Cloud computing has emerged as a distributed computing paradigm where resources are requested on demand and in a very dynamic fashion and paying only for what you consume. This new paradigm created an ecosystem where several providers offer heterogeneous computing resources to satisfy the customers’ computing demand. So, the allocation and adaptation of this demand to the correct resources is a key issue in this ecosystem, because it can produce a mutual benefit for the customers and providers. However, with the wide variety of customers and providers, this allocation is not an easy task. This chapter presents a toolkit that implements a methodology for improving the resource allocation between different Cloud providers. The Semantically Enhanced Resource Allocator (SERA) toolkit introduces the semantic web and multi-agent technologies for facilitating the interoperability between the users and different resource providers. Semantic web technologies provide the required semantic interoperability between the different providers’ vocabularies; meanwhile a platform of configurable agents provides an adaptable and autonomous way of allocating and managing execution requests and resources according to the customers and providers rules.