What is faresnipe?

Faresnipe is an open source tool that watches for mistake fares, airline pricing errors that offer flights far cheaper than normal before the airline notices and fixes them. These deals tend to disappear within minutes, and paid services already exist that charge an annual fee to alert you to them. Faresnipe is presented as the free, open alternative that runs entirely on your own machine, keeps your data local, and has code short enough and simple enough that you can read and understand all of it yourself. After installing it, you set up which airport you are flying from and which destinations you care about, then start it running. There is no API key to obtain and no account to create. Once running, it repeatedly checks flight prices, compares each new price against the typical historical price for that same route, and flags anything that looks unusually cheap according to a set of rules, some of which can escalate a fare from an ordinary deal into a flagged mistake fare if it is especially far below normal. Under the hood it works in three parts. A scanner reads your configured routes and asks a flight pricing source for a quote. A detector compares each new quote against the historical typical price stored locally and decides whether it counts as a deal or a mistake fare. Everything is saved in a simple local database file, which also powers a small dashboard and a web API you can check prices through yourself. If you want to be notified automatically rather than checking manually, it can send alerts through a Telegram bot or a custom webhook. The dashboard is deliberately simple, built with plain HTML, CSS, and a small amount of JavaScript rather than a full frontend framework, keeping the whole project lightweight and easy to install.