Does Moving My Finger During Prayer Invalidate It?

Does moving my finger during prayer invalidate it?
Dear questioner,
Thank you for your important question.
May Allah, Most High reward you for your desire to increase in knowledge.
Moving your small/pinky finger during prayer does not invalidate your prayer.
That movement which invalidates your prayer is defined as: “Any movement which if an outsider were to look at you, they would think that you are not praying.” [Kasani, al-Badai’ as-Sanai’/Ibn Abdin, Radd al-Muhtar]
Moving your little finger purposely is a disliked action in prayer.
And Allah alone knows best,
[Ustadh] Omar Popal
Checked and Approved by Shaykh Faraz Rabbani