A discount the promotions cannot express
The customer asks: A member rate that multiplies with a promotion, taken after it
- Verdict: Ready, with limits (5)
- Door: Sandboxed function · area: Prices and promotions › Member prices
- Recipe: The Wasm kit — write, test and publish a sandboxed function
- Sample: tools/wasm_kit/template
- Checked: carried 2026-10-15 · not re-run
What you build
Your sandboxed module takes money off a line after every promotion, on the server and on the till offline.
Limits
- Installing the certified module on a shop, step by step: recipes/configure_no_code.md, A member rate after the promotions.
- It runs only once CitiXsys has certified your module, the shop's administrator has added it in Desk, and the shop has raised its limit above 0.
- It is never offered a line a pricing rule has already priced, a return or a gift-card line.
- The Desk POS does not run it: a sale rung there is priced without your module.
- A function that runs on a till is compiled from Rust; one that runs only on the server may be JavaScript.
Tell the customer
The extra rate is applied after the promotions, on the till too, once our certification and the shop's own limit allow it.
What next
- Tell the customer the 5 limits above, and write them into the proposal.
- Start from: The Wasm kit — write, test and publish a sandboxed function.
- Copy the sample: tools/wasm_kit/template, 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.
Run it on the till offline as well as online: it must give the same answer.
Related needs
- Members pay less, by tier — Ready, with limits (5)
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