Back-End Developer cover letter example

This example shows how a Back-End Developer can pair one clear hook with modest, specific evidence about APIs, databases and reliability, without overstating the scope of the work.

Sofia Alvarez

Back-End Developer

Dublin

Hiring Manager

Harbourline Software

October 2026

Subject: Application: Back-End Developer – Sofia Alvarez, Dublin

Dear Hiring Manager,

I am applying for the Back-End Developer role at Harbourline Software. I enjoy building APIs that other teams can use without guesswork, and your focus on dependable, well-documented services is what drew me to this position.

In my current role I integrated third-party payment and messaging APIs in Python and added retry logic and idempotency keys, which helped prevent duplicate transactions. I also documented our endpoints with OpenAPI so front-end colleagues could integrate without waiting on me.

Day to day I work with PostgreSQL, Redis, Docker and AWS. I write SQL migrations for new tables and indexes, and I helped address injection and access-control findings from a security audit. I would bring the same care for clear contracts and safe changes to your team.

Thank you for considering my application. I would welcome a conversation about your services and how I could contribute, and I am happy to share code samples or API documentation I am able to discuss. I look forward to hearing from you.

Kind regards, Sofia Alvarez

This letter is fictional and written for illustration. Replace every name, company, date and number with your own facts.

Name the languages and datastores from the job ad that you have really used, such as Python and PostgreSQL, rather than listing every technology you have touched.
Describe one concrete problem you solved, like duplicate transactions or a slow query, and state the change you made in a single sentence.
Mention collaboration with front-end, QA or DevOps colleagues, since back-end work is rarely done in isolation.
Use numbers only when you can verify them, such as latency before and after, and otherwise describe the outcome plainly.
Link to a repository or API documentation sample only if it is public and you are permitted to share it; keep proprietary details out.

Should a back-end developer cover letter list every technology?

No. Pick the languages, databases and tools relevant to the role and show them in context. The resume can carry the full skills list, while the letter explains how you used a few of them.

How technical should the letter be?

Technical enough to be credible, but readable by a recruiter too. Name the tool and the problem, such as adding indexes for reporting queries, and avoid deep implementation detail that belongs in an interview.

Can I include projects outside work?

Yes, especially if you have limited professional experience. Mention one or two personal or open-source projects that match the role, and be clear about your own contribution and what the project does.