The term cloud computing can be defined as “a system that is concerned with the integration, virtualization, standardization, and management of services and resources”. The benefits of cloud computing include minimized capital expenditure, utilization and efficiency improvement, high computing power, location and device independence and finally very high scalability . Cloud computing brings a scenario in the field of IT that gives a model where a user who wants to gain access to the software without licensing it, platform to run this software and the infrastructure can access these services on pay-per-use basis. The cloud platform also provides a large amount of data storage to the user who can utilize it. Moving data into the cloud offers great convenience to users since they don’t have to care about the complexities of direct hardware management. The pioneer of cloud computing vendors, Amazon Simple Storage Service (S3), and Amazon Elastic Compute Cloud (EC2) are both well-known examples. Different approaches have been investigated that encourage the owner to outsource the data, and offer some sort of guarantee related to the confidentiality, integrity, and access control of the outsourced data. The user who gain access to the cloud service gain all these services but the user gets vendor lock-in and has to use all the service by this particular cloud service provider if users want to gain access to another cloud service provider for more effective and low cost management user has to authenticate to a particular service provider in this way user has to use multi-service provider on individual basis and pay separately for the service to each provider. The scenario of multi-cloud presents a model called collaboration of multi-cloud where the user vendor lock-in can be abolished with an agreement between the various cloud service provider that an authorized user of a particular cloud service provider can gain access to different service provider as per his requirement and cost management. To avoid the vendor lock-in syndrome, SaaS must be portable on top of various cloud PaaS and IaaS providers. This portability allows the migration from one provider to another in order to take advantage of cheaper prices or better qualities of services (QoS).