Complete swiper example + run the swiper when it enters the viewport - treshold = "percent of element visible" -> 0.1 = 10%

swiper-play-in-viewport.js

// TESTIMONIALS SWIPER
  const testimonySwiper = new Swiper(".testimonySwiper", {
      loop: true,
      slidesPerView: 1.3,
      spaceBetween: 16,
      centeredSlides: true,
      initialSlide: 3,
      autoplay: {
          delay: 7500,
          disableOnInteraction: true,
      },
      breakpoints: {
          // when window width is >= 480px
          440: {
              slidesPerView: 1.4,
              spaceBetween: 16
          },
          // when window width is >= 640px
          960: {
              slidesPerView: 4,
              spaceBetween: 16
          },
          1250: {
              slidesPerView: 4,
              spaceBetween: 16
          },
          1440: {
              slidesPerView: 3.6,
              spaceBetween: 32.
          },
          2560: {
              slidesPerView: 5.5,
              spaceBetween: 32.
          }
      }
  });


  // run testimony swiper when it enters the viewport
  const ttSlider = document.querySelector(".testimonySwiper");
  const observer = new window.IntersectionObserver(([entry]) => {
      if (entry.isIntersecting) {
          testimonySwiper.slideNext();
      }
      // console.log("LEAVE")
  }, {
      root: null,
      threshold: 0.1, // set offset 0.1 means trigger if atleast 10% of element in viewport
  })