Privacy Policy

Spread browser extension · Last updated 9 September 2026

Spread has no accounts, no analytics, no advertising, and no tracking. It does not build a profile of you, and it does not watch your browsing.

The short version. On product pages at the six supported retailers, Spread sends that product's title and price to its own service so it can build a price history and find prices elsewhere. What gets stored is a fact about the product — "this cost $328 at Best Buy at this time" — with no record of who saw it. Nothing you view anywhere else is ever sent.

What Spread sends, and when

Spread transmits data at two moments, and no others.

1. When you open a product page at one of the six supported retailers, Spread sends that product's details so its price joins the product's price history. This is what lets Spread tell you "this is the lowest price in 60 days" — a claim that is impossible without having recorded the earlier prices.

2. When you click Compare price, Spread sends the same details again to look up what other retailers charge.

Nothing is sent for any other page. Non-product pages on those six sites send nothing, and every other website you visit is invisible to Spread — the extension cannot run there at all.

Data	Why
Product title	To identify the product and find it at other retailers
Price, brand, model number	To record the price and confirm a match
Retailer name	To attribute the price and exclude the site you are on
A random install ID	Used only to rate-limit abuse of the free service. It is a random value generated at install, not derived from anything about you or your device. It is checked against a short-lived counter and is never stored alongside a price observation — recorded prices carry no identifier of any kind.

How price history works

A recorded observation is three values: the retailer, the price, and the time. It is filed under the product, not under a person, and it is indistinguishable from an observation made by anyone else. There is no way to reconstruct from the stored data which products a given person looked at, because the link is never written down.

Spread also declines to record anything it cannot identify confidently. If a product's brand and model cannot be established from the page, no observation is stored at all — merging two different products into one price history would produce prices that were never real.

What Spread never collects

Your name, email address, or any account information — there are no accounts.
Your browsing history. Spread runs only on product pages at six retailers and can see nothing else; what it records there is filed under the product, never under you.
Cookies, login state, form contents, payment details, or anything in your cart.
Your IP address in any stored form. It is visible to the server in transit, as with any web request, and is not logged or retained.
Advertising or cross-site tracking identifiers. Spread sets none and reads none.

Where your data goes

Product details are sent to the Spread comparison service, which runs on Cloudflare Workers. That service queries retailer product APIs (Best Buy and eBay) to find matching listings. In cases where matching is genuinely ambiguous, two product titles — and nothing else — may be sent to Anthropic's Claude API to confirm whether they describe the same item.

Spread does not sell, rent, or share data with anyone else, and it has no advertising partners.

What is stored, and for how long

On your device: a count of comparisons made and the total price differences found, so the toolbar popup can show your savings. This never leaves your browser. You can erase it any time from Spread's settings page.
On the server: price observations are kept for up to a year, keyed by product and carrying no identifier. Comparison results are cached for 6 hours and product-match results for 90 days, both keyed by product. Rate-limit counters expire within 2 hours.

Permissions, and why each is needed

storage — saves your local savings total and settings on your device.
activeTab — lets the toolbar popup tell you whether Spread works on the page you are looking at.
Access to six retailer sites — Amazon, Target, Walmart, Best Buy, eBay and Costco. Spread reads the product title and price on those pages and cannot run anywhere else.

Children

Spread is not directed at children under 13 and collects no personal information from anyone.

Changes

Material changes to this policy will be reflected in a new extension version and in the date above. The full history is public in the source repository.

Contact

Questions or requests: open an issue on GitHub.