I built AlertChecker to help address a limitation with AI chatbots - they only respond when you've asked them something. You talk to them and they talk back. I wanted a way for them to tell you something of interest another time, when you're not even in a conversation.

For example, type a statement like "the iPhone 16 Pro is back in stock at apple.com" or "it's going to rain in London tomorrow," and AlertChecker uses AI models with live web search to monitor it periodically. You'll then be emailed when it becomes true. No scraping rules to configure, no specific site integrations to pick, just a sentence in plain English.

It's a Next.js web app with a small Node backend service doing the actual checking in a continuous loop. There's also an MCP server, so if you use Claude or ChatGPT you can create alerts by just asking in a normal conversation instead of opening the site.

The number of checks is currently limited overall while I keep an eye on costs, so it's shared across everyone using it right now rather than a fixed per-account quota. I'll be raising that as I get a better sense of real usage patterns.

Seems like this tool could have a very wide range of applications (given the statement can be literally anything under 4000 characters). Interested to hear about real-world uses beyond stock/price checking or weather alerts.