# Principle vs Backtest Trading

The clearest difference is ads: Backtest Trading at none against Principle's shown. Backtest Trading also leads on update cadence (every 3 days vs every 10 days) and device support (4 vs 2). Principle's advantage is iOS requirement (13.0 vs 17). On price and in-app purchases there is nothing between them.

Both are free to download. Principle sells 4 one-off in-app purchases and Backtest Trading sells 4 in-app purchases, starting at $9.99 per month. Whichever you choose, the download price is not the number that matters.

Principle ships an update every 10 days, Backtest Trading every 3 days. The most recent releases landed on October 14, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | Principle | Backtest Trading |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 10 days | **Every 3 days** |
| Size | 49 MB | 30 MB |
| Requires iOS | **13.0** | 17 |
| Devices | iPhone, iPod | **iPhone, iPad, Mac, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [주식회사 유자](https://appshunter.io/developer/1851710513) | [Dat Thanh Nguyen](https://appshunter.io/developer/1481241176) |

## What reviewers say

### Principle

[App page](https://appshunter.io/ios/app/principle-stock-backtest-sim/id6776831023)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 10 Tokens | $1.99 | one-time |
| 33 Tokens | $4.99 | one-time |
| 115 Tokens | $14.99 | one-time |
| 600 Tokens | $59.99 | one-time |


### Backtest Trading

[App page](https://appshunter.io/ios/app/backtest-trading/id6783314365)

**Features:** Apple Watch app, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| StopTrading Pro | $9.99 | per month |
| StopTrading Power | $29.99 | per month |
| StopTrading Pro Annual | $79.99 | per year |
| StopTrading Power Annual | $239.99 | per year |


## Frequently asked questions

### Is Principle free?

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

### Is Backtest Trading free?

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

### Do Principle or Backtest Trading have ads?

Principle shows ads; Backtest Trading does not.

### Which is updated more often, Principle or Backtest Trading?

Principle ships an update every 10 days, and Backtest Trading every 3 days. Most recently, Principle was updated on October 14, 2026 and Backtest Trading on October 17, 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.*