Under the hood
The simple loop behind AlertChecker: interpret a plain-English condition, check current public information, evaluate it, and notify you when true.
You don't need to understand the machinery to create an alert, just as you don't need to understand an engine to drive a car. But it can be helpful to know what happens after you submit your statement.
The condition is the starting point
An alert begins with a factual statement rather than a collection of technical rules. “The iPhone 16 Pro is back in stock at apple.com” and “It will rain in London tomorrow” describe a condition that can be evaluated as true or false. The more clearly and precisely you describe the relevant product, place, date, or price, the more accurate the checking is.
AlertChecker checks current information
On a schedule, AlertChecker researches the public web for the information needed to evaluate the statement. A supplied webpage is treated as an important source. For sites that load their useful data through an API, a public cURL request can preserve the request method, headers, and body needed to retrieve the current response.
This is why AlertChecker can still work when the answer is not a single line on one predictable page. The relevant evidence may be a product listing, an official notice, current weather information, or another public source that answers the condition.
The result is evaluated, then acted on
The gathered information is evaluated against the statement. If the condition has become true, AlertChecker sends the configured notification. Your alert history records all the checks, so you can review history of how the relevant information and result has evolved.
This evaluation step is the key distinction from a generic page-change monitor. A changed page is only an input; the desired outcome is the signal. It is of course necessary to verify sources before making important consequential decisions.
One simple loop
- You describe the fact that matters.
- AlertChecker periodically checks current public information.
- It evaluates whether the fact is now true.
- It notifies you when the condition is met.