Fee is incorrectly calculated for non-approved ERC-20 assets (applies to all networks)

[pavloburykh]

Reproducible on Desktop as well (verified in Desktop build from this PR status-im/status-desktop#17840)

Link to discord discussion

Steps:

1. Go to Swap.
2. Select a non-approved ERC-20 token in the “Asset to Pay” field.
3. On the swap setup page, build a route and check the estimated fee.
4. Proceed to the approval confirmation screen and check the approval fee there as well.

Actual Result:

• On the swap setup page, the estimated fee only reflects the approval fee, ignoring the swap fee.

Video from Mobile

fee_estimation.mp4

Video from Desktop

screencast.2025-04-25.17-10-12.mp4

Expected Result:

• Swap Setup Page: If the selected ERC-20 asset is not approved, the estimated fee should be: Approval fee + Swap fee
• Approval Confirmation Page: Fee should show only the approval fee
• Swap Setup Page: If the asset is already approved, the estimated fee should be: Swap fee only

Logs (Mobile):

https://drive.google.com/file/d/1dHZuVO68Uzjm3W4K4rfTwv4904d7pQhc/view?usp=drive_link

OS: Android/IOS/Mac OS Desktop
build: nightly

[anastasiyaig]

I think the calculation overall is wrong compared to Velora itself

[saledjenic]

The difference in destination amount is coming from this function https://github.com/status-im/status-go/blob/develop/services/wallet/router/pathprocessor/processor_swap_paraswap.go#L135-L150 where we subtract our partner fee, which is 0.7%, from the destination amount.

This is a swap flow run in the Status app comparing the details with https://app.velora.xyz

This is a proposal coming from paraswap, where we can see that the destination amount is the same as on https://app.velora.xyz

This is a tx https://basescan.org/tx/0xeeeb271d09d653cc5473484e5d6a7198a8859b89255fbc2494d1e801ad92ffef where we can see that the received value is exactly the same as displayed in the app:

Based on all that, this is not an issue, but the way we're calculating the destination amount.

[pavloburykh]

@saledjenic I think we are speaking about different issues, please see the description of the current issue, it is about estimated fee on Swap setup screen, which reflects only approval fee (in case approval is required). Expected result - it should show Approval fee + Swap fee.

This issue is still valid, both on mobile and desktop.

[churik]

@anastasiyaig @saledjenic

I think the calculation overall is wrong compared to Velora itself

if you mean the receive amount in Swap, that's a separate issue here: #22536

Issue in description is that the estimated fee only reflects the approval fee, ignoring the swap fee, though I'm not sure about the requirements regarding that.

[anastasiyaig]

got it, thanks for details

[churik]

Ok, added a link to a discord discussion which it is coming from, hopefully it is clearer now

[pavloburykh]

Hey @alwx! Since you're working on integrating status-go#6568, I'm assigning this issue to you, as it should be resolved once that integration is complete.