Several successful startups initially outsourced the development of their products to external developers or agencies before building large in-house technology teams. **Slack**, for example, worked with an external design and development team during its early product development. **WhatsApp** also relied on outsourced development resources in its early stages while focusing internally on building and improving the product. **Skype** used external development expertise during parts of its initial development. Outsourcing can help startups access specialized technical skills, reduce initial development costs, speed up product launches, and allow founders to focus on business strategy and customer needs. As startups grow, many gradually bring development capabilities in-house.