Hi Noah,
Really depends on how your company API is secured. Since you mentioned OAuth, the traditional mechanism for backend API to backend API is via client credentials auth workflow. You generate client credentails like a client_id and client_secret within your identity provider, store those values within the Q2 platform (we use a secret management tool called vault https://docs.q2developer.com/guides/performance_and_security/vault.html). Then at request time, the client_id and client_secret are exchanged with your API to get back a access_token, which is then used on subsequent reqeuests to your API.
Hope this helps.
Jason