Offset Pagination vs Cursor Pagination in MongoDB

Offset Pagination vs Cursor Pagination in MongoDB

Two ways to paginate in MongoDB: offset (skip and limit) and cursor. Here is when to use each.

Offset Pagination (skip and limit)

const skip = parseInt(req.query.skip) || 0;
const limit = Math.min(parseInt(req.query.limit) || 20, 100);
const items = await User.find().skip(skip).limit(limit).lean();
const total = await User.countDocuments();
res.json({ data: items, total, skip, limit });

Pros:

• Simple.
• Client can jump to any page (skip=40 for page 3).
• Returns total, so the client can show page numbers.

Cons:

• Slow for large offsets. MongoDB scans the skipped docs.
• New items inserted between requests can cause duplicates or skips.

Cursor Pagination

const cursor = req.query.cursor ? new Date(req.query.cursor) : new Date();
const limit = Math.min(parseInt(req.query.limit) || 20, 100);
const items = await Message.find({ createdAt: { $lt: cursor } })
  .sort({ createdAt: -1 })
  .limit(limit)
  .lean();
const nextCursor = items.length === limit ? items[items.length - 1].createdAt : null;
res.json({ data: items, nextCursor });

Pros:

• Fast for large offsets. MongoDB uses an index on createdAt.
• Stable. New items do not cause duplicates or skips.

Cons:

• Client cannot jump to a page. Only next and prev.
• No total (would require a separate count query).

When to Use Offset

• The collection is small (< 10000 docs).
• The client needs page numbers ("showing 1-20 of 432").
• The client needs to jump to a specific page.

When to Use Cursor

• The collection is large (> 10000 docs).
• The client only needs next and prev (infinite scroll, feed).
• Performance matters.

Indexes

Both need indexes:

• Offset: index the sort field.
• Cursor: index the cursor field (e.g., createdAt). Without an index, cursor pagination is not faster than offset.

The Takeaway

Use offset pagination (skip and limit) for small collections or when the client needs page numbers. Use cursor pagination for large collections or infinite scroll (faster, stable). Both need indexes on the sort or cursor field. Cursor cannot jump to pages; offset can.