How do you address the reader in a letter of reference?

I’ve been taught to use “Dear Sir/Madam” if you don’t know the name or gender of the person you’re writing to. And finish with “Yours faithfully” rather than “Yours sincerely”.

I do prefer “Dear Sir or Madam” over “To whom it may concern.” A modern variation on that might be “Dear Employer.(or other noun as the situation warrants).”

“To whom it may concern” is the most common one even tho a bit impersonal or old fashioned.

Just have each person decide for themselves which salutation is most natural for them. Otherwise it could look too formulaic.

As the esteemed @Buttonstc says, each person writing a letter should determine that him or her self.

Some people refuse to write to just whoever. They need to know who they are addressing. I’m not sure why.

From the info given in the Q, I was assuming that these are general letters of reco. from past colleagues which could be used in applications for employment.

That would make it impossible to be able to specifically know upfront who the reader (or likely several readers) might be.

Obviously, if it is for one particular person in charge of hiring for a particular firm, then addressing them by name is ideal. It just didn’t sound as if that were the case from the way the Q was asked.