He matches skilled people with those who are seeking services, and takes a percentage of every transaction plus monthly subscriptions from the people with skills

Firstly:

Ruling on acting as an intermediary in return for pay, matching skilled people with those who are seeking services

It is permissible to work as an intermediary matching skilled people with those who are seeking services, in return for a percentage of the fee for every job for which he matched the two people. This comes under the heading of brokerage, on condition that the work in question is permissible.

As for jobs in which the website did not act as an intermediary, and played no role in helping people to find the skilled person, there is no reason for the website to take a percentage of the worker’s fee in that case.

An example of that is if a connection is established between the skilled person and the client, and after the first job that was done through the help of the website, the client asks him to do other jobs. In that case, the website does not have the right to a fee for acting as a broker, except in the case of the first job, to the exclusion of any jobs that followed that.

For more information, please see the answer to question no. 278377 .

There is nothing wrong with making the fee for brokerage a set amount or a percentage of the fee for any work done.

In Fataawa al-Lajnah ad-Daa’imah (13/131), it says: It is permissible for the broker to charge a fee that is a known percentage of the price for which the item is sold, in return for connecting people; he may collect this fee from the seller or the purchaser, according to the agreement, without being unfair or causing harm. End quote.

Secondly:

Ruling on charging both  a monthly subscription fee and a percentage of the fee paid to the skilled person

It is not permissible to charge a monthly subscription fee to the skilled person, and at the same time take a percentage of the fee for every job done, because the brokerage fee is this percentage. Therefore the monthly subscription fee comes under the heading of consuming people’s wealth unlawfully.

But if the website provides a space in which people can advertise their skills throughout the month, then in that case there is nothing wrong with charging a monthly subscription fee for providing this space, and bringing client comes under the heading of brokerage.

If the broker does other things to find clients, apart from providing space for skilled persons to advertise, then he deserves payment for that work, commensurate with his effort. If he does not do any other things, then he does not deserve to be paid twice for merely providing this space. What we mean by the two payments in this case is the monthly subscription and the percentage that he charges.

Combining leasing something and brokerage is permissible, even if that is stipulated in a condition. The scholarly view that is most likely to be correct is that it is permissible to put a contract within another contract, provided that it does not lead to riba, which is prohibited.

This is the view of the Shaafa‘is, and of Ahmad according to one report, in contrast to the majority.

Please see: al-Mu‘aamalaat al-Maaliyyah by Shaykh Abu ‘Umar ad-Dubyaan (5/373).

Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: The correct view is that if someone stipulates another contract in a sale transaction, that condition is valid and the sale is valid, except in two cases… The first of which is if he stipulates a loan from which he benefits. In that case, it is not permissible because it is a loan that brings benefits, so it is riba.

The second is if it is a loophole to allow riba. "Ash-Sharh al-Mumti‘ (8/239)"

And Allah knows best.