Poshmark is a social commerce marketplace where users in the US, Canada, and Australia can buy and sell new or used clothing, shoes, and accessories. The company is headquartered in Redwood City, California. 

The rapid purchase-to-discard ratio of fast fashion and piling up of clothing in landfills, often made from synthetic materials which do not decompose easily. When consumers throw away clothing in the garbage, not only does it waste money and resources, but it can take 200+ years for the materials to decompose in a landfill. During the decomposition process, textiles generate greenhouse methane gas and leach toxic chemicals and dyes into the groundwater and our soil. There is also the unmet potential of clothing which could be resold, and its lifetime extended- as opposed to manufacturing new clothing which requires more energy and water use, and is associated with more carbon emissions. Finally, there are lack of incentives for people to responsibly pass on/resell their unwanted clothing due to the associated costs- be that time or monetary (e.g. shipping).

Poshmark addresses these problems through providing an easy way to redirect unwanted clothing and thus divert it from landfills. It also provides a second-hand marketplace thus encouraging buying second hand and diverting ‘new new’ purchases, thus hopefully slowing down resource depletion.