All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Working in a site specialized in comparing hotels so that people choose the best quality service or the lowest price is permissible if it is free from promoting falsehood and what is not permissible, such as mentioning, when giving preference to some hotels over others, that one of them provides wine, night clubs, gambling, and so forth. So, if you abstain in your work from what is not permissible according to the Sharee'ah, then there is nothing wrong with your work because, in that case, you will be guiding (people) to permissible benefits and legitimate services and you do not know anything about the customer's situation and his original intention (purpose).
This kind of work is like brokerage. Al-Bukhari wrote a chapter entitled:
“Chapter on the commission of brokerage” in which, he stated: "Ibn Sireen, 'Ataa’, Ibraaheem and Al-Hasan are of the view that there is anything wrong with a broker receiving a commission.” [End of quote]
The fact that most of the hotels are not governed by the rules of the Sharee’ah, then this does not prevent from renting in the hotel or guiding people to it, as in principle the hotel provides the service of accommodation, unless the person knows the intention of the client and that he wants to commit what is forbidden; in such a case, you should not guide him.
For more benefit, please refer to Fataawa 308935, 227188 and 88674.
Allah knows best.