QoinPro supported numerous forks starting from 2017. Examples include Bitcoin Cash (BCH), Bitcoin Gold (BTG), Bitcoin Diamond (BCD), UnitedBitcoin (UBTC) and others.
Most forks did not gain traction in the community or otherwise failed and have since been delisted from QoinPro. The last fork to get delisted was Bitcoin Cash (BCH), although withdrawals for BCH can still be made until December 31, 2021.
Checks for address balances, as well as the awarding of forked coins was a manual and labor intensive process resulting in a significant number of support requests.
Lesson learned: Don't introduce manual processes when there is large userbase. Its labor intensive and overwhelms support.
With the addition of new forks and later on Airdrops/Airdrips, many users started creating fake accounts in order to grow their network and benefit from additional rewards. The scale at which this happened took us by surprise. Hundreds of thousands of accounts had to be suspended which took a significant amount of time.
Lesson learned: Assume there are always some users that will try to exploit freebies. Protect from the beginning otherwise support will be overwhelmed.
Growing to the first one million users was exciting, but it also introduced significant scalability issues. QoinPro started as a side-project and the code-base and database design did not anticipate such growth. It took until 2018 before the scalability issues were finally resolved.
Over the years the scalability issues have resulted in intermittent (but recurring) connectivity and availability issues.
Lesson learned: Develop and Design a platform with millions of users in mind.