Where to advertise PhD positions without paying a fee? We have several opening in our group working in the field of computer science and electrical engineering (more specifically digital system design). We put an advertisement in our webpage and also another in the university portal. But we don't have applicants yet. I was looking for some websites to advertise the positions. I found that most of these websites (e.g. researchgate) ask for money. Do you know any website for advertising phd positions for free?
Euraxess may be an option. Its openings are quite heterogeneous (sciences and humanities). Despite the name, it is not restricted to European countries.

There are other free scholarship aggregators like scholarship-positions.com. If you search academia.stackexchange you may be able to find others.

Also, you may be able to find reddit channels associated to your area. At least in computer science it is not uncommon to see such openings posted there.

Another option is trying to locate a google group where other labs in your field post their openings.