A feature is something that your application or service does. Usually, we don’t give it a lot of thought, but I recently had an interesting discussion about the exact distinctions between a business feature and a technical feature.
Let's imagine that we are talking about an application that allows you to send snail mail. We've already seen it before. A user will call the API and then a few days later a physical letter will show up at your door. So far, it is pretty simple. The question is, what can you offer in addition to expand the business?
For example, we might offer:
- Mail tracking: Providing a way to ensure that the recipient actually got the letter.
- Snail mail to email: Getting a physical email and having that sent to the customer.
Those two are obvious extensions to the core business, and from the point of view of the business, it is great. From a technical perspective, that is a whole lot of complexity. You need to integrate with FedEx to handle the mail tracking, and you need to setup some sort of an automated system that will sort the mail, scan it and upload it to the customer’s account.
The problem is that at this point, you don’t really know what kind of reaction those features are going to have. They are both nontrivial and in some cases require major capital expenditure to implement and are pretty hard to properly size up front.
So, you split it. Instead of doing this as a single feature, you have a business feature and a technical feature. A business feature means that your business offers this service, building that requires research to show that we can actually offer that, check whatever there are legal ramifications (some mail can be sensitive, privacy concerns, etc.), check what kind of pricing we can charge, etc. The technical feature is actually implementing all of that.
The key observation here is that you don’t actually do the technical implementation, at least not just yet. You do the work around the business end of the feature, and then you announce this feature availability. As in, right now you can track the snail mail, or right now you can get your mail scanned and uploaded. This is done with minimal technical work in the backend, and with the caveat that this still experimental and pricing might change.
This isn’t cheating, mind you. Once you announced this feature, you wait to see what kind of reaction we’ll have. One of the options is that users will really love this feature, and start immediately using it. In this case, you have a good problem, people are flocking to give you money. In the meantime, you have Joe and Samantha, from the local high school working for minimum wage in the afternoon to manually do the work. So you can complete the customer expectations, as you are now working to complete the technical side and automate the whole thing (firing Joe and Samantha along the way).
The key here is that you don’t have to do any major upfront investment in development or in facilities before you can have this feature. Most of the time, even if it is a major feature, the ramp up time is enough for you to have a pretty good idea about what you actually need to do. And in the meantime, you have a micro service architecture, it is just that the services aren’t called FedExTrackingService and ScanAndSortPhysicalMailService, but Joe and Samantha.
In other words, you have mechanical Turk the feature until you can teach you system to properly play chess.