Two apps doing the same job in almost the same way. The real difference is how the bill is counted — and there are things Lumi does that Altfield does not do at all.
Lumi and Altfield both scan a catalogue, draft the missing fields, show them to you, and write only what you approve. Anyone telling you one of them is the safe one and the other is reckless has not used both. What differs is the unit you are charged in, and how much else each app does.
Altfield charges per product, counted once per run however many fields that run writes. Lumi charges in credits: one credit for an alt text, an SEO title or a meta description, two for a product description, with categories and metafields counted once per product. Neither is a trick. They suit different shapes of work.
| Altfield | Lumi Catalog | |
|---|---|---|
| Free tier | $0 — 25 products a month, every feature | $0 — 100 credits a month, 10 products a batch, missing-content check on the top 100 products |
| Paid entry | $19/month — 750 products a month | $19/month, or $190/year — 500 credits a month, 50 products a batch |
| One-off option | None. If the job is finite, run it on a paid month and cancel. | $79 once — 3,000 credits, valid 90 days, no subscription |
| What you count | Products. One product, one count, however many fields. | Credits per drafted field. Regenerating a draft costs more. |
| Approval before writing | Always | Always — this is not a difference between them |
| Undo | One click per run, restores the exact previous values, makes no AI calls, free on every plan including after you stop paying | Restore for eligible changes, plus CSV export of published changes |
| Languages and voice | Written from the product's own text, as it is written | 17 draft languages and a brand-voice setting on paid tiers |
| Page accessibility scans | None. Altfield fills product fields and nothing else. | Yes, with scan history and new-issue alerts on Maintain |
| See your gaps before installing | No. The gap count is the first screen after you install, on the free plan. | Yes — a free sample scan of public pages, no install |
Lumi's figures were read from their own pricing page on 6 November 2026, where they were marked last verified 26 October 2026. Check them before deciding — both apps change.
Lumi publishes this one: 250 products, all four copy fields, three images each. By their worksheet that is 1,750 credits.
That is the honest shape of it: the more fields you want per product, the better Altfield's meter reads. The fewer, the better Lumi's does. A thousand alt texts and nothing else is 1,000 credits on Lumi: two months of Maintain, or a third of one $79 Cleanup. On Altfield the same job is 1,000 products, which is a $49 month rather than a $19 one.
You want to see your gaps before granting any app access to your store; you need drafts in a language other than the one your products are written in, or in a defined brand voice; you want store-page accessibility scanning as well as product fields; or the job is finite and you would rather pay $79 once than hold a subscription.
You do not want to do credit arithmetic before you start; you want several fields on each product rather than one field on many; you want every feature on every plan, including the free one; or you want an undo that costs nothing, needs no AI call, and still works after you have stopped paying.
Run it on your own catalogue and judge the output, not the comparison table.