A price list worked out from another
The customer asks: A selling price list worked out from another (a multiple of the buying list, wholesale as a share of retail) and kept in step
- Verdict: Ready, with limits (7)
- Door: Outside app · area: Prices and promotions › Price lists
- Recipe: A price list worked out from another, kept in step
- Sample: S26 — Derived price lists (a price list worked out from another, kept in step)
- Checked: run on a sandbox 2026-10-16 · POS 2.0.0.648 · a source change followed in 14 s, the shop's pricer read the new price, a person's price held, a deleted source ended its row in 15 s, reconcile 0
What you build
An outside app follows price changes on the event feed and writes the derived list's item prices through the record API, by a rule the shop keeps: a factor, an offset, a rounding step and a floor.
Limits
- The new price arrives seconds after the source is saved (14 seconds on a sandbox; about a minute at worst when the shop's background worker is busy, chapter 5); a sale in those seconds is priced at the old one, and a till takes the new price at its next sync.
- A price a person set on the derived list, or changed there after the app wrote it, is kept and listed, never overwritten; a list that already has prices keeps them, so derive into a new list or end those prices first.
- Only prices for everyone are derived: a price for one customer, one supplier or one batch is left alone.
- Both lists are in one currency, and one list is written by one rule; a loop of lists is refused.
- A promotion or a member discount still applies on top, as always.
- Run one copy of the app per shop.
- The price list record has no formula field (read on a sandbox), and a selling pricing rule is refused (chapter 4), so this is an app, not a setting.
Tell the customer
The derived list follows its source within seconds of each change (about a minute at worst on a busy shop), by the formula, rounding and floor you choose; a price someone sets by hand on it is kept, and the nightly check lists it.
What next
- Tell the customer the 7 limits above, and write them into the proposal.
- Follow the recipe: A price list worked out from another, kept in step.
- Copy the sample: S26 — Derived price lists (a price list worked out from another, kept in step), and change it.
- Build and test it on your sandbox (request one if you have none; what is on it).
- Run the checks: your own tests, the kit's checks and the money kit's release gate (testing and release).
- Release through the customer's own release gate (14. Testing and release); an app other shops install goes through the App library.
Stop your service for a while and start it again: it must catch up from the event feed, missing nothing.
Related needs
- A price checker shoppers use on the shop floor — Ready, with limits (1)
- A price list as a document with a photo for each item — Ready, with limits (4)
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