The hardest single thing about a cover letter is the register. Too informal and you sound careless; too formal and you sound like you've never met another working person. Models default hard toward the second failure because it's safer on average, which is why so many AI-drafted cover letters sound like they're from the 1890s.
Look at the company, not the genre
The right register comes from the employer, not from the genre conventions of a cover letter. A four-person design studio in Lisbon and a London law firm are not asking for the same letter. Read the company's careers page, their blog, the way they describe themselves on LinkedIn. The register they use is the register they expect from you.
- Early-stage startup with a casual blog — first-name greeting, contractions, no preamble.
- Mid-size company with a formal careers page — name and title, full sentences, but no "Dear Sir or Madam".
- Traditional firm in law or finance — Mr/Ms and surname, full salutation, conservative paragraphing.
- Academic or grant application — formal, structured, no contractions.
Before
Dear Sir or Madam, I am writing to formally express my keen interest in the Senior Designer position at your esteemed organisation. It would be a great privilege to be considered for this role, and I sincerely hope you will find my qualifications suitable.
After
Hi Marta, I'm writing about the Senior Designer role you posted last Friday. I've been following the rebrand work your team did for Trustpilot — the typographic system in particular is the kind of project I want to be working on next.