Threaded Comments
Nested replies that stay readable eight levels down.
IntermediateWeb appSocial10–20hAI-buildable 4/5needs backendworth shipping
A comment system with arbitrary nesting, collapsing, sorting and optimistic posting. The hard part is presentation: naive indentation makes deep threads unusable on a phone, so at some depth the design has to change strategy rather than keep indenting.
UI
Logic
Useful
Hosting · Free tier, sleeps when idle
Deploys free on Vercel Hobby + Supabase free or Cloudflare Pages + Turso free.
Free database tiers pause or expire when a project sits idle, so this one needs occasional attention to stay up.
Deploy it and share a link.
Core features · 7
- Comments nest to arbitrary depth
- Any subtree collapses and expands with a reply count shown
- Replying posts optimistically and reconciles with the server
- Sort by newest, oldest or most replies
- Deep threads stop indenting and switch to a continuation style
- Editing and deleting your own comments, with deleted ones tombstoned
- The whole thread stays usable on a narrow screen
The interesting part
- Flattening a tree for rendering without losing structure
- Indentation strategy that degrades gracefully at depth
- Optimistic inserts that reconcile when the server assigns real ids
Once it works
- Add permalinks that focus a single subtree
- Add markdown in comment bodies
- Add a collapse-all control with recall
Suggested stack
reacttypescripttailwindsupabase