There is no simple, likely way to swap underused possessions for other goods and services. Millions around the world barter their belongings on social media (we've counted more than 3 million online barter groups members in Argentina, Chile and Venezuela alone), facing a lot of pains trying to complete transactions, like scams and long negotiations. Overall, they are limited by the natural barrier of barter systems: every deal requires reciprocity between two, which is inefficient on a large scale. Swapig is a trading platform that improves people’s chances to swap what they have for something they want. Users publish a photo of what they offer, then search and pick what they want in exchange without previous negotiations. Our algorithm not only finds reciprocal offers for 1-on-1 trades, but also multi-reciprocal offers for circular trades between three ( A ->B, B-> C, C -> A) or more users. For a fee, users will know in real time every deal available to them, without having to search items and wait for matches.