The main serif type, used in the site’s masthead, headlines, and body, is EB Garamond (external link). Garamond is one of my favorites, an elegant old-style serif.
The roman is based on type cut by Claude Garamont (c. 1495–1561).11Not all typefaces called Garamond are the work of Garamont; many are based on the types of Jean Jannon (d. 1658). This does not mean the misnamed typefaces are bad! But there’s a century dividing the types of Garamont and Jannon, so it seems worth noting the distinction. As with most modern Garamonds, the italics are Robert Granjon’s (1513–1589). Until the mid 16th century, romans and italics weren’t paired or thought of as a style variant like they are now. They were separate typefaces, and entire books might be set in italic. So while Garamont did cut italics, they were different types.
EB Garamond in particular was developed by Georg Duffner using the Egenolff-Berner specimen, printed in 1592. Octavio Pardo then added the bold faces (which weren’t really a thing until like the 19th century) and reworked the font to support variable weights.
Captions, some editorial text, and the accent punctuation in the masthead and on the front page are set in Inter, by Rasmus Andersson. Inter is a neo-grotesque sans-serif designed for screens, the sort that’s often used in the modern brutalist typographic style.
Fira Code is infamous for its large number of programming ligatures, such as replacing `===` with a single glyph of three horizontal lines.