I want to make my own crypto gate and I'm looking for readymade software solutions for that.

I’m looking software solution for a payment gateway with integrated web crypto wallet.
Here are my main use cases:
1. A merchants who want to accept payments integrates his website with my API. When his client wants to top-up a balance merchant will send him to my website so he could buy crypto using credit card and pay merchants invoice. After that I will send the client back to the merchants website.
2. A user registers on my website, passes KYC process, purchases crypto using credit card and gets this crypto to a custody wallet inside my website, then he can send this crypto to an external wallet.
3. A user registers on my website, top-ups his custody wallet inside my website with BTC, purchases ERC20 token from me paying with BTC, and sends this ERC20 token to an external wallet.

Functionality I need:
1. Payment gateway - merchant API, invoicing system;
2. Custody web wallet - support of ETH, ERC20, BTC needed. Something similar to blockchain.com web wallet. Integrated custody solution similar to Bitgo is preferable, but proprietary crypto custody solution with own nodes will also be considered;
3. Buy/sell functionality - so users could buy and sell crypto from me paying with credit card or with another crypto;
4. KYC process - client forms and admin panel, ideally with integrated third party KYC service;
5. Admin panel.

Here are couple of examples:
1. https://www.merkeleon.at/crypto-payment-processing/
2. https://coinspaid.com/processing/

I’m looking for open source or proprietary software solution for web wallet with integrated exchanger and payment gateway. It can be a whole project with all parts described below or separate parts that we will integrate.
If it will be proprietary software I want to buy source code so that my team could do further development independently.

I need such parts of the project:
1. Web wallet - the same as this login.blockchain.com or walletesvoe.com
2. Multi-currency custody wallet with API - something like BitGo Hot Wallet. Support of ETH, ERC20, BTC needed;
3. Exchanger functionality - so users could exchange crypto to crypto, as well as buy and sell crypto for fiat - the same as in login.blockchain.com;
4. KYC process - client forms and admin panel, ideally with integrated third party KYC service;
5. Crypto payment gateway - merchant API, invoicing system (use case - merchant registers its client in our system with API and redirects it to our website; in our web wallet clients buys crypto and pays merchant with crypto; clients gets back to merchants website);
6. Admin panel.

Thanks for the advice!

The problem is that they just don't respond on their support email.

Thanks! That's what I'm trying to do now.

Looks like it's 2) or may be 1) because my phone is 100% functional.
I just hope GreenAddress people are reading this forum and will eventually try to solve my problem.

Trying to send my bitcoin in GreenAddress wallet with 2FA by SMS enabled, but don't get an sms code to my phone. The problem persists for a week already. Support representative answered that he can help to solve that 5 days ago and then disappeared and not answering my email any more.

It's obvious, the question wasn't about that.

Taas, how can we check that your counter isn't a lie? I tried to check balance of the account your Dashboard gives me to invest to - it's 0.