FlexiFees ‑ Conditional Fees vs UpsellPlus Checkout Upsellfor Shopify (2026)
FlexiFees ‑ Conditional Fees and UpsellPlus Checkout Upsell are both Shopify apps operating within the 'Checkout - Other' category, but they address very different merchant needs. FlexiFees focuses on adding mandatory fees and surcharges to the cart based on product or cart conditions. It aims to give merchants greater control over pricing by automatically adding fees via webhook when cart contents change. UpsellPlus, on the other hand, is designed to increase average order value (AOV) through checkout upsells, post-purchase offers, and thank you page customization. The stark difference in user ratings and review counts highlights a significant performance gap. UpsellPlus enjoys a perfect 5/5 rating from over 100 reviews, suggesting high user satisfaction and reliability. In contrast, FlexiFees suffers from a very low 2.8/5 rating based on only 2 reviews, indicating potential issues with functionality, user experience, or customer support. UpsellPlus also offers exclusive checkout upsell features only available to Shopify Plus merchants. The integration of reviews, banners, and custom payment/delivery options further differentiate UpsellPlus, focusing on enhancing the overall customer journey and purchase experience.
At a Glance
FlexiFees ‑ Conditional Fees
2 reviews
UpsellPlus Checkout Upsell
103 reviews
Detailed Overview
FlexiFees ‑ Conditional Fees
Add extra mandatory fees & surcharges to your cart. Charge additional product fees or cart based
Key Features
- Product extra fees
- Cart fees (option to be taxable or not; optional fee custom SKU)
- Automatically add or remove fee when cart object is changed
UpsellPlus Checkout Upsell
Boost your AOV with checkout upsells, product & post purchase offers & thank you page editing
Key Features
- Modify checkout page with upsells, shipping bar & more (Shopify Plus Exclusive)
- Customize thank you page with reviews, upselling and cross-selling, & more
- Create post purchase one-click upsell & downsell offers (single & multi-product)
- Add checkout extensions to show reviews, banners, custom payment and delivery
- Upsell on the product page, cart page, cart drawer, checkout and post-purchase!
Feature Comparison
| Rating | 2.8/5 | 5/5 |
Rating FlexiFees ‑ Conditional Fees2.8/5 UpsellPlus Checkout Upsell5/5 | ||
| Reviews | 2 | 103 |
Reviews FlexiFees ‑ Conditional Fees2 UpsellPlus Checkout Upsell103 | ||
| Primary Function | Add conditional fees & surcharges to cart | Increase AOV through upsells & post-purchase offers |
Primary Function FlexiFees ‑ Conditional FeesAdd conditional fees & surcharges to cart UpsellPlus Checkout UpsellIncrease AOV through upsells & post-purchase offers | ||
| Checkout Modification | Adds fees via webhook | Modifies checkout page with upsells and extensions (Shopify Plus exclusive) |
Checkout Modification FlexiFees ‑ Conditional FeesAdds fees via webhook UpsellPlus Checkout UpsellModifies checkout page with upsells and extensions (Shopify Plus exclusive) | ||
| Target Merchant | Merchants needing to add specific fees based on conditions | Merchants focused on increasing AOV through upsells |
Target Merchant FlexiFees ‑ Conditional FeesMerchants needing to add specific fees based on conditions UpsellPlus Checkout UpsellMerchants focused on increasing AOV through upsells | ||
| Ease of Use | Potentially complex setup with webhook integration | No developer required |
Ease of Use FlexiFees ‑ Conditional FeesPotentially complex setup with webhook integration UpsellPlus Checkout UpsellNo developer required | ||
| Value Proposition | Flexibility in adding mandatory fees | Increased revenue through strategic upsells |
Value Proposition FlexiFees ‑ Conditional FeesFlexibility in adding mandatory fees UpsellPlus Checkout UpsellIncreased revenue through strategic upsells | ||
| Post-Purchase Offer | No post purchase offer | Create post purchase one-click upsell & downsell offers |
Post-Purchase Offer FlexiFees ‑ Conditional FeesNo post purchase offer UpsellPlus Checkout UpsellCreate post purchase one-click upsell & downsell offers | ||
- Conversion Audit
- Speed Audit
- SEO Audit
Conversion Audit
Our Verdict
UpsellPlus is clearly the stronger choice for merchants seeking to boost their average order value and enhance the customer checkout experience through upsells and post-purchase offers. Its significantly higher rating and large number of positive reviews suggest a reliable and effective solution.
FlexiFees might be considered by merchants who absolutely require the ability to add complex conditional fees and are comfortable troubleshooting potential issues, given its low rating and limited reviews. However, the lack of user validation and the potential complexity of webhook integration make it a riskier option compared to the well-regarded and feature-rich UpsellPlus. For most merchants, UpsellPlus offers a more straightforward and proven path to increasing revenue through strategic checkout optimization.
Common Questions
Which app is easier to set up and use?
UpsellPlus explicitly states that no developer is required, implying a simpler setup process. FlexiFees, using webhooks, might be more complex, especially for non-technical users.
Which app is better for increasing revenue?
UpsellPlus is specifically designed to increase revenue through upsells and post-purchase offers. FlexiFees focuses on adding fees, which might increase overall charges to the customer but not necessarily revenue.
Which app modifies the checkout page?
UpsellPlus directly modifies the checkout page with upsells and other extensions. FlexiFees works in the background via webhook and updates the cart object.
Which app has better customer reviews?
UpsellPlus has significantly better customer reviews, with a perfect 5/5 rating and over 100 reviews. FlexiFees has a low 2.8/5 rating based on only 2 reviews.
Which app is suitable for Shopify Plus merchants?
UpsellPlus offers exclusive checkout modification features for Shopify Plus merchants, providing additional value for those on the Plus plan. FlexiFees makes no such distinction.
Get More From Your Shopify Store
Run audits for SEO, CRO, PageSpeed, and AI visibility. Get a clear report and actionable fixes.
Try Fix My Store