The Application User Interface (UI) makes up the graphical component of the billing system and provides a simple user-friendly way to interact with the billing system. Typical use cases include entry of accounts, entry, and management of customer information, payment method configuration, product catalog management, and management of discounts, orders, and subscriptions. The application UI typically provides the means to configure and manage the billing system environment and control user and role permissions.

An API or Application Programming Interface is the key to inputting or retrieving data in a billing system from an external system. APIs typically correspond to tables inside the billing system’s database. APIs are made available by a billing system vendor as a way to facilitate integration and safe and secure access to data or metadata pertaining to billing.

An API is the only way to dynamically access billing data outside the billing system, these APIs can be used to integrate billing processes or information into an existing system or website. Customer self-service, e-Commerce, and partner channels all require APIs to integrate and connect with the billing system. APIs require network connectivity with the billing system and must be authenticated and authorized before access to the billing system will be permitted.

APIs are designed in a way that any application that can process a simple web request will be able to utilize them. The standard HTTP requests framework provides for a universal way of interacting with the billing system using standard methods of web communications (GET, POST, others). APIs are sometimes referred to as web services for their part in allowing connections between systems over the web.

Workflow, particularly workflow automation, is a set of tools and methodologies that facilitate the efficient communication, and processing of data between people or systems. Its function with regard to a billing system is to provide the means to interface between the billing system and other systems or processes that are not supported by the billing system out of the box. Workflow can be internal or external to a billing system and provides dynamic, expanded, or reactionary functionally not offered by the core-billing engine. Such functionality includes approvals, custom logging, accessing third-party data, event/webhook-based actions, custom wrapped API endpoints, and custom served user interfaces among others.

Workflow tools typically provide a method of graphically representing all steps in a workflow including data elements, data transformations, integrations, tasks, and notifications.

ETL – Extract, Transform, and Load – refers to a method of getting information from a source system into a target system, and is a critical component of system implementation and replacement projects. ETL is a vendor-agnostic term for the generic process of gathering data, objects, resources, or information from a source system, modifying it to a format understood by the target system, and then moving or loading it into the target system.

Data extraction is facilitated by available reports, export tools, and APIs in the source system. The format of the source data is typically not consistent with the target’s requirements and therefore requires treatment before it can be used as input.

Billing system migrations often require extensive ETL work that is typically accomplished by ETL tools, database manipulation tools, workflow, custom programming, and APIs.