# SmartBook Service vs iSign

The clearest difference is in-app purchases: SmartBook Service at none against iSign's 12. SmartBook Service also leads on ads (none vs shown) and device support (3 vs 1). On price and update cadence there is nothing between them.

Both are free to download. iSign sells 12 in-app purchases, starting at $4.99 per 7 days. SmartBook Service asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on October 26, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | SmartBook Service | iSign |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.4 (49 ratings)](https://appshunter.io/ios/app/isign-sign-documents/id6748340697/reviews)** |
| Number of ratings | — | **49** |
| Positive reviews | — | 81.8% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 3 weeks | Every 3 weeks |
| Monetization | — | Free with in-app purchases |
| Size | 11 MB | 27 MB |
| Requires iOS | **12.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | +4 |
| Developer | [ONM Systems Ltd.](https://appshunter.io/developer/953087849) | [PRODEKS](https://appshunter.io/developer/1711040618) |

## What reviewers say

### SmartBook Service

[App page](https://appshunter.io/ios/app/smartbook-service/id1464190552)

**Features:** macOS Compatibility

**In-app purchases:** none


### iSign

[App page](https://appshunter.io/ios/app/isign-sign-documents/id6748340697)

Effortlessly sign and manage your digital documents with an AI-powered signature generator. This tool allows you to create custom electronic signatures, sign PDFs, fill forms, and add annotations directly from your device for a streamlined workflow.

**Highlights:** AI-generated electronic signatures, Sign and export PDF files, Capture and digitize handwritten signatures, Fill interactive PDF forms, Add custom stamps and annotations, Cross-device accessibility

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

**In-app purchases (12)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium features (Weekly) | $4.99 | per 7 days |
| Premium features (Weekly) | $6.99 | per 7 days |
| Premium features (Weekly) | $6.99 | per 7 days |
| Premium features (Month) | $9.99 | per month |
| Premium features (Month) | $14.99 | per month |
| Premium features (Month) | $14.99 | per month |
| Premium features (Month) | $19.99 | per month |
| Premium features (Annual) | $49.99 | per year |
| Premium Year Access | $69.99 | per year |
| Premium Year Access | $69.99 | per year |
| Lifetime Access | Free | one-time |
| Lifetime Access | $119.99 | one-time |


## Frequently asked questions

### Is SmartBook Service free?

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

### Is iSign free?

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

### Do SmartBook Service or iSign have ads?

iSign shows ads; SmartBook Service does not.

### Which is updated more often, SmartBook Service or iSign?

SmartBook Service ships an update every 3 weeks, and iSign every 3 weeks. Most recently, SmartBook Service was updated on October 26, 2026 and iSign on October 28, 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.*