Duplicate Functionality – When more than one PIs perform the same function.
Compatibility – When APIs don’t work well with certain platforms, frameworks, or languages, leading to integration issues.
Missing Functionality – When a requirement is not fulfilled by any of the APIs developed.
Error Handling -When APIs don’t provide correct error messages for unexpected/invalid requests.
Security – When APIs are accessible to unauthorized users too.
Reliability – When APIs may not be available at all times.
Performance – When APIs take a long time to respond, it could be at an increased load.