I used to use .dev as a domain extension for doing local development using MAMP Pro, but I have had to switch to using .local instead because Safari and Chrome both now force any domain ending in .dev to load over HTTPS which I’m not running for my local development environments.
Google made this decision (and Apple is following their lead) because Google bought the rights to provide .dev as a publicly available TLD and will be putting them on sale in May of this year. For now the browser-side enforcement of the HTTPS-only policy is inconvenient, but it means making a change that I would need to make regardless to avoid potential collisions in the future.
This is a new enough situation that I still have old projects for which I haven’t changed the settings. When I try to load them, I get the message that the server is unavailable even though I’m looking at MAMP Pro chugging away right in front of me. This happens sufficiently infrequently that it still takes me about five or ten minutes of confusion to remember the cause and change over to a .local domain.
As usual, the hope is that writing up a short note will mean I remember what’s going on next time.