OWASP recently announced the API Security Top 10 Release Candidate. Read more about the OWASP API Security Project (and check out presentation deck in the Quick Links section). Here is the top 10:
API1 - Broken Object Level Authorization
API2- Broken User Authentication
API3 - Excessive Data Exposure
API4 - Lack of Resources & Rate Limiting
API5 - Broken Function Level Authorization
API6 - Mass AssignmentAPI7 Security Misconfiguration
API8 - Injection
API9 - Improper Assets Management
API10 - Insufficient Logging & Monitoring