# Synca vs Red Diary

The clearest difference is monetization model: Red Diary at freemium against Synca's subscription. Red Diary also leads on update cadence (every 3 days vs every 2 weeks) and ratings volume (9 vs 2). On price, rating, review sentiment and ads there is nothing between them.

Both are free to download. Synca sells 2 in-app purchases, starting at $4.99 per month and Red Diary sells 2 in-app purchases, starting at $0.99 per month. Whichever you choose, the download price is not the number that matters.

On the App Store both sit at effectively the same score — 5.0 for Synca against 5.0 for Red Diary. Both are backed by a comparable volume of ratings — 2 and 9 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

Synca ships an update every 2 weeks, Red Diary every 3 days. The most recent releases landed on September 29, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Synca | Red Diary |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (2 ratings)](https://appshunter.io/ios/app/synca-ai-cycle-syncing/id6758351599/reviews) | [5.0 (9 ratings)](https://appshunter.io/ios/app/red-diary-period-tracker/id6767368239/reviews) |
| Number of ratings | 2 | **9** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Every 3 days** |
| Monetization | Subscription | **Freemium** |
| Size | 25 MB | 8 MB |
| Requires iOS | **17.0** | 17.6 |
| Devices | iPhone | **iPhone, Apple Watch** |
| Age rating | 4+ | 12+ |
| Developer | [Burcu Ibicioglu](https://appshunter.io/developer/1872466864) | [RUBINS DORMEUS](https://appshunter.io/developer/1884865930) |

## What reviewers say

### Synca

[App page](https://appshunter.io/ios/app/synca-ai-cycle-syncing/id6758351599)

This app uses AI to help you plan your daily tasks and activities around your menstrual cycle. It provides personalized insights and suggestions for energy, focus, and mood based on your current cycle phase. Optimize your productivity and well-being by working with your body's natural rhythms.

**Highlights:** AI-powered cycle-aware task planning, Personalized daily insights based on cycle phase, Four cycle phases with identified strengths, Smart calendar with energy-based event tagging, Quick daily mood and energy tracking, Phase-matched workout and meal suggestions, Private data storage on device

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Synca AI | $4.99 | per month |
| Synca AI | $24.99 | per year |


### Red Diary

[App page](https://appshunter.io/ios/app/red-diary-period-tracker/id6767368239)

This app analyzes your symptoms, mood, energy, sleep, and activity to provide personalized insights and daily guidance tailored to your cycle phases. It offers a body weather forecast and smart recommendations for exercise, nutrition, and self-care.

**Highlights:** Personalized cycle insights, Smart daily guidance, Body weather forecast, Cycle tracking modes (fertility, pregnancy, birth control), Symptom and mood logging, HealthKit integration, Apple Watch companion app

**Features:** macOS Compatibility, Apple Watch app

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Monthly | $0.99 | per month |
| Premium Annual | $4.99 | per year |


## Frequently asked questions

### Is Synca free?

Synca is free to download, with in-app purchases available.

### Is Red Diary free?

Red Diary is free to download, with in-app purchases available.

### Which has better reviews, Synca or Red Diary?

Synca and Red Diary are both rated 5.0 out of 5 on the App Store, from 2 and 9 ratings respectively.

### Do Synca or Red Diary have ads?

Neither Synca nor Red Diary shows ads.

### Which is updated more often, Synca or Red Diary?

Synca ships an update every 2 weeks, and Red Diary every 3 days. Most recently, Synca was updated on September 29, 2026 and Red Diary on October 1, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*