---
title: "CheckoutOS vs Fast Bundle: bundles and upsells compared"
description: "Compare Fast Bundle and CheckoutOS: mix-and-match bundles, cart upsells and pricing by bundle sales, checked October 16, 2026."
url: "https://chargezen.com/compare/fast-bundle"
updated: "2026-10-16"
---

Canonical URL: https://chargezen.com/compare/fast-bundle

# Flexible bundles, plus checkout offers.

Fast Bundle is a top-rated app for mix-and-match and build-your-own bundles. CheckoutOS covers bundles with cart transforms and adds checkout, post-purchase and thank-you page offers, rewards and checkout chat. $99/month. No sales-based tiers.

Self-serve software or help with setup and migration.

## Side by side

See exactly what you get with each one.

**Who each one is best for.** Choose Fast Bundle if you need very flexible mix-and-match or build-your-own bundles, including in Shopify POS. Choose CheckoutOS if you want checkout offers, post-purchase upsells, bundles, checkout blocks and cart rules from one app for $99 a month, with no per-order fees.

**Checked October 16, 2026.** Fast Bundle facts come from [the Fast Bundle App Store listing](https://apps.shopify.com/fast-bundle-product-bundles). “Not listed” means those pages didn’t name the feature when we checked, not that Fast Bundle can’t do it.

| Feature | Fast Bundle | Chargezen |
| --- | --- | --- |
| Bundles Mix-and-match, fixed, BOGO and build-your-own | Included | Included |
| Cart upsells Offers in the cart drawer | Included | Included |
| A/B testing Test different offers | Included | Included |
| Offer a subscription Subscription upgrades | With Appstle and Seal | With Chargezen Subscriptions |
| Post-purchase upsells One-click offers after checkout | Not listed | Included |
| Thank you page offers Offers on the confirmation page | Not listed | Included |
| Rewards at checkout Show points as customers buy | Not listed | Included |
| Pricing by bundle sales Price rises with bundle sales | Included | No, $99/month |

## What you’d really pay

Fast Bundle prices by monthly bundle sales. CheckoutOS is one monthly price.

### Fast Bundle

Up to $1,000/mo bundle sales

$19/mo

Up to $3,000/mo

$49/mo

Up to $10,000/mo

$139/mo

Auto Bundle Detection

+$49/mo

Estimated Annual Cost

Depends on bundle sales

Yearly plans are $180, $468 and $1,380. Free on development stores. [Fast Bundle App Store listing](https://apps.shopify.com/fast-bundle-product-bundles), checked October 16, 2026.

### Chargezen

CheckoutOS

$99/mo

Per-order fee

$0

Share of upsell revenue

$0

Sales-based tiers

None

Annual Cost

$1,188/year

CheckoutOS is $99/month, billed monthly, with no per-order fees. Pre-orders are included. Taxes are extra. [Chargezen pricing](https://chargezen.com/pricing).

## Plan your move from Fast Bundle

Check your data, billing dates and launch plan before you switch.

[Talk through your move](https://chargezen.com/contact-sales)

*   [See CheckoutOS](https://chargezen.com/checkoutos)

1.  01
    
    ### List your offers
    
    Write down the Fast Bundle offers, bundles and rules that perform best today.
    
2.  02
    
    ### Rebuild them in CheckoutOS
    
    Create the same offers in the cart, checkout, post-purchase and thank-you page.
    
3.  03
    
    ### Test side by side
    
    Use A/B tests to compare results before you switch everything over.
    
4.  04
    
    ### Turn off Fast Bundle
    
    Remove the old offers so customers only see one set.
    

## Why brands switch to Chargezen

### Unified Platform

Run AI agents, texts and email, upsells, creators and subscriptions from one place.

### AI-Powered

AI agents answer customers, follow up and handle everyday busywork for your team.

### Clear Pricing

See prices and usage costs, billed monthly or yearly.

## Ready to switch from Fast Bundle?

See the products, prices and setup help that fit your brand.

[Get started](https://admin.chargezen.com/signup)

## Common questions

### How much does Fast Bundle cost compared with CheckoutOS?

Fast Bundle is $19/month up to $1,000 in monthly bundle sales, $49 up to $3,000 and $139 up to $10,000, with Auto Bundle Detection at $49/month more (checked October 16, 2026). CheckoutOS is $99/month at any volume.