Remote OK is on of the largest and most popular remote job boards in the world, created by Nomad List founder, Pieter Levels in 2015. They share their site traffic publicly, and get 600-800k visitors per month.
The site's wide reach alone makes it a popular choice for employers hiring remotely. Where the site falls behind, however, is in its complete disregard for user experience and design.
FlexJobs is a flexible and remote job board helping job seekers "have a faster, easier, and safer job search". Founded in 2007 by Sara Sutton (founder of remote.co), they're well-established and possibly the oldest remote-focused job board in the world.
Because they've been around since 2007, they're well-established and have one of the largest remote job databases on the internet, with 20,000+ jobs across 5,000+ companies! However, most of the jobs posted on FlexJobs are also available online for free from other sources — the difference is that FlexJobs aggregates them in one place, which can make it easier for job seekers.
The site is relatively easy-to-use, but is starting to look very outdated and confusing to navigate for both job seekers and employers. For job seekers, the search functionality has some great filters, but the layout of the site is messy and confusing to navigate. It's also not free to use for employers or job seekers (we'll get into that).