In late January 2014, Klein and Matthews announced that they, along with Matthew Yglesias and Melissa Bell, would be starting a new online media venture with Vox Media. The venture, named Vox.com, launched in early April 2014, and Matthews wrote his first article for the site in April 2014.
Matthews has also written for Salon and The New Republic and has appeared on Bloggingheads.tv. His writings have covered basic income, immigration policy, effective altruism, among other topics.
Matthews was listed as one of “five rising stars under 25” in Politics Daily by Katie Glueck in 2010. Matthews is noted for his use of data visualizations in his publications. Charity evaluator and effective altruism advocate GiveWell published a conversation with Matthews from when he was still working for the Washington Post Wonkblog section. In 2016, the Autistic Self Advocacy Network recognized Matthews as the most outstanding Autistic journalist of the year by presenting him with the Harriet McBryde Johnson Award for Non-Fiction Writing.