The 30-second cover letter (and when to skip the long version)

Conventional advice says a cover letter should be one page, four paragraphs, formatted in PDF. For a senior role at a structured company that's still good advice. For most other applications — startups, recruiters' inboxes, internal referrals — the optimal cover letter is three sentences in the email body.

The three-sentence template

1. Why this role, in one specific reference. "Saw your post about the checkout p95 latency — I shipped two latency reductions in the last 18 months."
2. Strongest credential, with a number. "Most relevant: dropped a payment API from p95 = 1.2s to p95 = 380ms over six weeks at [Company]."
3. What you want next. "CV attached. Happy to do a 30-min screen this week."

That's the whole letter. It works because:

• The recruiter has already seen 200 cover letters this month. Yours stops the scroll because it's short.
• The hook (sentence 1) shows you read past the careers page.
• The credential (sentence 2) gives them something concrete to forward to the hiring manager.
• The CTA (sentence 3) removes friction.

When to write the longer version

Use the four-paragraph format when:

• The application platform forces a multi-paragraph cover-letter field.
• The role explicitly asks for one ("a 1-page cover letter is required").
• You're early-career and your CV alone doesn't tell a clear narrative.
• The role is at a company that values written communication for the role itself (technical writer, product manager, comms).

When the short version wins

• Email-direct outreach to a recruiter or hiring manager.
• Internal referral: the referrer is forwarding you anyway. The shorter the better.
• Startups, especially seed/Series A. They appreciate signal-to-noise.
• Senior roles where the CV does most of the talking.

What to never do (in either version)

• "I am a hardworking, passionate, self-motivated professional…" — the recruiter's eyes are already glazed.
• Restating your CV. They have it open.
• "Please find attached my resume" — the formatting makes that obvious.
• Long quotes from the company's mission statement. Flattering them isn't the same as showing fit.

The only time a cover letter matters is the 15 seconds before the recruiter decides whether to open your CV. Make those 15 seconds count, then get out of their way.