Overview
This is a memo about trying prefix.cc for resolving prefixes in RDF data.
Namespace Lookup API
This is a service that allows you to retrieve URIs by providing a prefix.
For example, providing the following:
https://prefix.cc/foaf.file.json
Returns the following result.
Reverse Lookup API
For example, providing the following:
https://prefix.cc/reverse?uri=http://xmlns.com/foaf/0.1/&format=json
Returns the same JSON result as above.
Adding New Entries
The following jps prefix used by Japan Search was not available.
So I tried registering it as a new entry as shown in the screen below.

Afterwards, it could be used like other prefixes.
https://prefix.cc/jps.file.json
It appears that registered entries are evaluated by voting, and you can submit a +/- vote once per day.

References
ex was also registered.
https://prefix.cc/ex.file.json
Summary
We hope this is helpful for prefix resolution.