# RxJS vs Promises
In a nutshell, the main differences between the Promise and the Observable are as follows:
- The Promise is eager, whereas the Observable is lazy,
- The Promise is always asynchronous, while the Observable can be either asynchronous or synchronous,
- The Promise can provide a single value, whereas the Observable is a stream of values (from 0 to multiple values),
you can apply RxJS operators to the Observable to get a new tailored stream.
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Why RxJS? RxJS vs Promises