Building your own team gives you the deepest product knowledge. The engineers absorb the business domain over months and years, and this context sits in the building. The price is time and rigidity: recruiting a strong engineer is slow, ramping up adds more time, and bespoke software development company the cost continues through the quiet quarters.
Handing a project to a vendor project-based development is the arrangement where the vendor owns delivery: the provider staffs the team, the provider manages the day-to-day work, and the provider carries the delivery risk. The model works when the outcome can be described and you have someone who can make decisions quickly. It breaks down when there is no one to answer questions, since a vendor will not guess what the business wants.
Team extension is the middle option: you rent capacity and keep responsibility for delivery yourself. It is fast — a matching profile can start almost immediately — and the commitment ends when the work does. The catch is that your engineering managers need time for code review and planning. If that capacity is missing, you end up paying hourly for uncoordinated work.
In practice, dedicated team vs freelancer these models are combined. A frequent arrangement holds architecture, product decisions and core domain code in-house, while an external team handles the parts that are bounded and specifiable. The rule is simple enough: keep what differentiates you, and outsource anything a competent team can specify and deliver.
Three questions usually settle it. To begin with: is what you are building central to how you make money, or a supporting tool? Next: over what horizon does the work continue — one project or a permanent roadmap? Finally: who will maintain it in two years? Work through them with real answers and the model is normally clear.