# Run Custom JS on Background vs NasScale

The clearest difference is update cadence: NasScale at every 8 days against Run Custom JS on Background's every 4 months. 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.

Run Custom JS on Background ships an update every 4 months, NasScale every 8 days. The most recent releases landed on October 16, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Run Custom JS on Background | NasScale |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 8 days** |
| Size | 1 MB | 68 MB |
| Requires iOS | 17.6 | **17.0** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Takada Hiroki](https://appshunter.io/developer/1847165450) | [贺 黄](https://appshunter.io/developer/6796553051) |

## What reviewers say

### Run Custom JS on Background

[App page](https://appshunter.io/ios/app/run-custom-js-on-background/id6755627440)

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

**In-app purchases:** none


### NasScale

[App page](https://appshunter.io/ios/app/nasscale/id6796591787)

**In-app purchases:** none


## Frequently asked questions

### Is Run Custom JS on Background free?

Run Custom JS on Background is free to download, with no in-app purchases.

### Is NasScale free?

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

### Do Run Custom JS on Background or NasScale have ads?

Neither Run Custom JS on Background nor NasScale shows ads.

### Which is updated more often, Run Custom JS on Background or NasScale?

Run Custom JS on Background ships an update every 4 months, and NasScale every 8 days. Most recently, Run Custom JS on Background was updated on October 16, 2026 and NasScale on October 10, 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.*