How Big Should Microservices Be?

Another frequently asked question about microservices this week, and it's a doozy one. How big should microservices be?

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Thanks
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I used some royalty free resources, including:

[charliejade]

Here's a question -

If there is only one 'microservice' and it singlehandedly encapsulates the 'entire' business problem, can it still be considered a microservice, given there is only 'one'?

[ukaszStachowiak]

Good to see you, friend! I will follow your channel, thanks for useful stuff ;) all the best!

[BerkeSokhan]

That dial needs an eleven!
Great video and great background Sam, hope more to come. Subscribed!

[jvm-tv]

I wish could have a view of the size of microservices in mature companies like Netflix, Uber etc.

[rwang]

Maybe if everyone starts to embrace FaaS, microservice implementations will tend to gravitate towards FaaS. Number and size will finally become the meaningless metrics that they really are. The correct metric seems to be how well we can independently deploy microservices / FaaS.

[DavidAtTokyo]

100% agree that the "micro" in microservices sets people off in the wrong direction. That's ok though if they read Sam's book because those'll sort them out!
On a similar note, I watched an Eric Evans talk from circa 2015. He was excited about microservices because, not because they are small, but because of the hard boundaries that they afford. Compared with a modular-monolith architecture, he made what I think was a great point that, over time, (well designed) microservices with their hard boundaries around them to protect their models from corruption, stand a better chance of maintaining their modular integrity. For with a logical "modular" boundary inside a monolith, there is not much to stop a developer coming along and breaking the rules of the logical boundaries for the sake of expediency, eventually leading to that spaghetti code, big ball of mud legacy application that everyone knows and loves!
(Of course, getting those modular boundaries right in the first place can be a challenge in itself, and even if gotten right, could be subject to change as reality progresses, but I like Evans' point nonethless)

[rajkatie]

Very well said Sam. we should not worry about the size, but focus on what it do.

 " For example, the water pump in my car provides a critical service to my car, and that pump is only 8 inches long. where the water pump that the local water company uses to push water to my town provides the town with a very valuable service, but it is 8 feet long.

The existence of a larger pump does not suddenly transform the pump in my car into a micro-pump: It is still just a pump. Services are services regardless of their size." - Juval Löwy

" There are no micro-services—only services." - IDesign Inc.