# SD Primer vs Phenyx

The clearest difference is update cadence: Phenyx at daily against SD Primer's every 5 days. Phenyx also leads on iOS requirement (13.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. SD Primer sells 2 in-app purchases, starting at $9.99 per month and Phenyx sells 2 in-app purchases, starting at $7.99 per month. Whichever you choose, the download price is not the number that matters.

SD Primer ships an update every 5 days, Phenyx daily. The most recent releases landed on October 16, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | SD Primer | Phenyx |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/phenyx/id6759697966/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 5 days | **Daily** |
| Monetization | — | Free with in-app purchases |
| Size | 20 MB | 32 MB |
| Requires iOS | 17.0 | **13.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Ernesto Hilvano](https://appshunter.io/developer/1740292069) | [Insp1re LLC](https://appshunter.io/developer/1787057464) |

## What reviewers say

### SD Primer

[App page](https://appshunter.io/ios/app/sd-primer/id6758010557)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| SDPrimer Pro | $9.99 | per month |
| SDPrimer Pro | $99.99 | per year |


### Phenyx

[App page](https://appshunter.io/ios/app/phenyx/id6759697966)

This reading companion helps you capture thoughts, connect ideas across books with AI, and engage in deeper understanding through Socratic questioning. It offers personalized reading modes and a community feature for sharing insights.

**Highlights:** AI-powered idea connection, Socratic questioning for deeper understanding, Personalized reading modes, Knowledge graph visualization, Community sharing and book clubs, Spaced repetition for insights, Progress tracking with streaks and badges

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Phenyx Unlimited Monthly | $7.99 | per month |
| Phenyx Unlimited Annual | $74.99 | per year |


## Frequently asked questions

### Is SD Primer free?

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

### Is Phenyx free?

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

### Do SD Primer or Phenyx have ads?

Neither SD Primer nor Phenyx shows ads.

### Which is updated more often, SD Primer or Phenyx?

SD Primer ships an update every 5 days, and Phenyx daily. Most recently, SD Primer was updated on October 16, 2026 and Phenyx 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.*