API

An Application Programming Interface (API) is a set of definitions and protocols for building and integrating application software. In the context of B2B SaaS, APIs are the glue that holds the ecosystem together.

They allow different SaaS tools to talk to each other (e.g., your CRM talking to your email marketing tool). Offering a robust API can be a major selling point for a SaaS product, as it enables customers to integrate the tool into their existing workflows and tech stacks, thereby increasing stickiness.