LOR Sample for MS in Computer Science

LOR Sample for MS in Computer Science

A letter for an MS in Computer Science needs one technical decision the writer watched the applicant make. Carnegie Mellon asks for three letters and warns that character references "will not provide good support". Toronto wants at least two letters on independent research. UIUC's professional MCS asks for none.

A list of programming languages and the word "hardworking" do not answer what these departments ask. They ask about the quality of previous work and about research ability. Below are two constructed samples, written by us, for two writers our course-professor sample does not cover: a software engineering manager and a guide whose student worked in a team. If you are the writer, your recommendation letter can get a free Quick Review before you upload it.

Every department page quoted below was checked on October 31, 2026. CMU and Toronto give Fall 2027 deadlines on their pages; UIUC states no cycle. For the letter's layout and a course-professor sample, see our LOR format and sample for MS and PhD recommenders.

What CS departments ask recommenders

Three things in this table change what you do:

1. Course-based and research master's differ. UIUC asks for no letters for its professional MCS and three for its thesis MS. Check which degree you are applying to before you ask anyone.
2. Employers count at CMU, with a condition. CMU says: "Employers are sometimes appropriate, but letters that are simply character references will not provide good support for your application."
3. Toronto refuses free email. "Gmail addresses are not acceptable." Confirm your manager's work address. Our page on Canadian graduate reference letters has the other Toronto rules.

Our view: for an MS CS applicant with two or more years of work, one letter from an engineering manager who reviewed your code is stronger than a third letter from a professor who taught you in a class of 120. The countercase: for Toronto's MSc or UIUC's thesis MS, where letters must speak to research, a manager letter only helps if it describes work that looks like research: a question, a test and a result. If it cannot, choose an academic.

Sample 1: software engineering manager

Constructed example, written by us, not a real letter or a real applicant. Context (invented): the applicant has worked for two years at a payments company in Pune and is applying for an MS in Computer Science. The letter is 303 words.

I am an Engineering Manager at [Company], where I lead a team of nine engineers who build the transaction-routing service. Rahul Desai joined my team in July 2024 after his B.Tech. I have reviewed his code every week since, and I wrote his last two performance reviews.

In March 2025 our service started dropping about one request in ten thousand during peak hours. Three senior engineers looked at it and blamed the network. Rahul did not accept that. He wrote a replay tool that fed one hour of recorded traffic into a test cluster, reproduced the failure, and traced it to a race condition in our connection pool. His fix was eleven lines. His design note explained why the bug only appeared above a certain load, with graphs from his replay runs. I now ask every new engineer to read that note.

In code review, Rahul asks the question before he writes the code. When we planned a new retry policy, he proposed measuring the effect on a copy of production traffic before we changed anything. That experiment showed that our first design would have doubled load on a partner bank's servers. We changed the design.

I have managed 23 engineers in five years. Rahul is one of the two I would trust to investigate a production failure alone. He is weaker at estimating how long work will take; he improved after I asked him to write down his estimates and compare them with the result each sprint.

Rahul wants to study distributed systems formally. From what I have seen, he already works the way a graduate student must: he forms a hypothesis, builds a test, and changes his mind when the data says so.

I recommend him without reservation for your MS in Computer Science.

[Name], Engineering Manager, [Company] · [work email]

Why this manager letter works

• The basis is stated first: weekly code review for two years and two performance reviews. Every claim stays inside what the manager saw.
• One incident carries the letter. The race condition shows a hypothesis, a test and a result. That is the closest a manager can get to the "independent research" CMU and Toronto ask about.
• The comparison names a group: "23 engineers in five years".
• One honest weakness, with what changed. It makes the praise easier to believe.
• No list of languages or frameworks. The CV already has that.

Sample 2: final-year project guide, team project

When the final-year project was a team project, a guide who writes "the team built" tells the reader nothing about the applicant. This sample shows how to separate one student's work from the group's.

Constructed example, written by us, not a real letter or a real applicant. Context (invented): a professor who guided a four-student final-year project. This excerpt is the project paragraph only; the revised version is 141 words.

Weak: Sneha was part of a team of four that built an excellent bus-tracking app for our campus. She worked very hard and was a great team player.

