The question doesn't make sense. JIRA provides SOAP and REST interfaces to you. It's other applications that use those interfaces. JIRA can be made to talk to other systems too, and it uses all sorts of interfaces to do that, but you'd have to consult each integration point to find out what it's doing, that's not "JIRA using API"
If you're just asking if they're available in JIRA
SOAP: Yes, up until 20th July on Cloud, when it's going to be turned off. So you've got 10 days. It will be removed from version 7 of JIRA too
REST: Yes, this is available and will continue to work
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