Main point: The MVP engineer is a part of the initial team who scopes out a product, builds the first iteration of the product to verify its "raison d'etre".
A minimum viable product is a minimal implementation of an idea. An implementation that can verify the value-add of the idea. This first implementation should be cost effective while implementing the core features and functionality required to decide whether to continue on developing the product or to reject the hypothesis.
The MVP engineer is one of the core people on the team making this happen. This person undertakes the technical responsibility for this phase in the product cycle.
Before the MVP engineer comes almost nothing. The only thing that precedes the MVP engineer is the decision that a product should be made and some vague ideas on what kind of value the product should provide. The MVP engineer will assist in scoping initial versions and build them to validate the business potential.
The MVP engineer is an expert in this initial phase of a product life cycle.
Technically, the MVP engineer is a one-stop-shop and does what it takes to build the product: Application development, continuous integration, external integrations, machine learning, smart contract development, etc. The person possesses all competences required to build this initial product that showcases viability.
Consequently, this also means not attending to a lot of other concerns. What concerns these are are unique to the project. An example is scaling concerns that are deferred to the point where the product scale is eminent.
Another one is the architectural elegance, or architectural clarity. The point is, that MVPs tend to pivot heavily in the initial phases. Investing in the architecture at this points risks imposing the sunk cost fallacy – Nobody likes to throw out a big investment.
The MVP engineer makes it easy to kill your darlings and retains the project scope at a level where this is easy.
Should the project reach a validation point where further development is needed then the MVP engineer takes the project into the next phase. This is important as knowledge needs to be handed over and a team culture needs to be built around the mission. Hence, the MVP engineer will do recruiting and engineering interviews, and hire for the new technical roles. The engineer will also disseminate knowledge about the tech stack and the project to new participants to ensure the productivity of the team.
The last thing the MVP engineer does is scoping further development not to leave the product in a vacuum and also recognizing the elements that were previously not attended to, but are important to ensure the success of the product.