# SoStack vs Polymemo

The clearest difference is in-app purchases: SoStack at none against Polymemo's 5. Polymemo's advantage is update cadence (every 2 days vs every 3 weeks). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Polymemo sells 5 one-off in-app purchases. SoStack asks for nothing beyond the download.

SoStack ships an update every 3 weeks, Polymemo every 2 days. The most recent releases landed on October 10, 2026 and October 4, 2026 respectively.

## The numbers

| Metric | SoStack | Polymemo |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (3 ratings)](https://appshunter.io/ios/app/sostack/id6759353874/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 2 days** |
| Monetization | Free | — |
| Size | 43 MB | 71 MB |
| Requires iOS | 15.1 | **15.0** |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 12+ | 17+ |
| Developer | [SOSTACK LIMITED LIABILITY COMPANY](https://appshunter.io/developer/1878252494) | [Polymemo Inc.](https://appshunter.io/developer/1891623284) |

## What reviewers say

### SoStack

[App page](https://appshunter.io/ios/app/sostack/id6759353874)

This app facilitates group communication and coordination with private chats and shared calendars. Plan events, manage RSVPs, and discover local public groups for updates. It prioritizes user control and privacy with in-app account deletion.

**Highlights:** Private group messaging, Shared calendars and events, RSVP and planning tools, Follow verified public groups, Invite via SMS, Location-based discovery

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Polymemo

[App page](https://appshunter.io/ios/app/polymemo/id6761815373)

**Features:** macOS Compatibility

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 500 Points | $4.99 | one-time |
| 1000 Points | $8.99 | one-time |
| 2500 Points | $19.99 | one-time |
| 5000 Points | $34.99 | one-time |
| 1000 Points | $59.99 | one-time |


## Frequently asked questions

### Is SoStack free?

SoStack is free to download, with no in-app purchases.

### Is Polymemo free?

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

### Do SoStack or Polymemo have ads?

Neither SoStack nor Polymemo shows ads.

### Which is updated more often, SoStack or Polymemo?

SoStack ships an update every 3 weeks, and Polymemo every 2 days. Most recently, SoStack was updated on October 10, 2026 and Polymemo on October 4, 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.*