A warranty is a written guarantee that something will meet certain expectations or standards for a set period of time, and sets out what remedies are available if such expectations or standards are not met.
Many different types of products can have a warranty, from ecommerce store products to mobile apps to websites created by web development firms.
Warranties must grant at least the minimum protection required by law, but then can either limit their warranties drastically, or be generous and cover a range of potential issues and for a long period of time. In some cases, a warranty can be an "as is" statement and no guarantee or remedy will be given.