Leap Second VS Iframely

• Keeps civil time aligned with Earth's rotation
  Leap seconds keep UTC within 0.9 seconds of UT1, which is based on Earth's actual rotation. Clock time therefore stays tied to the position of the Sun and does not drift away from the solar day.
• Supports astronomy and celestial navigation
  Telescope pointing, satellite tracking and some legacy navigation systems assume UTC is close to UT1. Leap seconds avoid the need for separate corrections in those systems.
• Small, frequent adjustments instead of big jumps
  Adding single seconds when needed avoids a much larger correction later, such as a leap minute or leap hour, which would be more disruptive and harder to explain to the public.
• Internationally standardized process
  The IERS decides on leap seconds and announces them about six months ahead. This gives a single authoritative, globally coordinated mechanism that timekeeping systems can follow.

Possible disadvantages

• Causes software and infrastructure failures
  A 23:59:60 timestamp breaks assumptions in many systems, such as monotonic time and 60-second minutes. Past leap seconds have caused crashes, hangs and outages in operating systems, databases and cloud services.
• Unpredictable schedule
  Earth's rotation speed varies irregularly, so leap seconds cannot be predicted far in advance. Systems that need long-term time calculations cannot know future UTC offsets, so they need frequent updates.
• Inconsistent handling across systems
  Some systems step the clock, some repeat a second, and others smear the extra second over hours, as Google and AWS do. These differences can leave clocks briefly disagreeing, which hurts distributed systems, logging and financial timestamping.
• Being phased out
  In 2022 the CGPM voted to stop using leap seconds by or before 2035. Anything built around them has an uncertain long-term future, and the planned replacement will let UTC drift from solar time.
• Website details unverified
  I can't access https://www.leapsecond.co, so these points describe leap seconds as a concept, not that site's specific product or service. Check the site directly for its features, pricing and quality.

• “No code”
  Instead of API calls, an option to use our HTML template and some JavaScript spice.
• JSON
  Only two endpoints to choose from and connect: complete Iframely data or a simple oEmbed connector. Both have the html field for you to embed.
• Cards and URLs previews
  Engage your users with URL preview cards, just like they expect in a modern app. Change cards design easily in your settings.
• React and JavaScript
  React, and other JavaScript runtimes won’t let you run third-party scripts. Iframely fixes this by hosting media in an iFrame instead.
• Responsive embed codes
  Rich media will resize and fit your site’s design on any device, with a correct aspect ratio or a horizontal height.