View Issue Details

IDProjectCategoryView StatusLast Update
0010642Talerwallet (iOS App)public2025-11-22 17:23
Reportervecirex Assigned Tovecirex  
PrioritynormalSeveritytweakReproducibilityalways
Status assignedResolutionopen 
Summary0010642: When making minimum possible payment, UX questionable; and: fee seems to be charged
DescriptionThis is from a payment test on the iPhone (newest version v1.2.0 as released yesterday) and different observations can be made when trying to transfer CHF 0.00000001, the minimum possible amount an order could be created for:

- A fee is shown (there should be no fees for TOPS/CHF, as of 2025/2026 at least)
- The numbers in the UI are shown as with as footnotes markers or mathematical powers to a zero base being shown as floating no. "0.00"; it's in any case not understandable whatsoever (for normal human beings)

See screenshots attached, also to check for the sums. The final amounts I still have in my wallet seems incorrect (perhaps because of fees?)
TagsNo tags attached.

Activities

vecirex

2025-11-21 14:57

manager   ~0026568

typos

vecirex

2025-11-21 15:00

manager   ~0026570

Reposting screenshots, as I used .pdf instead of .png endings; leading to rendering issues here, even if endings should not matter in UNIX systems. :)

vecirex

2025-11-21 17:33

manager   ~0026573

Last edited: 2025-11-21 17:36

clarify: mentioned amount is CHF (also clear from screenshots, however) and the fee charged seems to be 24,999x times that amount; and: the final sum seems to reflect the money went to the exchange, indeed

vecirex

2025-11-21 17:41

manager   ~0026574

@stefan: Even if this gets fixed entirely, test cases to avoid this for any production system are needed to see for which ranges / at which threshold fees start to be applied, and when this happens how they apply in relation to the amount in question; maybe this also only happens under certain circumstances of the orders created, no idea.

In any case, for much higher amounts, like CHF 0.01, CHF 0.1 or even francs I never saw any fees being applied and deducted from any of my wallets.

vecirex

2025-11-21 18:02

manager   ~0026575

clarify broken text in descr, "zero based"; extend a bit

MarcS

2025-11-22 16:08

developer   ~0026578

That's easy to explain: Fees are just the difference between raw and effective.
You want to pay less than the smallest denomination available. Then the wallet pays 1 unit of the smallest denomination, which means your payment is fulfilled and the difference is shown as fee.
==> You can never pay less than the smallest denomination.

The rendering of digits less than 1 Rappen with SuperScriptDigits is absolutely correct, see DD51 Fractional Digits.

Issue History

Date Modified Username Field Change
2025-11-21 14:56 vecirex New Issue
2025-11-21 14:56 vecirex File Added: taler-merchant-iphone-payment-minimum-amount-app-ux.pdf
2025-11-21 14:56 vecirex File Added: taler-merchant-iphone-payment-minimum-amount-backend.pdf
2025-11-21 14:57 vecirex Description Updated
2025-11-21 14:57 vecirex Note Added: 0026568
2025-11-21 14:58 vecirex File Deleted: taler-merchant-iphone-payment-minimum-amount-app-ux.pdf
2025-11-21 14:58 vecirex File Deleted: taler-merchant-iphone-payment-minimum-amount-backend.pdf
2025-11-21 15:00 vecirex Note Added: 0026570
2025-11-21 15:00 vecirex File Added: taler-merchant-iphone-payment-minimum-amount-app-ux.png
2025-11-21 15:00 vecirex File Added: taler-merchant-iphone-payment-minimum-amount-backend.png
2025-11-21 17:33 vecirex Description Updated
2025-11-21 17:33 vecirex Note Added: 0026573
2025-11-21 17:36 vecirex Note Edited: 0026573
2025-11-21 17:41 vecirex Note Added: 0026574
2025-11-21 18:02 vecirex Description Updated
2025-11-21 18:02 vecirex Note Added: 0026575
2025-11-22 16:08 MarcS Note Added: 0026578
2025-11-22 16:09 MarcS Assigned To => vecirex
2025-11-22 16:09 MarcS Status new => assigned