プラスシッピング | ヤマト・日本郵便・佐川を特別料金で配送

Should you install it?

If you are a small Japanese store still handwriting waybills or juggling CSVs, this does the core job well: buy and bulk-print ヤマト運輸 and 日本郵便 waybills inside the Shopify admin, send tracking emails in bulk, and pay flat nationwide rates that several reviewers say beat what they could negotiate alone — one puts their postage at about 60% of what it was. The workflow praise is consistent and recent, and mistake recovery exists (cancel a wrongly-bought label within 10 days). The serious caveat is timing: every sub-3-star review in this app's four-year history arrived after December 2025, and they are about support and billing, not features — two merchants got no reply to enquiries, with the developer twice admitting its own system was not receiving their emails and telling them to use a ticket form instead; one was charged above the normal contract rate on the GOLD plan, another had a tier upgrade delayed a month. Do not install if you ship multi-parcel (複数個口) orders, if you push much past ten parcels a day, or if your customers' names and addresses often use rare or old-form characters, since the carrier API only accepts ShiftJIS-range characters. Budget 3–7 business days from application to your first label, expect the fulfilled status to fire when you buy the label, and use the web ticket form rather than email for anything that matters — including anything about your plan tier or invoice, which is where recent merchants have lost the most time.

Fair evidence. Thirty reviews, 27 with text, all from Japan, gives a clear read on what the app is for and on the trend break. But most individual failure themes rest on one or two reviews — the volume-slowness report, the multi-parcel gap and the sync lag are each n=1 and uncorroborated, so I cannot tell whether they are widespread or store-specific. The two support/billing complaints are only n=2, though the developer's own repeated admission of an email fault corroborates them independently, which is why I treat that as a red flag rather than noise. Integrity also caps this: the October 2022 cluster reads as invited feedback and one five-star reviewer was in a 1-yen shipping campaign. No review states a price, so I cannot judge cost claims in absolute terms, and 佐川急便 is in the app's title but absent from every review, so reviews give no evidence about it at all.

What will annoy you

Validation errors on unusual names, old-form characters and addresses, with the error location not identified so you re-enter blind. The carrier API accepts only ShiftJIS-range characters, so this is a permanent limit rather than a fixable bug: 3 reviews, steady, last seen 2026-05.

How the developer behaves when it breaks

Replies to about half of negatives (reply_rate_negative 0.5), but not the ones that matter most recently. The two billing/tier complaints got prompt, apologetic replies (1942 within a day, 4851 within six days) — both essentially the same template blaming a mail-receiving fault and pointing to a ticket form, neither confirming a fix. The detailed May 2026 1-star (3081), the March 2026 multi-parcel 2-star (6377) and the April 2026 1-star (6681) got no reply at all. The edited 1-star 4922 shows only 2023 and Feb-2024 replies against a March 2026 complaint; the surviving useful part of that reply is the explanation that the carrier API accepts only ShiftJIS characters, so old-form-character errors are by design. Tone and depth have dropped: 2022–2023 replies answered each feature request point by point with dated commitments (7174, 6478, 0875, 5619), whereas 2025–2026 replies are short thank-yous (6821, 4300, 5582). On the positive side, dated promises were kept, slowly: chilled shipping promised in the 0875 reply for early 2023 and confirmed live by 8555 in 2024, and label cancellation requested in 2022 and confirmed working by 8805 in July 2026.