You can find they are both similar because both of them cause co founder ripple claims a decentralized network is necessary for a cryptocurrency to be successful in the long term. This is why he split off from Ripple to form Stellar in 2014
Stellar is actively working on awesome partnerships with live impact like IBM, but don’t have as much of a marketing and PR machine behind them. They’re also focused less on big brand banks and more dedicated to smaller money transfer operators. Ripple, on the other hand, has a huge team, lots of capital, and is generating a lot of publicity with big name partnerships.
So the conclusion is Stellar and Ripple serve different markets and offer different technology.