How to Write a Recommendation Letter (For a Coworker)
You worked with them, but you weren't their manager. Here's how to write a letter that's specific, credible, and actually helps.
A coworker asked you for a recommendation letter. You worked with them — but you weren't their manager. You're not sure exactly what to say, since the standard format assumes a hierarchical relationship you don't have. You don't want to write something generic, but you also don't want to overstate the closeness of your collaboration. Coworker recommendations are a real category and they have their own conventions.
Below are five things to know about writing a strong coworker recommendation — what to say, what to avoid, and how to be genuinely useful when you're describing someone you worked alongside rather than under.
Lead with the working relationship, not your title
Don't try to sound like a manager — you weren't one. Open with the actual relationship: "I worked alongside David on the [team/project] for two years as a fellow [role]." The reader will read peer-to-peer recommendations differently than supervisor recommendations, and that's fine. Your perspective has its own value: you saw them in collaboration, not in evaluation, and that view is sometimes more useful for the role they're applying to.
Focus on what you saw them do up close
As a coworker, you have access to behaviors that managers don't see — how they handle disagreement with peers, how they help when someone's stuck, how they communicate in real time on the messy parts of work. Pick the things you actually observed at this resolution. "When the data pipeline broke, he was the one who'd stay late to dig in" or "In our standup, she always asked the question nobody else wanted to ask." These details are credible from a peer in a way they wouldn't be from a manager looking down.
Compare them against your peer set, not your direct reports
If you're going to calibrate, calibrate against people at their level. "Among the engineers I've worked with at [Company] in the last five years, she's one I'd most want on my team." Not "top performer" — that's manager-language, and you can't credibly say it. Peer-comparison framing lands honestly: you're saying who you'd want to work with again, not who you'd hire. The reader can use both kinds of information; they just need to know which they're getting.
Stay in your lane on what you don't know
There are things you can't speak to as a coworker — their leadership ability if they weren't leading, their judgment under pressure if you didn't see it, their growth over time if you only worked together briefly. Don't fake those. "I didn't manage David, so I can't speak directly to how he handles direct reports, but in our peer collaboration he was consistently the one who..." Acknowledging the limits of your view makes everything else you say more credible. Letters that overreach lose authority; letters that stay in their lane gain it.
Close with a specific endorsement, not a generic one
End with what you'd specifically endorse them for. "I'd hire him onto a team I was leading, and I'd actively look for him at any future company I joined." "If I had a peer slot to fill, she'd be the first call." Specifics from a coworker are more valuable than vague enthusiasm because the reader knows the source has skin in the game — you're vouching for a future working relationship, not just a past one. That's what makes a peer recommendation hit.
A coworker letter that actually helps them
Ghost Writer takes the projects you worked on together, what you saw them do, and the role they're applying for and produces a peer-perspective letter that lands with credibility.