Pick one you had a good relationship with. Call them up and talk to them, tell them you want a reference, and tell them what you've done since you worked for them.
That's what everybody else is doing...
- An intern who I managed.
- A current co-worker who I've collaborated closely with on a number of projects.
- Our current team lead who I regularly collaborate with on architecture design, but I don't report to him.
These people already know that I'm looking for a new position and they've agreed to provide me with a reference. They should be able to confirm any projects and contributions at my current job, where I've been for 4+ years, as well as speak highly about my performance. Is this set of references good enough for a mid-level SDE position or should I look further back into my job history to add an actual manager [1]?
[1] I know I said I wanted senior SDE earlier but I realized I'm better suited for mid-level right now.
By "true" job, I meant to imply I've had short-term jobs, like SDE internships, during college. I suppose I could use references from those positions. However, I wouldn't want to as they were quite a while back and my personality and skillset and responsibility has grown substantially since then.
Anyways, my main concern was not including any sort of manager in my pool of references. Ideally, I'd just want to use current peers. They know me well and have a lot to say. I'm afraid anyone 5+ years back whom I only worked for 3 months would barely remember me.