How to Build a Feed API in Node.js

How to Build a Feed API in Node.js

A feed API returns a paginated list of items (users, posts, products). Here is how to build one in Node.js.

The Endpoint

GET /api/v1/feed?skip=0&limit=20

Returns a paginated list of items for the authenticated user.

The Controller

exports.getFeed = asyncHandler(async (req, res) => {
  const skip = parseInt(req.query.skip) || 0;
  const limit = Math.min(parseInt(req.query.limit) || 20, 100);

  const filter = { _id: { $ne: req.user.userId } };
  if (req.query.gender) filter.gender = req.query.gender;
  if (req.query.minAge || req.query.maxAge) {
    filter.age = {};
    if (req.query.minAge) filter.age.$gte = parseInt(req.query.minAge);
    if (req.query.maxAge) filter.age.$lte = parseInt(req.query.maxAge);
  }

  const [items, total] = await Promise.all([
    User.find(filter).select('firstName photoUrl about age gender').skip(skip).limit(limit).lean(),
    User.countDocuments(filter)
  ]);

  res.json({ data: items, total, skip, limit });
});

Exclude the Current User

The feed should not show the user themselves. Filter with _id: { $ne: req.user.userId }.

Exclude Already-Swiped Users

For a dating app, exclude users the current user has already swiped on:

const swipedIds = await ConnectionRequest.find({ fromUserId: req.user.userId }).distinct('toUserId');
const filter = { _id: { $nin: [req.user.userId, ...swipedIds] } };

Cap the Limit

Math.min(parseInt(req.query.limit) || 20, 100). Prevents abuse. Without a cap, a client can request 10000 items.

Use .lean() and .select()

.lean() skips hydrating full documents. .select() limits fields. Together they reduce memory and payload.

Return Total

{ data: items, total, skip, limit }. The client can show "showing 1-20 of 432" and decide whether to show a next button.

Run Queries in Parallel

Promise.all([find, countDocuments]). Both queries run at once. Faster than awaiting them sequentially.

Index the Filter Fields

Index the fields you filter by. For a feed, index gender, age, and any other filter. Use compound indexes if you filter on multiple fields together.

The Takeaway

Build a feed API with GET /feed?skip=&limit=. Exclude the current user and already-swiped users. Cap the limit. Use .lean() and .select(). Return total. Run find and countDocuments in parallel with Promise.all. Index the filter fields.