Looking for a More Reliable NASP Connected Inventory Alternative?

Tired of synchronization lag, overselling surprises, and unhelpful support? Switch to Duplicup — the 5.0-star rated Shopify app built for instantaneous, bulletproof shared inventory across duplicate listings.

Install Duplicup on Shopify App Store

Duplicup vs. NASP Connected Inventory Comparison

CapabilityDuplicup ‑ Duplicate SKU SyncNASP Connected Inventory
App Store Rating5.0 / 5.0 Stars (Verified)3.3 / 5.0 Stars (Many Complaints)
Real-Time Sync SpeedSub-second via Webhooks + GraphQLReported delays & sync lag
Manual Variant LinkingYes — Custom Link GroupsLimited / Identical SKUs only
Multi-Location & POSNative per-location isolated syncComplex setup
Free Plan AvailableYes (Up to 3 SKUs free)Paid-only tiers
Customer SupportDirect Engineer Priority SupportSlow response times reported

3 Reasons Shopify Merchants Make the Switch

  • No More Sync Delays: Duplicup synchronizes stock in milliseconds using Shopify webhooks and distributed locking, eliminating the race conditions that cause overselling during flash sales.
  • Manual Variant Linking: Link any variants together into a shared inventory pool even if their SKU codes differ.
  • Direct Developer Support: Work directly with the engineers building the app for rapid setup and custom feature requests.

Verified Merchant Review

“I've tried several other apps for managing shared inventory across variants and locations, and none of them quite delivered. This one finally does. Everything stays perfectly in sync.”

— Stash Shop (United Kingdom, 5/5 Stars)

Frequently Asked Questions

Why are merchants switching from NASP Connected Inventory to Duplicup?
Merchants switch due to reliability and support concerns. Duplicup provides sub-second webhook synchronization with distributed locking and direct engineer support.
How long does migration take?
Less than 5 minutes. No theme modifications or liquid code to remove.
Can I link variants with different SKUs?
Yes, via Duplicup Custom Link Groups.