Most developers don't write cover letters. That's exactly why you should. In a stack of 200 applications where 180 are a bare resume and a LinkedIn URL, the candidate who writes three thoughtful paragraphs stands out like a console.log in production — impossible to ignore. I've talked to hiring managers, reviewed hundreds of applications, and tested different approaches myself. Here's everything I've learned about writing cover letters that actually move the needle for developer roles. Short answer: yes, but not for the reason you think. A 2025 ResumeGo study found that applications with tailored cover letters were 53% more likely to get an interview callback than identical resumes sent without one. For mid-level and senior roles, that number jumped to 72%. But here's what the data doesn't capture: most hiring managers I've spoken with say they don't require cover letters — they notice them. There's a difference. When a recruiter is scanning 50 applications in an hour, your resume gets 6-7 seconds. A cover letter is the only place where you control the narrative. Your resume says what you did. Your cover letter says why you care. Three specific situations where cover letters matter most: 1. Competitive roles at desirable companies. When Stripe, Vercel, or Shopify post a role, they get thousands of applications. A cover letter is your chance to be a person, not a PDF. 2. Career transitions. Moving from backend to frontend? From agency to product? Your resume will confuse people. A cover letter explains the story. 3. Roles at smaller companies. At a 20-person startup, the founder is often reading applications personally. They care about fit and motivation more than anything else. When cover letters don't matter: mass applications through job boards where the ATS is doing the filtering. If you're applying to 100 jobs a week, skip the letter and focus on keyword-optimized resumes. But if you're applying strategically to 5-10 roles? Write the letter. Forget the five-para