What we look for

How is source code setup?

is there an SCMS? Which one?
how do the commit messages look?

In source code:

how is the JSON documented?
are there tests?
what were the decisions on the datastore and why?

Response structure:

is response in JSON or something else?
is the timestamp included in the actual response?
is the response to all the currencies vs. single currency consistent?
are all the responses consistently designed?