The advantage of one person is coherence: the same mind designs the data, the interface and the infrastructure, with no handoffs and little coordination overhead. The disadvantage is the same thing seen from the other side: everything depends on one person.
Where a solo developer works well
- The product is a web application, a mobile app, an integration or an internal tool of moderate size.
- You want to talk directly to whoever decides the technical details.
- Speed of decision matters more than parallel workstreams.
- The budget does not cover a team’s overhead.
Where a team is safer
- The system is large enough that several people must build parts at the same time.
- You need specialists such as a security engineer, a data scientist and a dedicated designer on the same project.
- The product must be available around the clock with staff to respond.
- Your organisation requires redundancy of people for risk reasons.
The honest limits of one person
Illness, holidays and workload affect a solo developer’s availability, and a single person has limits in range. These are manageable if you plan for them: clear documentation, code and accounts you own, and agreed expectations about response times. A good solo developer will tell you when a project needs more people than one.