Do I need a subscription to use an indoor security camera?

No. Cameras from eufy and TP-Link Tapo are repeatedly recommended in specialist subreddits like r/homeautomation and r/Tapo specifically because they record locally to a microSD card with no monthly fee. Ring, by contrast, gates most useful features — event recording, person alerts, video history — behind its Ring Home subscription, a point both PCMag and Tom's Guide call out in their Ring Indoor Cam Plus reviews.