modlet: Block PO Box & Lockers vs PO Box Blocker — AddressFence
Two Shopify apps, side by side: detected stores, momentum, reviews, plans, listed features and who runs each. Store counts as of Oct 31, 2026 for modlet, Oct 13, 2026 for PO Box Blocker.
The short answer
- Both list a free plan. Paid plans start at $7.99/month for modlet and $9.99/month for PO Box Blocker.
Head to head
Momentum
New reviews each month
Review pace is the clearest public read on how fast an app is winning new merchants.
Free
- · Address Simulator & Testing Tool
- · Block PO Boxes globally (Instant setup)
- · Native & Secure Checkout Validation
- · Up to 250 Store Orders per Month
Pro
- · Country & Region Whitelisting
- · Custom Error Messages & Translations
- · Granular Pattern Rules
- · Product Exemptions
- · Shipping Method Filtering
- · Unlimited Orders & Address Validations
Enterprise
- · 1-on-1 Workflow & Strategy Configuration
- · Dedicated Technical Account Manager
- · Guaranteed Custom SLA & Compliance Help
- · On-Demand Custom Data Exports & Reports
- · Priority Custom Feature Development
- · White-Glove Setup & Dedicated Onboarding
Free
- · Shipping PO Box/locker + 10 ZIP rules
Pro
- · Free+: street #, messages, regions, CSV
Plus
- · Beyond Pro: billing rules + allowlists
Coverage counts what each App Store listing names. Every feature, checked off app by app, is in Shoplist.
See every featureProtect your shipping margins with reliable, global PO Box blocking. Built natively into Shopify Checkout, it physically blocks checkout completion for restricted addresses—ensuring 100% reliability. Why offer a generous free tier? Built by a veteran cloud architect, our highly efficient infrastructure keeps costs low, and we love helping new stores get off the ground.
AddressFence stops PO box and parcel locker addresses from being used as the shipping address at checkout. Install, turn on the PO box and locker rules, and they work right away; a small set of ZIP/postal rules is included free. When you need more, paid upgrades add street-number checks, custom checkout error messages, region rules, CSV import, billing-address rules and allowlists.
- Block PO Boxes, Lockers, and Military Addresses to prevent failed deliveries.
- Stop expensive UPS/FedEx carrier return fees instantly.
- Native Shopify Checkout integration—unhackable with zero theme code.
- Exempt specific countries or shipping methods from blocking rules.
- Publish checkout-native address rules without theme code.
- Block PO Boxes, lockers, ZIP/postal ranges, and unsupported regions.
- Preview, publish, roll back, and restore validation configs.
All the numbers
Every figure, side by side
A green dot marks the app ahead on a measured figure. Estimates, gaps and apps that leave no storefront trace never take the lead.
Adoption
| Measure |  modlet |  PO Box Blocker |
|---|---|---|
| Detected stores | Not published | Not published |
| Net store change, 28 days | 0 | 0 |
| Stores added, 28 days | Not enough data | Not enough data |
| Big-brand share | Not enough data | Not enough data |
| Top store categories | Not published | Not published |
| Top store countries | Not published | Not published |
Reviews
| Measure | modlet | PO Box Blocker |
|---|---|---|
| App Store rating | 5.0 ★ | Not published |
| App Store reviews | 2 | Not published |
| New reviews, 28 days | Not enough data | Not enough data |
| Reviewers a year or more in | Not enough data | Not enough data |
Pricing
| Measure | modlet | PO Box Blocker |
|---|---|---|
| Free plan | Yes | Yes |
| Lowest paid monthly plan | $7.99/month(ahead) | $9.99/month |
| Longest free trial | 30 days | Not listed |
| Plans listed | 3 | 3 |
Listing
| Measure | modlet | PO Box Blocker |
|---|---|---|
| Shopify category rank | #67(ahead) | #149 |
| Shopify App Charts | Not on this week’s charts | Not on this week’s charts |
| Built for Shopify | No | No |
| Launched | Mar 9, 2026 | Jun 22, 2026 |
| Languages | 1 | 1 |
| Developer | modlet | momiji-shop |
FAQ
modlet and PO Box Blocker: common questions
- Is modlet or PO Box Blocker cheaper?
- Both list a free plan. Paid plans start at $7.99/month for modlet and $9.99/month for PO Box Blocker. Shoplist compares base prices only between monthly plans in the same currency; usage charges and annual plans vary, so check each plan’s limits.
- Where does this comparison’s data come from?
- Shoplist crawls Shopify storefronts to detect which apps each store runs, and reads each app’s Shopify App Store listing for reviews, pricing, features and integrations. Store counts are as of Oct 31, 2026 for modlet, Oct 13, 2026 for PO Box Blocker; estimated figures are labeled.
How Shoplist compares apps
Store counts come from Shoplist’s crawl of Shopify storefronts, which detects the apps each store runs; they are as of Oct 31, 2026 for modlet, Oct 13, 2026 for PO Box Blocker. Reviews, ratings, plans, features and integrations come from each app’s Shopify App Store listing. 28-day figures are labeled when estimated, and a figure that is missing or estimated never decides who leads. Read the methodology.