BoxGuard: PO Box Blocker vs King Checkout Validation
Two Shopify apps, side by side: detected stores, momentum, reviews, plans, listed features and who runs each. Store counts as of Nov 3, 2026.
The short answer
- Both list a free plan. Paid plans start at $9.99/month for BoxGuard and $4.99/month for King Checkout Validation.
- King Checkout Validation lists 12 features BoxGuard’s listing doesn’t mention, including Cart-based, Collection-specific, Custom messages.
Head to head
- Australia
Momentum
New reviews each month
Review pace is the clearest public read on how fast an app is winning new merchants.
Free Plan
Pro Plan
Free
- · Create and test validation rules
- · Free for development stores
Basic
- · Block PO box addresses
- · Live chat and email support
- · Require VAT numbers
- · Require house, apartment or suite number
Premium
- · All Basic features
- · Build regular expression rules
- · Combine cart and customer conditions
- · Detect non-Latin characters
- · Match keywords in checkout fields
- · Set checkout field length limits
Coverage counts what each App Store listing names. Every feature, checked off app by app, is in Shoplist.
See every featureCarriers like FedEx and UPS cannot deliver to PO Boxes, causing returned packages, reshipment expenses, and address correction penalties. BoxGuard validates shipping addresses directly within Shopify Checkout before payment is processed. You can restrict PO Boxes, military APO/FPO addresses, parcel lockers, and custom keywords, while setting custom error prompts.
Use checkout validation to check shipping and billing address fields before orders are placed. Block PO boxes, require house or apartment numbers, and check postcode/ZIP, email and VAT/tax ID formats. Match phone country codes to address countries. Set order limits by cart amount, quantity or weight, with conditions for products, customer tags and countries. Use keyword, regex and field-length checks.
- Block PO Boxes and parcel lockers in real time at checkout.
- Restrict military APO/FPO destinations and custom address keywords.
- Customize error messages to prompt buyers for a valid street address.
- Exempt trusted customer tags or apply rules to specific product tags.
- Verifies presence of house/apartment number in addresses
- Validates completion of customer's VAT number (Tax exemption)
- Filters out Post Office (PO) Box addresses
- Field Length Validation, Custom Keyword and Regular Expression Validation
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 |  King Checkout Validation | |
|---|---|---|
| Detected stores | Not published | 1 |
| 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 | Home & Garden |
| Top store countries | Not published | Australia |
Reviews
| Measure | King Checkout Validation | |
|---|---|---|
| App Store rating | Not published | 5.0 ★ |
| App Store reviews | Not published | 24 |
| New reviews, 28 days | Not enough data | 0 |
| Reviewers a year or more in | Not enough data | Not enough data |
Pricing
| Measure | King Checkout Validation | |
|---|---|---|
| Free plan | Yes | Yes |
| Lowest paid monthly plan | $9.99/month | $4.99/month(ahead) |
| Longest free trial | 7 days | 7 days |
| Plans listed | 2 | 3 |
Listing
| Measure | King Checkout Validation | |
|---|---|---|
| Shopify category rank | Not enough data | #24 |
| Shopify App Charts | Not on this week’s charts | #24 in Checkout - Other |
| Built for Shopify | No | Yes |
| Launched | Oct 31, 2026 | Mar 15, 2024 |
| Languages | 1 | 1 |
| Developer | Mad Syntax | Lightcone |
FAQ
BoxGuard and King Checkout Validation: common questions
- Is BoxGuard or King Checkout Validation cheaper?
- Both list a free plan. Paid plans start at $9.99/month for BoxGuard and $4.99/month for King Checkout Validation. Shoplist compares base prices only between monthly plans in the same currency; usage charges and annual plans vary, so check each plan’s limits.
- What features does each app list that the other doesn’t?
- BoxGuard lists 1 the others don’t mention, such as Cart alerts. King Checkout Validation lists 12 the others don’t mention, such as Cart-based, Collection-specific, Custom messages, Customer tags. A feature missing from a listing may still be supported; this compares what each App Store listing says.
- 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 Nov 3, 2026; 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 Nov 3, 2026. 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.