# Upstream vs Inbox Zero

The clearest difference is in-app purchases: Upstream at none against Inbox Zero's 2. Upstream also leads on iOS requirement (15.1 vs 18.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Inbox Zero sells 2 in-app purchases, starting at $19.99 per month. Upstream asks for nothing beyond the download.

Upstream ships an update every 2 weeks, Inbox Zero weekly. The most recent releases landed on October 24, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Upstream | Inbox Zero |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.7 (3 ratings)](https://appshunter.io/ios/app/upstream-email/id6751403722/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Weekly** |
| Monetization | **Free** | Subscription |
| Size | 87 MB | 35 MB |
| Requires iOS | **15.1** | 18.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Upstream Labs](https://appshunter.io/developer/1834893204) | [Inbox Zero Inc.](https://appshunter.io/developer/1880462164) |

## What reviewers say

### Upstream

[App page](https://appshunter.io/ios/app/upstream-email/id6751403722)

This AI-powered inbox automatically organizes emails, drafts replies in your unique writing style, and sends follow-ups. It learns your workflow to minimize distractions and ensure no important messages are missed.

**Highlights:** AI email triaging, Personalized draft writing, Automated follow-ups, Self-organizing inbox, Learns user workflow

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

**In-app purchases:** none


### Inbox Zero

[App page](https://appshunter.io/ios/app/inbox-zero-ai-email-assistant/id6759736561)

This AI-powered assistant helps you manage your email inbox efficiently. It prioritizes important messages, drafts replies in your style, and helps you unsubscribe from unwanted newsletters. Automate email handling with custom rules and stay in control of your communications.

**Highlights:** Prioritize important emails, Draft AI-assisted replies, Unsubscribe from newsletters, Bulk archive emails, Create custom automation rules, Manage multiple Gmail accounts

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Inbox Zero Starter Monthly | $19.99 | per month |
| Inbox Zero Starter Annual | $199.99 | per year |


## Frequently asked questions

### Is Upstream free?

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

### Is Inbox Zero free?

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

### Do Upstream or Inbox Zero have ads?

Neither Upstream nor Inbox Zero shows ads.

### Which is updated more often, Upstream or Inbox Zero?

Upstream ships an update every 2 weeks, and Inbox Zero weekly. Most recently, Upstream was updated on October 24, 2026 and Inbox Zero on October 31, 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.*