Guides

Trunk vs StockUnison, from one side of the fence

Both keep same-SKU listings in step. Trunk does it across fourteen channels with bundling; StockUnison does it inside Shopify for a third of the price.

Updated 12 September 2026

This comparison is written by one of its subjects, so read it accordingly. What makes it checkable anyway is that nearly every difference is structural — which places each app reaches, what relationship it models between listings, what each is priced on — and you can verify all of it against both public listings in ten minutes. Where a judgement appears, it is labelled.

The short version: these two do the same core job at very different reach. Both keep listings that carry one SKU showing one count, so selling any of them lowers the rest. Trunk does that across roughly fourteen sales channels and adds bundling; StockUnison does it inside Shopify only, and costs $19 against $35. Which one fits is almost entirely decided by whether anything you sell lives outside Shopify.

The job they actually share

Trunk calls it syncing duplicate listings. StockUnison calls it shared stock. It is the same idea: the SKU identifies a physical item, every listing carrying that SKU is a way of selling the same shelf, and they should therefore hold one number between them.

This matters more than the multi-store framing most of this category uses, because the commonest version of the problem has nothing to do with multiple stores — one mug sold on its own and in three bundles, a product duplicated for a campaign, the same jacket under two names. Both apps handle that. Most store-to-store sync tools cannot touch it.

Choose Trunk when

• Anything sells outside Shopify. Amazon, eBay, Etsy, Faire, TikTok, Walmart, Square POS, BigCommerce, Squarespace, Wix, WooCommerce, Bandcamp. This is the whole reason Trunk exists, and StockUnison reaches none of them.
• Bundles and kits must draw down their components. A genuinely hard problem, well solved there, and outside what StockUnison models.
• You want QuickBooks or Xero in the loop.
• A track record is a requirement. 443 reviews, 4.92 average, a 1.1% complaint share — the best record in the category we measured. StockUnison has none. With inventory, refusing to extend trust to a new tool is a defensible position, and this row alone settles it for some people.

Choose StockUnison when

• Every listing is in Shopify — one store or several — and you are paying Trunk for thirteen channels you do not use.
• You want the whole thing previewed first. Nothing is written until you have seen every group it found and the counts each product currently holds, at any catalogue size, on the free plan, for as long as you like.
• You want it to stop rather than guess. If the numbers stop adding up — a CSV import, another app writing stock — the group pauses and asks you to look instead of spreading a count it cannot explain. Ambiguous SKUs are reported and never synced.
• You also need one store feeding others, one way. StockUnison’s other shape is a main store whose counts connected stores copy and can never write back to — a supplier-to-reseller or retail-to-B2B arrangement that a channel tool does not model at all.
• The catalogue is large. StockUnison prices per live store and never by product count; Trunk’s tiers step with volume.

The comparison in one table

Trunk's figures read from its public App Store listing on 28 August 2026; complaint share calculated from the listing's own rating breakdown. Prices as published on the same date. These move — the listing is linked from the Trunk alternatives page so you can check today's.

The honest summary

If you sell on marketplaces, this is not a close comparison and Trunk is your answer — we would say the same thing to a friend. The case for StockUnison is narrow and specific: everything is in Shopify, you want to see exactly what would change before it does, and you would rather not fund reach you never use.