Generally, Jains avoid tapioca starch during strict fasting or in many Jain food practices, because tapioca comes from a root/tuber, and root-based foods are usually avoided in Jain dharma due to ahimsa and the belief that they contain more living beings and disturb more life when harvested.

However, tapioca starch as a processed ingredient may be treated differently by different Jain families and traditions, especially if it is used in permitted ways on non-fasting days. So the answer is:

• Strict Jain observance: usually no
• Some household practices: may differ, depending on tradition and ingredients

If you want, I can also tell you how tapioca compares with other foods like potato starch, corn starch, arrowroot, and sabudana in Jain diet rules.