Learn Italian: Loro mi hanno chiesto se il profilo è compatibile. - They asked me if the profile is compatible.

In this lesson on indirect speech, se translates to 'if' or 'whether'. You use it to report a 'yes/no' question. The original direct question was likely 'Il profilo è compatibile?' (Is the profile compatible?). When reporting it to someone else, you simply bridge the main phrase and the question with se.

Why do we use the pronoun mi before the verb instead of saying hanno chiesto me?

The verb chiedere (to ask) requires an indirect object, meaning in Italian you technically ask 'to' someone (chiedere a qualcuno). The pronoun mi means 'to me' and must go right before the conjugated verb hanno chiesto.

Since they asked in the past (hanno chiesto), why is the second half in the present tense (è)?

You can keep the reported question in the present tense if the fact is still true right now (the profile is currently compatible). If you wanted to match the past tense context, you could use the imperfect tense and say se il profilo era compatibile, which is also perfectly correct.

I learned that se sometimes triggers the subjunctive. Can I use the subjunctive sia instead of è here?