API Developers have a lot of responsibility while creating resourceful and robust APIs. While strategists and planners will put forward their demands on the table it is the API developers that face the real heat in bringing the plans on paper to life. There are a lot of API resources available today to ease the development process however, there are some key security issues that must be paid attention to.

1. OAuth is an important element of API pertaining to application authorization. OAuth basically enables an application and an API to interact with one another, being fairly easily and manageable. It also plays an important role in managing authorization as it holds the ability to change and update authorization of the application providing overall control to the owner of the application.
2. Enabling your mobile application on various mobile platforms is an altogether different task that requires prime attention because mobile applications access data in different ways. Therefore, it is extremely essential to adopt measures that ensure same level of safety for APIs in all mobile devices being unique to all platforms at the same time.
3. REST is the most quintessential software architecture in APIs as it aids the client-server relationship maintaining all the prerequisites of a resourceful API such as Scalability, uniformity as well as Customizability at the same time.
4. Authentication is yet again a very important aspect to be considered as apps that will communicate with the API must be authenticated.
5. Cryptography is coding the key pairs and certificates. An API must provide efficient built in PKI system to generate and distribute public/private key pairs. It must also provide policies unique to different type of message encryption and coding standards.
6. Creating an API License is another step for ensuring security as users of your API will need to comply with the terms of the license. It can be used to authenticate the system and provide you with alerts when users try to use the application beyond their allotted scope of its use.
7. API developers or the community must employ a data monitoring tool that works with Java or TCP/IP monitoring to figure out what data is being accessed and by whom to give you a clear insight as to where your data is going.

Knowledge of these topics provided in the list may not be conclusive but provides a prime knowledge about all the security issues and terms which are essential while developing and handling APIs.