I use a bot for booking overnight huts on the more popular hiking trails in my country. They become available for booking online at a fixed time each year and are all taken a few seconds later. Using a bot is the only reliable way to get one.
Amusingly there are news articles every year about whether or not people are using bots to book these huts and the operators always deny it vehemently. Whereas I know my bot is up against loads of other bots.
We used to run into the same issue booking camping spots in Massachusetts, which open many months in advance. I don't know what the situation is nowadays but it used to be very competitive, with spots vanishing in seconds after opening.
Amusingly, one camper family we came across said they manually register at the stroke of midnight, but they all do it together from like 6 computers in their house.
For mine, I just used a $1/mo VPS with a cron job running a bash script that used curl to poll the parking system and determine if its response was interesting. I used "copy as cURL" from browser dev tools to find something usable (which incorporated a slightly fragile, but very long lived, session token corresponding to my "cart") and I actually had to use curl-impersonate [0] for Cloudflare bot detection to stay out of my way. And then curl to alert me via Pushover.
Amusingly there are news articles every year about whether or not people are using bots to book these huts and the operators always deny it vehemently. Whereas I know my bot is up against loads of other bots.