<div></div>

div {
  background: #2db34a;
  border-radius: 50%;
  height: 50px;
  position: absolute;
  width: 50px;

  animation: pulse 1s ease infinite;

}

@keyframes pulse {
  0% {
    transform: scale(1);
  }

  50% {
    transform: scale(1.1);
  }

  100% {
    transform: scale(1);
  }
}