Is Hoshimiru really free? Does it have ads or affiliate links?
Yes, it is free. There are no ads, no analytics tags and no affiliate IDs.
Chrome extension (free)
Hoshimiru
See the real lowest price. This free Chrome extension compares prices including shipping and points in Amazon search results and shows the cheapest item under the same conditions. Different pack sizes are compared per unit, so you can see when the bigger size costs more.
The displayed price alone does not show what is really cheapest
A search on Amazon lists similar products from different sellers and in different pack sizes. A price may look low, but what you actually pay changes with the following.
- Shipping: depending on the seller and conditions, it may or may not be charged.
- Points: the points you receive lower your effective payment.
- Pack size: a larger pack can cost more per unit.
What Hoshimiru does
Cheapest for these conditions
Among the items matching your search conditions (for example, sparkling water 500ml, 24 bottles, label-free), Hoshimiru compares price + shipping − points and puts a green frame and a “cheapest for these conditions” badge on the lowest one.
Cheapest for the same product
When the same product appears from different sellers or in different sizes, it shows “cheapest for the same product” or “+8% for the same product”. When sizes differ, it compares per unit or per 100ml, so you can see when the bigger size is actually more expensive.
Sponsored listings included
Sponsored listings are compared on the same basis. Different products with different ingredients are not compared with each other. Items added by infinite scroll or paging are recalculated automatically.
A check before adding to cart
On a product page, if your last search contained a cheaper identical item, it warns you that a cheaper identical product exists. This helps you avoid adding the wrong one to your cart.
How to use
1. Install
Add Hoshimiru from the Chrome Web Store. No account or setup is needed.
2. Search on Amazon.co.jp
Search with keywords as usual. The items on the results page are compared automatically using the amount including shipping and points.
3. Look for the green badge
The item with a green frame and the “cheapest for these conditions” badge is the lowest among those matching your search. Items within 5% of the lowest (adjustable in settings) are shown in yellow.
Privacy
- All price comparison is done on your device. Your browsing history, personal information and purchase information are not sent anywhere. We have no server.
- The only thing that can leave your device is the optional feedback form (Google Forms) that you open and submit yourself. Nothing is sent unless you submit it.
- Settings and the comparison data of your last search are stored only on your device (chrome.storage.local).
- No ads, no analytics tags and no affiliate IDs.
Limits
- The quantity is read automatically from the product title, so it can be wrong.
- Differences in ingredient amounts are not judged. Please also check for yourself whether items are really the same product.
- Changes to the Amazon site can stop it from reading the pages. In that case a notice is shown in the popup.
- It works only on search result pages and product pages of amazon.co.jp.
Frequently asked questions
Common questions about this service. See the site-wide FAQ for more.
Are my browsing history or purchase information sent anywhere?
No. All price comparison is done on your device, and your browsing history, personal information and purchase information are not sent. The only thing that can leave your device is the optional feedback form (Google Forms) that you open and submit yourself; nothing is sent unless you submit it.
Is the “cheapest” judgement always correct?
Not always. The quantity is read automatically from the product title and can be wrong, and differences in ingredient amounts are not judged. Please also check the product details before buying.
When installing, Chrome says “This extension is not trusted by Enhanced Safe Browsing.”
If Chrome's Enhanced Safe Browsing is turned on, this confirmation appears for extensions from new developers that have only recently been published. It does not mean a problem was found in Hoshimiru (it has passed the Chrome Web Store review). It stops appearing after the developer has followed the policies for a few months. To install, choose “Continue to install”.
Try Hoshimiru
It is free. Just install it and the real lowest price appears in your Amazon search results.
Even if the brief is still fuzzy, you can start with a free consultation
Share your current situation briefly and we'll come back with a way forward and a rough cost range.
- First consultation free
- Reply within 2 business days
- Online across Japan (in Japanese)
- Multilingual support by email & chat