I believe they are standard IATA airport codes (https://en.wikipedia.org/wiki/IATA_airport_code) but

I believe they are standard IATA airport codes (https://en.wikipedia.org/wiki/IATA_airport_code) but that list posted yesterday (https://speed.cloudflare.com/locations) would be a nice cf-specific endpoint to use, for as long as it's around
An IATA airport code, also known as an IATA location identifier, IATA station code, or simply a location identifier, is a three-letter geocode designating many airports and metropolitan areas around the world, defined by the International Air Transport Association (IATA). The characters prominently displayed on baggage tags attached at airport ...
Was this page helpful?