Connection List Scalability

Fetching entire follower lists in a single unbounded query is a time-bomb proportional to your most-followed user. At 10,000 followers, a findMany with no take limit loads tens of thousands of joined records into memory, blows through Supabase row limits, and produces multi-second response times. This is a performance-efficiency failure under ISO 25010:2011 — the system cannot maintain acceptable response times as data volume grows. Power users are exactly the accounts that drive retention; making their profiles unusably slow is a direct business impact.

Switch follower and following list endpoints to cursor-based pagination in app/api/users/[id]/followers/route.ts. Cap the maximum page size at 100 and return a nextCursor so the client can load more incrementally.

// app/api/users/[id]/followers/route.ts
export async function GET(req: Request, { params }: { params: { id: string } }) {
  const url = new URL(req.url)
  const cursor = url.searchParams.get('cursor') ?? undefined
  const limit = Math.min(parseInt(url.searchParams.get('limit') ?? '20'), 100)

  const rows = await db.follow.findMany({
    where: { followedId: params.id },
    take: limit + 1,
    skip: cursor ? 1 : 0,
    cursor: cursor ? { id: cursor } : undefined,
    orderBy: { createdAt: 'desc' },
    select: { id: true, follower: true }
  })

  const hasMore = rows.length > limit
  const items = hasMore ? rows.slice(0, limit) : rows

  return Response.json({
    followers: items.map(r => r.follower),
    nextCursor: hasMore ? items[items.length - 1]?.id : null
  })
}