Online mental health self-help services are of societal importance and increasingly popular. Therefore, we have developed an online platform offering free self-help to the Turkish public with modules based on Cognitive Behavioral Therapy (CBT) targeting depression, anxiety, and stress respectively. The main purpose of this study is to describe the user profile of this platform. A pre-intervention self-report assessment including general demographic information and the Brief Symptom Inventory questionnaire during October 2020 until September 2022. 8331 participants completed the assessment and created an account out of the 11.228 users who registered during a two-year period, of which 8.331 (74%) completed the assessment and created an account. The majority of these users were female (76.17%), highly educated (82%), single (68%) and actively studying or working (84%). Slightly more than half (57%) of the platform user had not received psychological assistance before, while those who did receive previous assistance indicate to have benefitted from that (74%). The psychological symptoms of users are widely distributed, encompassing a broad range of user profiles. Approximately half of all users actively used the platform, while the other half did not complete any module. Among active users, the course “coping with depressive mood” was the most popular (41.45%), followed by “coping with anxiety” (37.25%) and “coping with stress” (21.30%). Offering a free online CBT self-help platform to the Turkish public seems feasible, with strong uptake among both man and woman struggling with a variety of psychological symptoms. Further research is needed to assess user satisfaction and change in symptoms over time during platform use by means of a feasibility trial.