Compute aggregate ratings

In this guide, you’ll learn how to compute average ratings for products and sellers from your own server code. This is useful when surfacing a rating on a storefront page or in a custom API route. The Review module service computes averages on demand instead of storing a denormalized column, so the numbers always reflect the current set of reviews. Resolve the service from the container to use its rating helpers.

Average for one target

getAvgRating returns the average rating for a single product or seller:

src/api/custom/route.ts

import type { MedusaRequest, MedusaResponse } from "@medusajs/framework/http"
import { MercurModules } from "@mercurjs/types"

export async function GET(req: MedusaRequest, res: MedusaResponse) {
  const reviewModuleService = req.scope.resolve(MercurModules.REVIEW)

  const rating = await reviewModuleService.getAvgRating("seller", "sel_123")

  res.json({ rating })
}

The first argument is the target type ("product" or "seller"), the second is its id. The method returns null when the target has no reviews yet.

Ratings for a list

For list views, getProductsWithRating and getSellersWithRating return records with their average rating joined in, so you don’t fan out a call per row:

const reviewModuleService = container.resolve(MercurModules.REVIEW)

const sellers = await reviewModuleService.getSellersWithRating([
  "id",
  "name",
])
// => [{ id, name, rating }, ...]

Pass the fields you want selected from the target table; each returned record gains a rating field with the average.

These helpers average across a target’s linked reviews. Combine them with your own status filter if you only want published reviews to count toward the public number.

Store

Catalog

Offer

Attribute

Product Edit

Order Group

Commission

Payout

Review

Average for one target

Ratings for a list

​Average for one target

​Ratings for a list

Average for one target

Ratings for a list