# Challenges types
At Oktonine, there are three types of challenges that can be created by a company representative. The challenge type depends on how the company wants to collaborate with schools.
Challenges proposed by companies (outside a call-for-challenges) are only displayed at Oktonine's ProjectStore.
# Private challenge
If a company wants to collaborate with a specific teacher within a specific school, it should publish its challenge as Private. The company needs to add this teacher as a collaborator of the challenge.
By doing that, the challenge will only be visible to this teacher.
# Public challenge
If a company wants to provide a challenge for anyone using Oktonine, it should publish its challenge as Public. The company doesn't have to specify a collaborator.
By doing that, the challenge will be visible for everyone using Oktonine, and the company won't be able to see who is working on its challenge.
# On-demand challenge
If the company wants to work with students and teachers from any school, without preferences, it can define its challenge as On-demand.
The company will receive applications from teachers to collaborate with them.
If the company accepts a teacher's request, they can convert the challenge into a Private one.