Apple Business Manager. How do we revoke a code or license? We are not using a MDM The small dev company that I work for has been contracted to build an app for client. This client is using Apple Business Manager and wants us to publish to it.

I have built the app and deployed it for review to the Apple Connect. It passed and I see it is now in the client's Apple Business Manager account.

Here is where I am confused. Our client DOES NOT have a MDM. How can I use Apple Business Manager in this case?

Initially I thought I could simply use redemption codes, but now I see that this is not going to work, as redemption codes are similar to "gift cards" that we give out to people. Unless I am mistaken, there is no way to manage them and revoke them when we need so.

It seems that the only way to manage the licenses is to implement a MDM (like Mobile Iron, etc.), but this seems like a lot of work.  There must be another way.   What about contractors that require a corporate app? Surely, there has to be a way to use the Managed Licensing aspect of ABM without using a MDM.

How can use ABM to do "managed licensing" without our client(s) having a MDM. Is there a way that I can revoke a redemption code once I have issued it?
The ordinary way to do what you want is to use MDM.

If you do not want your client to setup MDM, then the only way to do this is by adding a login system to your app. This way you can have employees of your customer install the app via the App Store using redemption codes, and then be able to stop them from using the app by invalidating their login.

To make matters easier, you could implement the initial login in the form of a link for the employee to follow (similar to the link used to redeem the app), it could be a QR-code to scan or a simple username/password.