Hiring in-house gives you long-term retention of knowledge. The people learn your domain over time, and software development company this context remains with you. The catch is time and rigidity: filling a senior role takes months, getting someone productive adds several more weeks, and the payroll continues whether the roadmap is full or empty.
Project outsourcing means someone else is accountable for shipping: the partner staffs the project, they manage the day-to-day work, and the provider carries the risk of missing the date. The model works when the scope is reasonably clear and your side has an available product owner. It breaks down when nobody on your side owns the product, because an external team will not invent your business rules.
Staff augmentation is the middle option: you add engineers while keeping responsibility for delivery yourself. It moves quickly — a suitable engineer can start far sooner than a new hire vue js programmer — and the commitment ends when the work does. The catch remains that your technical leaders have to have the capacity to direct the work. Without that, you end up paying hourly for uncoordinated work.
Most of the time, these models are combined. One durable pattern puts the architecture and the core domain in-house, while an external team covers peaks, well-defined modules or performance php vs python platform work. The rule is easy to state: retain what defines your product, and outsource the well-trodden work.
A few questions resolve most of these debates. First: is this nearshore software development the product itself, or a supporting tool? Second: over what horizon will you need this capacity — a quarter or a decade? Third: who owns it once the vendor leaves? Work through them with real answers and the appropriate option usually chooses itself.