[4] These services are provided via the use of custom software development kits (SDKs) and application programming interfaces (APIs).
Web and mobile apps require a similar set of features on the backend, including notification service, integration with social networks, and cloud storage.
[11] BaaS providers form a bridge between the frontend of an application and various cloud-based backends via a unified API and SDK.
Alternatively, clients can pay a set fee for a package which allows for a greater number of calls or active users per month.
[29] Another business model that has been used by a lot of BaaS providers is PAYG (pay as you go),[30] which has a flexible cost based on developers' usage of database, storage, bandwidth, function calls, user numbers etc.