# Sentinel vs Tap Alert

The clearest difference is in-app purchases: Sentinel at none against Tap Alert's 1. Sentinel also leads on iOS requirement (15.0 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. Tap Alert sells 1 one-off in-app purchase. Sentinel asks for nothing beyond the download.

## The numbers

| Metric | Sentinel | Tap Alert |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 9.8% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | — |
| Monetization | Free | — |
| Size | 8 MB | 34 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Reference Point Limited](https://appshunter.io/developer/662867085) | [Chris Thompson](https://appshunter.io/developer/1459798812) |

## What reviewers say

### Sentinel

[App page](https://appshunter.io/ios/app/sentinel/id662867082)

Access and verify Network Rail Sentinel smartcards. Check your own card details or authenticate team members and conduct spot checks. Works online for real-time data or offline for card access and stored check history.

**Highlights:** Read Sentinel smartcards via NFC, Scan QR codes for card data, Verify cardholder information, Authenticate team members, Perform spot checks, Check TVPs (Track Vacancy Permits), Offline access to card data

**In-app purchases:** none


### Tap Alert

[App page](https://appshunter.io/ios/app/tap-alert/id6572299815)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock unlimited participants | $1.99 | one-time |


## Frequently asked questions

### Is Sentinel free?

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

### Is Tap Alert free?

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

### Do Sentinel or Tap Alert have ads?

Neither Sentinel nor Tap Alert shows ads.

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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.*