Excuse the simple question: When I hear "microservices", I think serverless backend. Is that right, or are they different? If they're the same, how do you stream video with serverless? (Seems like streaming, websockets, etc... shouldn't be possible in a serverless environment...)
"Serverless" describes how a deployment artifact is deployed and runs. Generally it refers to a class of technologies in multiple domains whereby intricate knowledge of the underlying host is abstracted behind a cleaner API, with things like scaling, security, patching, etc handled by an infrastructure provider. While the term rose in prominence alongside "functions as a service", which is certainly a technology that generally qualifies as serverless, there are many serverless products out there: AWS Fargate for running containers, DynamoDB for a database, S3 for object storage, all of these are "serverless". A good signal is: if I can SSH into it, its not serverless.
A microservice can certainly be deployed serverless (ECS/Fargate or Google Cloud Run comes to mind). A microservice can even refer to one or more logically related functions-as-a-service; the term more-so speaks to how the engineering teams organize their business domain into the code and how the APIs speak to each other, rather than the exact underlying technologies.
Like, instead of having the video decoding and the analytics code in the same monolith attached to same DB, you deploy a different server for each one, generally with a new DB for each. When the services need to talk to each other, they do it via network (REST, gRPC, etc.).
e.g. the Friends feature on Twitch is one microservice, running in its own autoscaling group, with internal APIs used by other microservices like Whispers.
Not necessarily a good idea, but one 'feature' of microservices is the ability to pick different stacks, languages and delivery methods on an individual service level.
We literally have services that are run entirely using AWS Lambda functions only.
This is a pretty big difference from teams I've worked on in the past, that have 8 engineers all working on a singular service.
"Microservices" is more of a philosophy than anything.