I built <a href="http://jsonblob.com" rel="nofollow">http://jsonblob.com</a> for this purpose. It has an HTTP API as well as we nice GUI interface to edit your JSON. It's open sourced and really just a thin webapp on top of mongo, so it's easy to run your own.
Could be used for notepad API or something public. That said, it seems that services like Parse and Firebox seem more robust and also have faster response times.
I can't see the use case of this. If it was editable after saving then that would make sense, but this is just static. And being static, you're better off just bundling it with the app. Unless I'm missing something?<p>Nice presentation though, the site looks nice.<p>EDIT: I see you can create and update through the HTTP API, which makes it much more useful.
Why not use <a href="https://www.firebase.com" rel="nofollow">https://www.firebase.com</a>? Seems more reliable (Privacy Policy, ToS, SLA) and easier to start using, and it has a free tier if you need something quick for development.
I built a similar thing, in Go on App Engine: <a href="https://github.com/imjasonh/simply-put" rel="nofollow">https://github.com/imjasonh/simply-put</a>
for anyone interested in a an easy tool for building JSON store/APIs, you might find HiveMind (crudzilla.com) useful, I am the developer.<p>Here's a simple screencast:
<a href="http://crudzilla.com/assets/img/info-graphics/instantiator.gif" rel="nofollow">http://crudzilla.com/assets/img/info-graphics/instantiator.g...</a><p>There's a lot that you can with it, in terms of generating JSON.