LinkedIn has become the defacto area for working world recommendations. Granted, people are not going to give you recommendations on there without it being a 'strong' recommendation, and you also have to approve it, so you will never see work-related recommendations that are bad. "Standard glowing references".
The people writing recommendations on LinkedIn are also usually colleagues, they don't have to be your boss. From what I have seen, they are also never produced under duress, since these people writing them may hang out with you outside of work.
These letters of rec may not tell you much, but they will at least tell you the type of people that the candidate has worked with in the past. If they are getting other developers to write letters of rec then they probably fit into a team environment well. If they get their managers to do it, then they probably are well-manageable. Etc., etc.