I wonder how Saas companies like Zapier, Zendesk, etc...build a lot of common 3rd party integrations that perform the same set of tasks. I mean, do they just brute force in building those market place integrations or do they have an architecture where everything just works if the API keys are configured?

Eg: github, gitlab, Jira apis kind of do the same set of tasks but their APIs are different in structure. Is there a normalisation technique behind the scenes or they just build the same stuff 3 times.