Early Maariv on Motzaei Shabbos

Question: My neighbour has started a minyan for maariv in his house on Motzaei Shabbos. They begin 15 minutes before nacht. Is this ideal?

Answer: The Gemara (Rosh Hashana 9a; Yuma 81b) teaches that there is a mitzva of tosefes Shabbos, to add on a little bit of time both at the beginning and at the end of Shabbos. One should therefore endeavour to bring Shabbos in a few minutes early and not end it until a few minutes after nacht (See Mishna Berura 261:19).

Thus, the Shulchan Aruch (OC 293:1) writes that one should delay davening maariv on motzaei Shabbos in order to add some time onto Shabbos. The Mishna Berura (293:1) writes that this is the universal practice. The Rema adds that there is even a minhag to say the opening words of maariv, vehu rachum, very slowly to add on a few extra seconds.

The Shulchan Aruch (OC 293:3) writes that in extenuating circumstances, such as one had a pressing mitzva matter, they can daven maariv after pelag hamincha. Nonetheless, the Magen Avraham (293:4) writes that the acharonim disapprove of this as it doesn’t look right when most people are waiting until nacht and some are davening earlier. The Mishna Berura (293:9) adds that we also need to be concerned that people may come to perform melacha before it is nacht.
In conclusion, it is important to wait until nacht to daven maariv on Motzaei Shabbos.