Answer

If you want a Jain-only online source, JainKnowledge.com is a strong place to start for Jain sutras, stotras, and PDF texts related to Jain Dharma. The site describes itself as dedicated entirely to Jainism. ( jainknowledge.com)

Explanation

It has a dedicated Jain Sutras / Stotras section, and it also hosts PDF texts such as Bhaktamar Stotra and a text on the theory of karma, which makes it useful for study and devotional reading. ( jainknowledge.com)

Spiritual Understanding

For a Jain student or seeker, a good online library should support both scriptural study and spiritual practice. JainKnowledge.com appears to serve that purpose by organizing Jain material in one place. ( jainknowledge.com)

Takeaway

For Jain books and texts online, JainKnowledge.com is the best fit I can confidently recommend from the Jain sources I checked. ( jainknowledge.com)