Building your own team buys you the most control. The developers internalise your customers and your data model over months and years, and this context stays with you. The price shows up as slow hiring and fixed overhead: hiring well is slow, ramping up takes several more weeks, and the cost continues whether the roadmap is full or empty.
Project outsourcing means someone else is accountable for shipping: the partner staffs the roles, they manage the day-to-day work, and they absorb the risk of missing the date. The model works when the outcome can be described and there is a decision maker with time for it. It works badly when nobody on your side owns the product, as the provider will not invent your business rules.
Team extension is the middle option: you bring in house vs outsourced development team dedicated developers vs freelancers comparison but keep responsibility for delivery in-house. It is fast — a suitable engineer is often available almost immediately — and the commitment ends when the work does. The trade-off remains that your technical leaders must have the bandwidth to manage them. Without strong internal leadership, you end up paying hourly for uncoordinated work.
Most of the time, companies blend them. One durable pattern keeps architecture, product decisions and core domain code with permanent staff, while a partner covers discrete features, migrations or mobile clients. The principle holds: hold on to the parts that are hard to re-learn, and rapid mvp development contract out the well-trodden work.
A few questions resolve most of these debates. To begin with: is the system the product itself, or a supporting tool? Second: for how long will you need this capacity — one project or a permanent roadmap? Last: real estate platform development company who owns it once the vendor leaves? Answer those honestly and the model becomes obvious.