It should just have basic operations: get, set, and delete.
It should support basic auth over http. If it has a "freemium" model that is okay too.
Does this exist? If not, would you be interested in it?
Stord.io is a key/value store. This is often modelled as a hashmap or a dictionary in programming languages.
Under the hood, stord.io is powered by Redis, with a thin python application wrapper, based on Flask. Stord.io doesn’t assume anything about your data, make whatever nested schema you want!
Full disclosure: if this wasn't already clear, it's my project. I would LOVE feedback/feature suggestions.
I think it would be safe to assume there are also collision problems in unauthenticated ones as well...
What are the key/value durability requirements? (OK to drop values now and then, or does it need to keep them until the end of time?). Need backups? Do values expire, or do you have to expire them manually? Since you can't enumerate or search, how do you delete things? Allowed sizes of keys and values, between bytes and terabytes? How far should it scale? Shared namespace, or namespace per user? Do you need a latency guarantee? How low? Are you gonna use it for something important and need an SLA on the availability of the service as a whole?
A couple of "nearby" points in the solution space:
Amazon S3 is a KV store where the keys look like filenames and the values look like files. High durability, good scaling, pretty high latency. You could also obviously paper a KV store on top of ElastiCache or DynamoDB, which are going to have different properties.
Going low-level and implementing your own in say, golang would probably be the most fun though :p
Hard to say if we could use a SAAS KV store at work without a lot more technical detail on the solution. I'm having a hard time thinking of an app where you'd want a KV store, but not need a database or NoSQL store which you could use instead.