thank you for your attention. I was reading about the instagram sandbox and there were some doubts, maybe some of you have already used this feature and can answer me, my doubt is.
you have get your app reviewed and approved by Instagram for public_content
scope permission, and go live mode, then you can make API call and access any public user's photos, you dont need permission from that user.
You cannot access other user's data in sandbox mode, you can invite other user to your sandbox and if he accepts then you can access that user's latest 20 photos only.