Revised: Sneha Kulkarni's team of four built a live bus-tracking app for our campus. I met the team weekly for nine months and read each member's logbook. The synchronization server was Sneha's work. In the fourth month, buses began to appear twice on the map whenever a driver's phone lost signal and reconnected. Two teammates proposed dropping offline mode. Sneha instead read two published papers on replicated data, chose the simpler of the two designs, and adapted it to our location records. She then wrote a test that cut the network at random points during a simulated route and ran it every night until the duplicates stopped. Her section of the final report was the only one I did not have to return for revision. Of about 60 project students I have guided, she is in the top five for independent judgment.

Why the team-project paragraph works

• "The synchronization server was Sneha's work" answers the question every reader of a team project has.
• The incident is a research act: she read the literature, adapted a published design to a new setting, and built a test for the exact failure. That is what UIUC means by "research abilities and potential", and it is the "independent research" CMU and Toronto ask about.
• It is a systems problem, not a data problem. A CS reader can see the student reason about failure under unreliable networks, which a course grade does not show.

Evidence a CS letter can point to

• A bug, an outage or a wrong result the applicant explained. Say what they tested, not only what they fixed.
• A design review or code review. Quote the decision, not the praise.
• A repository, benchmark or report the reader can find. Name it; do not paste code.
• Teaching or mentoring: a teaching assistant who wrote a test suite, an engineer who onboarded new hires.

Do not claim what you did not see. A manager cannot judge exam performance, and a course professor cannot judge production work. Our guide on employer letters of recommendation for grad school covers the mix of academic and work letters.

Before you upload the letter

1. Check the degree type. UIUC's MCS takes no letters; thesis and research programs want research evidence.
2. State how you know the applicant, for how long, and in what setting.
3. Build the letter on one or two incidents with the applicant's own action visible.
4. Name your comparison group with a number.
5. Use your work or institutional email. Toronto refuses Gmail.
6. Save as PDF. Toronto accepts "Only Adobe PDF format".

Questions about MS CS recommendation letters

Can a manager write an LOR for MS in Computer Science?

Yes, at CMU, which lists "recent employers", and at UIUC, which allows "non-academic references" after time away. At Toronto, letters should speak to research, so a manager letter must describe research-like work.

How long should an LOR for MS CS be?

None of the three departments sets a length. Our page on how long a letter of recommendation should be covers the norms.

Should the LOR mention the applicant's programming languages?

Only inside an incident. A language name with no task attached adds nothing the CV does not already show. Your own UK MSc computer science personal statement should name the same modules your referee mentions.

Not sure who should write it? See LOR from HoD or professor: which is better.

For an analytics rather than CS master's, see the MSBA recommendation letter sample.

Get a free review of the letter

Get a free Quick Review of your recommendation letter against GradPilot's graduate recommendation letter rubric for MS and PhD applicants. It reads for how you know the candidate, incidents rather than adjectives, comparisons that name their group, the case for graduate potential, and the strength of your endorsement. If you are writing from a university outside the US for a reader who may not know your grading system, also try the international academic recommendation rubric.

For hardware or ECE applicants, the LOR samples for MS mechanical and electrical engineering give two constructed letters.

Writing for an applied data science master's instead? The LOR sample for MS in Data Science covers the caught-data-error paragraph those programs reward.

GradPilot's letter reviews aren't for a letter you drafted for a recommender to submit as their own.

More computer science guides:

• Computer science SOP examples for MS and PhD: the applicant's statement for the same programs.
• Can industry letters support a CS PhD?: the same question one degree up.
• PhD recommendation letter sample from a supervisor: a full thesis-supervisor letter.

Hub: graduate school essays.

Sources

Retrieved October 31, 2026, except where noted.

• Carnegie Mellon University School of Computer Science, Graduate admissions (deadlines for Fall 2027 entry: December 9, 2026): three letters, up to five, faculty or recent employers, independent research, character references.
• University of Illinois Urbana-Champaign, Siebel School of Computing and Data Science, Applications process and requirements (no cycle stated): three letters for MS thesis and PhD, research abilities, non-academic substitutes, no letters for MCS.
• University of Toronto Department of Computer Science, How to apply (Fall 2027; deadline December 1, 2026): three referees, two on independent research, no Gmail, PDF only.