Stellar is a distributed hybrid blockchain platform that aims to help facilitate cross-asset transfer of value at a fraction of a penny. Stellar is aiming to be an open financial system that gives people of all income levels access to low-cost financial services.
Through the use of its intermediary currency Lumens (XLM), a user can send any currency that they own to anyone else in a different currency.
For instance, if Joe wanted to send USD to Mary using her EUR, an offer is submitted to the distributed exchange selling USD for EUR. This submitted offer forms is known as an order book. The network will use the order book to find the best exchange rate for the transaction in-order to minimize the fee paid by a user.
This multi-currency transaction is possible because of "Anchors". Anchors are trusted entities that hold people’s deposits and can issue credit. In essence, Anchors serves as the bridge between different currencies and the Stellar network.
Lumens are the native asset (digital currency) that exist on the Stellar network that helps to facilitate multi-currency transactions and prevent spams. For multi-currency transactions, XLM is the digital intermediary that allows for such a transaction to occur at a low cost.
In-order to prevent DoS attacks (aka spams) that would inevitably occur on the Stellar network, a small fee of 0.00001 XLM is associated with every transaction that occurs on the network. This fee is small enough so it does not significantly affect the cost of transaction, but large enough so it dissuades bad actors from spamming the network. The collected fee is then redistributed and added to an inflation pool. This inflation pool releases Lumens at a rate of 1% each year.