1) Securing your back-end APIs - If you have a legacy back-end web service that has a basic authentication scheme, you can add some additional security by placing APIM in front, and requiring subscription keys. Leverage your existing firewall to ensure only your APIM instance can communicate with your back-end API, and you've basically added a layer of protection.
2) Lift and shift - there are always going to be clients that don't want to update their clients to use a newer API; in some cases you can make a newer API look like an older one by implementing some complex policies in APIM. You can also do the opposite, making older APIs look new, such as making an XML back-end accept both JSON and XML.
3) Centralizing your APIs - if you've acquired another company and want to make their API set look as if it's a part of the larger whole, APIM is an easy way to provide a consistent front-end interface for developers.
Makes our life easy as application admins in securing our applications and making them accessible. We can easily add an application within a few minutes and define the backend servers right away.
Lack of robustness is a bit of an issue. Several other providers offer more options and capabilities, but then, they are lacking in interface ease.
As with anything Azure, pricing is really hard to stay on top of. I always find that you really don’t know what you’re paying for until you get the bill. Having an excellent Azure Administrator can help resolve that.
Integrating with app services outside of Azure can be a challenge, or at least much more challenging than just using Azure App Services.
We had an issue after upgrading from RHEL 7 to 8, and there were some issues that the security team imposed upon the platform with a scanning tool. We also had a VXLAN environment that was not properly sending a gratuitous arp to the network. NGINX support was instrumental to speedily resolving our issue.
We are planning by using NGINX it can greatly reduce our OPEX by 50% "just our own running APIGW" the cascading effects in the long run will be much more.