About PriceWarden
PriceWarden is a price comparison app for shoppers in Canada, currently in development. Someone scans a product's barcode, and the app ranks the offers it can find by true total: price, shipping, sales tax and duties, in Canadian dollars. People can also keep a watchlist and be alerted when a price drops. The home page says more.
If PriceWarden contacted your service
To do that, PriceWarden's server requests data from product databases,
stores, price data services and the Bank of Canada. Every request identifies
itself with a User-Agent header that starts with PriceWarden/
and links to this page, for example:
PriceWarden/1.0 (+https://pricewarden.drbyte.org/about)
These requests come from PriceWarden's server, not from people's phones.
What it asks for
| Request | When |
|---|---|
| Product details for a barcode | When someone scans or searches for a product PriceWarden does not already know. The answer is kept, so the same barcode is not looked up again for each person who scans it. |
| Offers and prices for a known product | On a schedule, only when the data PriceWarden holds for that product is due to be renewed. Products on someone's watchlist come first, then products scanned recently. |
| Exchange rates | Once each business day, after the Bank of Canada publishes its daily rates. |
How it asks
- It uses only the APIs and data feeds a provider publishes for this purpose, with our own key or account where one is required, under the provider's terms.
- It does not crawl. It does not follow links, does not fetch pages to discover other pages, and does not try to get past sign-ins, paywalls or CAPTCHAs.
- Each provider has its own limits in PriceWarden: a minimum time between requests and a daily cap, set within that provider's published limits.
- If a service says it is busy or that we are sending too much (for
example HTTP 429 or 503), PriceWarden waits at least as long as any
Retry-Afterheader asks, and waits longer after repeated failures. - Requests time out instead of holding connections open.
- Where a service allows it, keys are sent in headers rather than in the URL.
What a request contains
Only what is needed for the lookup: a barcode, product identifiers or search words, and, where a quote depends on location (shipping, or stock at nearby stores), a postal code or province. A request never contains the name, email address, account or device identifier of anyone who uses PriceWarden.
Asking us to change or stop
If our requests cause you a problem, or you want them to stop, write to support@pricewarden.drbyte.org with the User-Agent you saw, roughly when, and what you would like us to do. We will slow down or stop as you ask. You may also block the User-Agent; PriceWarden will not try to get around a block.