# Rattlegram vs icMercury

The clearest difference is update cadence: icMercury at every 5 days against Rattlegram's every 9 months. icMercury also leads on iOS requirement (15.1 vs 17.6). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Rattlegram ships an update every 9 months, icMercury every 5 days. The most recent releases landed on September 8, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Rattlegram | icMercury |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (23 ratings)](https://appshunter.io/ios/app/rattlegram/id1664526096/reviews)** | — |
| Number of ratings | **23** | — |
| Positive reviews | 90.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 9 months | **Every 5 days** |
| Monetization | Free | — |
| Size | 1 MB | 67 MB |
| Requires iOS | 17.6 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [aicodix GmbH](https://appshunter.io/developer/1664526098) | [Interstellar Communication Holdings, Inc.](https://appshunter.io/developer/1800208923) |

## What reviewers say

### Rattlegram

[App page](https://appshunter.io/ios/app/rattlegram/id1664526096)

This app utilizes advanced COFDM technology for audio-based SMS transmission. It supports various modes with specific encoding and modulation techniques, requiring minimal bandwidth for efficient data transfer.

**Highlights:** COFDM technology, Audio-based SMS, 160 ms OFDM symbols, Differential PSK modulation, Forward error correction, Low bandwidth requirement

**In-app purchases:** none


### icMercury

[App page](https://appshunter.io/ios/app/icmercury/id6742833529)

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

**In-app purchases:** none


## Frequently asked questions

### Is Rattlegram free?

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

### Is icMercury free?

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

### Do Rattlegram or icMercury have ads?

Neither Rattlegram nor icMercury shows ads.

### Which is updated more often, Rattlegram or icMercury?

Rattlegram ships an update every 9 months, and icMercury every 5 days. Most recently, Rattlegram was updated on September 8, 2026 and icMercury on September 19, 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.*