I built something almost identical in 2011. It really doesn't have as much utility in practice as you think initially. CSS selectors are an interesting idea for extracting data from pages, but it's extremely fragile. You have to either parse the page's raw html using something like jsdom, or you run it through a headless browser like Phantom. In the first case, it completely fails for any modern SPA (angular, react, etc). In the second case, phantom is painfully slow and difficult to interact with, and often doesn't run/render an SPA as a regular browser does.
You can write tests around whether your selectors are returning data, but even simple refactors from a dev team quickly break your selector profiles multiple times a week or month.
kimono labs used to do something similar, but shut down recently. They had a nice clicky pointy interface that allowed you to build the selectors by clicking on elements, with an immediate preview. They also handled things like pagination etc.
> I'm really surprised nothing like this has existed before
But how would you monetize it?
Unlike an RSS feed, you really don't know how the JSON response would be used, so you can't inject ads into it.
And if you charge for it, wouldn't people assume it would continue to work, but site "scrapers", regardless of how they are configured, are likely to break, so it would be tougher having customers pay for something that could break at any time leaving them having to figure out if its the service that's changed/broken or the page that's changed.
Don't get me wrong- some great businesses have been/are based on "scraping" in one way or another. However, as cool as this is, it's just another way to "scrape". If the person hosting the page would provide an API or JSON view instead, you'd be loads better off.
Freemium, professional support, expanding it into an abstraction layer above the APIs for multiple services, selling a version that larger companies can run on their own servers which they might need for data security...
>However, as cool as this is, it's just another way to "scrape"
Isn't that the point? The demo seems like it'd be a lot easier, less verbose, and probably less brittle, than using cUrl/xpaths or otherwise parsing that HTML yourself.
We launched WrapAPI (https://wrapapi.com/) a few weeks ago with the same functionality, but a bit more complex and powerful process to get set up. You can not only specify CSS selectors yourself but define them point and click.
The barrier for starting with JamAPI is impressively low, though! Kudos on the developer-friendly user interface.
Running this sort of thing as a service/api never panned out for us because you are almost universally robots.txt denied and/or blocked.
We briefly tried, and supported a wiki of json extraction scripts at parselets.org, but it went nowhere after a few months.