entry content encrypted on device and stored as ciphertext on the server | ✓ AES-256; see exceptions for readable data above | not assessed | not assessed | n/a² | not assessed |
| Zero-knowledge option for encrypted entry content | ✓ Maximum Privacy; excludes readable metadata and optional AI processing | not assessed | not assessed | n/a: entries stay local | not assessed |
| Result of the linked Exodus analysis | Android 1.3.1: one detected tracker signature, Sentry (crash reporting); no detected advertising-tracker signature (report)³ | check yourself | check yourself | check yourself | check yourself |
| Life phases covered | Cycle, pregnancy, breastfeeding, perimenopause and menopause; fertility-treatment documentation with Luna Plus | Cycle and pregnancy tracking; logging perimenopause and menopause symptoms (Privacy Policy)⁴ | Cycle tracking (Privacy Policy); other modes and their subscription requirements not assessed here⁴ | focus on cycle | Period and pregnancy tracking; sexual and reproductive health information |
| Price model | free basics + subscription/pass | not assessed | not assessed | not assessed | free |
¹ Publishing the encryption layer is planned (after the US launch), no date promised.
² According to drip’s project page, entries stay on the device, so encryption before upload to a provider server does not apply.
³ Exodus report dated 30 July 2026 for Android 1.3.1. Static signature analysis; it does not establish all trackers, their activity or results for other app versions.
⁴ Source snapshot for the Flo and Clue statements marked ⁴: 11 August 2026. These statements are based on the provider information linked in those cells. Features and terms may change.
Every claim about the Luna cycle app with its source
Both projects are open source. According to its project page, drip keeps entries on your device. Euki states that it does not collect personal data and is free without paywalls.
Luna is built for people who want to track cycle, pregnancy, breastfeeding and menopause in one app:
Many of these features exist in other apps too. Luna pairs them with EU hosting and on-device encryption, and it is funded by subscriptions, with no ad tracking and no data sales.
What to check with any app that uses servers is explained in our guide Period tracker privacy.
Whatever provider you choose — including Luna — check the server location, an independent tracker report and the privacy policy.
→ Every claim about the Luna cycle app with its source
Check where your data is stored and processed, which trackers are known for the app version examined, how the service is funded, and whether you can export and delete your data. This applies to Luna too.
“Not assessed” means that we do not make a substantiated comparison for this feature. It does not mean that the feature is absent or that the app is unsafe. This comparison is not an independent product test.
Yes, for anyone who wants a tracker with sync across devices, EU hosting, on-device encryption and no ad tracking. The table above shows the differences in detail, including where other apps are the better fit.