This post is in response to this Stackoverflow question.

Years ago, someone asked on Stack Overflow if it were possible to retrieve a list of all employees who work at a company. I can do this through the LinkedIn UI, but I cannot seem to find any mechanism for this using the v2 API. The SO response mentions this used to be possible on the v1 API, but you had to request access through LinkedIn's "Vetted API Access Program." Unfortunately, the link on this response is now obsolete and does not send users to any such program.
How could I apply for this program nowadays? This is a specific situation to me and my company, so I would very much like to discuss this with someone at LinkedIn if some form of this Vetted API Access Program still exists. I do not wish to disclose the details of this request to the open internet.

Our answer

In general, you can get a list of employees of a company if you scrape Linkedin profiles exhaustively, or if you have an exhaustive dataset of Linkedin profiles.

Each Linkedin profile contains a list of experiences that links to the company profile URL.
Thereafter, you will filter the dataset into profiles currently working at X company to get a list of employees currently working in a company. The same technique can also be used to retrieve a list of past employees.

And that is what we did. We scraped all public Linkedin profiles based in the US and made an alternative API known as Proxycurl Employee Listing API to Linkedin API to provide employee listing functionality.

Proxycurl's Employee Listing API will never be as exhaustive as Linkedin's dataset because not all profiles are made public, but most are. But will suffice to meet your needs.