# Codebook vs Linear System Solver

The clearest difference is price: Codebook at Free against Linear System Solver's $0.99. Linear System Solver's advantage is in-app purchases (none vs 21) and ads (none vs shown). On update cadence, device support and iOS requirement there is nothing between them.

Codebook is free to download; Linear System Solver costs $0.99 up front. Codebook sells 20 in-app purchases, starting at $2.99 per 7 days. Linear System Solver asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 3 days. The most recent releases landed on September 27, 2026 and September 26, 2026 respectively.

## The numbers

| Metric | Codebook | Linear System Solver |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | **[5.0 (31 ratings)](https://appshunter.io/ios/app/codebook-ai-coding-companion/id6467008280/reviews)** | — |
| Number of ratings | **31** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 3 days | Every 3 days |
| Monetization | Free with in-app purchases | — |
| Size | 136 MB | 1 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Noah Clark](https://appshunter.io/developer/1708029582) | [Luigi Fonti](https://appshunter.io/developer/360904185) |

## What reviewers say

### Codebook

[App page](https://appshunter.io/ios/app/codebook-ai-coding-companion/id6467008280)

This app offers AI-powered coding assistance, lessons, and a built-in code editor. It helps users learn, write, run, and test code, build portfolios, and earn certifications. Access to advanced AI models is provided.

**Highlights:** AI-powered coding assistance, Instructor-led coding lessons, Built-in code editor, Code execution and testing, Certification and rewards, Personalized learning plans, Developer portfolio builder

**Features:** macOS Compatibility

**In-app purchases (20)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Codebook Remove Ads | $2.99 | per 7 days |
| Codebook Professional | $4.99 | per 7 days |
| Codebook Pro Without Ads | $7.99 | per 7 days |
| Codebook Challenge Answer | $1.99 | one-time |
| Codebook Widgets 1 Month | $2.99 | one-time |
| Codebook Challenge Refresh | $2.99 | one-time |
| 25 Codebook Tokens | $2.99 | one-time |
| GPT 4 Access | $2.99 | one-time |
| 50 Codebook Tokens | $3.99 | one-time |
| Codebook Certification | $3.99 | one-time |
| Codebook Tokens | $5.99 | one-time |
| 50 Codebook Tokens | $5.99 | one-time |
| GPT4-Codebook | $5.99 | one-time |
| Codebook Remove Ads | $5.99 | one-time |
| 100 Codebook Tokens | $8.99 | one-time |
| Codebook Remove Ads | $9.99 | one-time |
| GPT-4 Access for Codebook | $9.99 | one-time |
| GPT-4 1 Month Access | $12.99 | one-time |
| Codebook Remove Ads | $12.99 | one-time |
| 1 Month Idea Hub Access | $14.99 | one-time |


### Linear System Solver

[App page](https://appshunter.io/ios/app/linear-system-solver/id6469396751)

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

**In-app purchases:** none


## Frequently asked questions

### Is Codebook free?

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

### Is Linear System Solver free?

Linear System Solver costs $0.99, with no in-app purchases.

### Do Codebook or Linear System Solver have ads?

Codebook shows ads; Linear System Solver does not.

### Which is updated more often, Codebook or Linear System Solver?

Codebook ships an update every 3 days, and Linear System Solver every 3 days. Most recently, Codebook was updated on September 27, 2026 and Linear System Solver on September 26, 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.*