Do you know developers' tool with nice affiliation program?

Gumroad is great but you might find difficulties when configuring your software for sale. The platform is more tuned for sales of digital content.
If you are selling software, I suggest that you use an e-commerce provider that is specialized in software sales.
I have reviewed the major players here
https://www.starmessagesoftware.com/e-commerce-software-publishers
so I can select one for my own sales.

There are a few winners and I decided to go with PayPro global
https://www.starmessagesoftware.com/e-commerce-software-publishers/paypro-global.com
that also has its integrated affiliate network.
The payment to the affiliates is done by PayPro and you do not need to spend any time on it.
You will only need an "affiliates" introduction page, like
https://www.starmessagesoftware.com/affiliates.html
but I am sure you can do it much nicer.

Affiliate networks give you also the opportunity to become yourself an affiliate of complementary software to yours and make more sales from your website, if you have traffic with users interested in the domain of your software.

The quick answer is to use gum road- it provides affiliate links that stay in cookies on someone's computer so the affiliate will get the sale up to 30 days after the user initially visits.

Unfortunately, the answer is a lot more grim when using Stripe, which is what I use for Codemochi, my website. I could easily implement a coupon code to provide a discount and that would be specific to an affiliate.

The problem is how to actually pay the affiliate. What's so nice about gumroad is that they will split up the earnings between you and the affiliate and then you only have to worry about taxes for your portion of it and the affiliate pays taxes on their portion of it. For Stripe, all of the money goes into your account so first of all you pay 100% of the stripe fees on the full amount, which isn't so bad but then you need to take a portion of that and pay it out to your affiliate using some other service. I don't have a clue how that sort of transfer works for tax purposes- am I paying taxes on the full amount and then deducting what I pay off as an expense? No idea.

I actually reached out to stripe to ask whether their stripe connect would work and while it would in principle it is really designed for people building a marketplace- so the business model is actually inverted from what we want for an affiliate program. The problem is that the connect is designed for many sellers who sell their goods and then the platform takes a cut, in our case we have 1 seller and then a number of "marketplaces/affiliates" which take a cut. In the event of a return the seller is responsible for paying all of that, while for the affiliates model we shouldn't burden them with that process. Stripe connect does provide a different connect model that puts the burden back on the seller like it should but they have a monthly charge per affiliate to provide that service, which also is not ideal.

Since Stripe doesn't seem to solve the problem, when you start looking around at other affiliate marketing platforms that have plugins with stripe, they all will manage the affiliate portion of it without touching the money- so that means that they will tell you how much you need to pay out to each affiliate, but its up to you to actually pay all of those affiliates using paypal or some method and then figuring out all the tax implications yourself.

What a mess right?! If you don't take the easy route and go with gum road, I'd love to hear how you exactly figure this out with stripe. Cheers!