# Invoice.app vs seashellOS

The clearest difference is update cadence: seashellOS at daily against Invoice.app's weekly. Invoice.app's advantage is iOS requirement (18.6 vs 26.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Invoice.app sells 5 in-app purchases, starting at $1.99 per month and seashellOS sells 6 in-app purchases, starting at $9.00 per month. Whichever you choose, the download price is not the number that matters.

Invoice.app ships an update weekly, seashellOS daily. The most recent releases landed on October 20, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | Invoice.app | seashellOS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (19 ratings)](https://appshunter.io/ios/app/invoiceapp-invoice-maker/id1370893360/reviews)** | — |
| Number of ratings | **19** | — |
| Positive reviews | 70.4% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Weekly | **Daily** |
| Monetization | Free with in-app purchases | — |
| Size | 61 MB | 61 MB |
| Requires iOS | **18.6** | 26.0 |
| Devices | **iPhone, iPad, Mac** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Stojanowski Consulting Ltd](https://appshunter.io/developer/939009353) | [Seashell Studios LLC](https://appshunter.io/developer/1881349061) |

## What reviewers say

### Invoice.app

[App page](https://appshunter.io/ios/app/invoiceapp-invoice-maker/id1370893360)

Generate invoices, estimates, and other financial documents with this easy-to-use tool. Manage clients, track payments, and customize templates for your business needs. Sync data across devices and work offline.

**Highlights:** Create invoices, estimates, and purchase orders, Track and export expenses, Customize PDF templates, Manage clients and document items, Keep track of payments, Work offline and sync across devices, Offer discounts and convert estimates to invoices

**Features:** Vision Pro support

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Starter | $1.99 | per month |
| Premium | $4.49 | per month |
| Starter | $19.99 | per year |
| Premium | $34.99 | per year |
| Premium | $99.99 | one-time |


### seashellOS

[App page](https://appshunter.io/ios/app/seashellos/id6759867574)

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Tier - 1 Month | $9.00 | per month |
| Pro+ Tier | $19.99 | per month |
| Pro Tier - Annual | $85.99 | per year |
| Team Plan - Monthly | $99.00 | per month |
| Pro Plus - Annual | $180.99 | per year |
| Team Plan - Annual | $949.00 | per year |


## Frequently asked questions

### Is Invoice.app free?

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

### Is seashellOS free?

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

### Do Invoice.app or seashellOS have ads?

Neither Invoice.app nor seashellOS shows ads.

### Which is updated more often, Invoice.app or seashellOS?

Invoice.app ships an update weekly, and seashellOS daily. Most recently, Invoice.app was updated on October 20, 2026 and seashellOS on October 6, 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.*