By Jewish Law A Shadchan is entitled to a fee.
The first halachic ruling on shadchanus is by Moses Isserles (1530- 1572), also known by the acronym Rema who ruled that a shadchan is an agent like a real estate agent who gets a fee and the shadchan can compel payment in bes din just like any debt owed.
For at least 500 years, a shadchan is an agent, not an employee and by Jewish law is entitled to a fee. Contrary to Jewish law, other pseudo-shidduch sites imply or overtly state that the shadchan by being paid makes it insidious and not entitled to payment. This is patently against halacha.
At the engagement, the shadchan gets paid.
Not so simple. Rav Spitz explains the many halochos:
Who is Entitled to Shadchan Fees?
Any person who makes a shidduch for someone else, whether it is a professional Shadchan or a friend, is entitled to a shadchan fee. This includes making a shidduch for relatives. If a close relative (i.e. brother, sister, brother-in-law) is a professional shadchan who had stated specifically they require a fee, or even if it didn’t cross their mind, but when the Shidduch was completed they demanded it, they are entitled to payment. However, in the case where they made the Shidduch as a favor to the son, family etc. as is commonly done, they are not entitled to payment.11
Obligation to Pay a Shadchan
If a Shadchan demands payment and a second party denies that he was the Shadchan, it is considered just like any monetary complaint adjudicated by Beis Din20. A person has to pay a Shadchan because he benefitted from his work21. In a case where a person approached a shadchan to make him an offer, it is a Machalokes if one pays because the Shadchan is considered a Kablan or for the same reason – because he benefited from his work. The difference being whether there is Baal Talin if one doesn’t pay in time.22
If the Shadchan Asks for more than the Market Price
If a shadchan asks for a fee which is 1/6 above the market rate, the person only has to pay the market value24, unless a Kinyan was made25, or even a handshake on the price which binds them to that agreement. If they paid already, then even without a Kinyan or handshake on the price, the shadchan does not return the money.26 If the shadchan was poor, then according to the Kitotz Hachosen, one must pay the Shadchan the full amount as it is considered a neder.27 The Netivos, however, argues that this is not considered an actual neder. If the Shadchan worked more than the accustomed amount of work, then even without a Kinyan, the person has to pay the agreed-upon price.28 In a case where one side didn’t pay the Shadchan for whatever reason, the Shadchan cannot demand that second side pay the obligation of the first.29
Where there is more than one shadchan, how the fees are split, where the engagement is broken, and under what conditions the shadchan not entitled to payment
These are complicated and no summary would do this justice, so please hear it directly from Rav Spitz