The vision of the Semantic Web and its concepts represent the future of the Web. Application programming interfaces (APIs), which simplify the integration of semantic technologies, are an important part in realizing this vision. The Resource Description Framework (RDF) defines one of these semantic technologies, which is used to describe the resources of the Web to make them interpretable by machines. While RDF APIs are getting more popular amongst programming languages like Java or .Net, there is still a lack of efficient and satisfying RDF interfaces for PHP. Considering that PHP is the fourth most used programming language for Web development, it is necessary to provide usable interfaces. Therefore, we decided to create an easy to use RDF API for PHP, namely, the ''Easy RDF for PHP (ERP)'' API. By evaluating and comparing popular RDF APIs from various programming languages, we were able to extract strengths and weaknesses, which were considered during the development of our API. This enabled us to introduce valuable, but previously unused concepts to PHP, creating an efficient and easy to use API. Further, the comparison illustrates that most APIs do not provide efficient and satisfying interfaces for RDF. In a final comparison, it is illustrated that the ERP API achieves high ratings in the characteristics efficiency, effectiveness and satisfaction and, therefore, it presents opportunities for the development of other APIs.