The سنة أولى ثانوي app, developed by 3alim, is a free educational app available on the Android platform. The app caters to Algerian students and offers a wide range of subjects, including natural sciences, physics, mathematics, Arabic, Islamic education, French, English, history, geography, and technology. It also includes solved exercises, summaries, books, and exam papers with corrections.

The app is divided into two sections: the first section is for science and technology students, while the second section is for arts students. Both sections contain detailed lessons, summaries, and solved exercises. The app is user-friendly and easy to navigate, with all the subjects arranged in a clear and organized manner. With this app, students can access all the necessary material in one place, making studying and exam preparation more efficient and effective.