Perhaps not exactly a company, but the CIA is way too well-known to not be included! The Central Intelligence Agency's choice of web technology has been Gatsby. Their Gatsby site has around 3000 pages in total, according to their sitemap.
Link: CIA.gov
National Geographic uses Gatsby with an impressive amount of pages and articles: around 16,000 according to their sitemap.
Link: NationalGeographic.co.uk
Cloudflare uses Gatsby for their marketing site with around 1450 pages on their main English site. In total, they have 15 different language sites, so if each has that many pages, then they have around 21,750 pages in total.
Link: Cloudflare.com
Riot Games uses Gatsby for their League of Legends, Valorant and TFT websites.
League of Legends: LeagueOfLegends.com
Valorant: PlayValorant.com
Teamfight Tactics: TeamfightTactics.leagueoflegends.com
Airbnb uses Gatsby for their separate Engineering & Data Science website.
Link: Airbnb.io
Calendly uses Gatsby for their marketing site and has around 1100 pages according to their sitemap.
Link: Calendly.com
Ahrefs uses Gatsby for their marketing site.
Link: Ahrefs.com
Little Caesars uses Gatsby for their Pizza pickup and delivery ordering. Here's a quote from them:
Traffic spiked immediately after our Super Bowl ad aired, and we saw a high number of simultaneous uses. I remember watching and seeing we had 3,000 simultaneous users, then 10,000, then a few seconds later it was 15,000 — and we didn’t have to worry. Because we built with Gatsby, we knew we had the performance to handle the traffic without even thinking about it!
Link: LittleCaesars.com
The TypeScript documentation site has been built using Gatsby and has around 900 pages at the moment according to their sitemap. TypeScript is developed and maintained by Microsoft.
Link: TypeScriptLang.org
Linktree's marketing site uses Gatsby.
Link: Linktr.ee
IBM's Carbon Design System uses Gatsby as its foundation for their design system. Here's a quote from them:
Gatsby just works. With the old system, I had to fight with something for a few days to troubleshoot issues. With Gatsby, you install and it just works. It’s stress-free.
Link: CarbonDesignSystem.com
Updated last time on January 21st, 2023. What changed: Added IBM's Carbon Design System, and added some direct quotes from the sites when possible.