Technical Breadth
Many capabilities for one customer
A product engineer builds one capability for many customers. An FDE builds many capabilities for one. That inversion is the whole job, and it asks for range across the stack plus the judgement to reach for a script when a service would be showing off. Depth still matters. Breadth is what makes the role possible at all.
Progression
What changes at each level.
- FDE I
Deployed
Productive in one primary language and comfortable reading a second. Can build a working integration against a documented API, query and shape data, and put a usable interface in front of it with review.
- FDE II
Embedded
Works across the stack without hand-off: ingestion, transformation, service layer, and interface. Picks up an unfamiliar customer system, including a poorly documented legacy one, and is contributing within days. Distinguishes the part that must be durable from the part that is scaffolding, and builds accordingly.
- FDE III
Trusted
Designs the technical shape of a whole deployment: data model, boundaries, integration surface, failure behaviour. Makes defensible build-versus-configure calls under time pressure and can justify them to both the customer's architects and their own engineering team. Deliberately leaves some things unbuilt.
- FDE IV
Principal
Establishes the reference architecture that other deployments start from. Recognises when a class of customer problem has been solved enough times by hand that it belongs in the product, and makes that case with evidence from the field. Sets the technical bar the rest of the team is measured against.