A startup or start-up is a company or project begun by an entrepreneur to seek, develop, and validate a scalable business model. While entrepreneurship refers to all new businesses, including self-employment and businesses that never intend to become registered, startups refer to new businesses that intend to grow large beyond the solo founder. Startups face high uncertainty and have high rates of failure, but a minority of them do go on to be successful and influential. Some startups become unicorns: privately held startup companies valued at over US$1 billion.
Startups typically begin by a founder (solo-founder) or co-founders who have a way to solve a problem. The founder of a startup will begin market validation by problem interview, solution interview, and building a minimum viable product (MVP), i.e. a prototype, to develop and validate their business models. The startup process can take a long period of time (by some estimates, three years or longer), and hence sustaining effort is required. Over the long term, sustaining effort is especially challenging because of the high failure rates and uncertain outcomes.