Sold resale prices from Vinted (7 European countries) and eBay US, with median and price range.
Swanum Comps API is a free Shopping API that requires apiKey authentication, is served over HTTPS and does not support CORS, so it should be called from a server.
Quickstart, authentication, endpoints, response schema, errors and code samples in curl, Python, JavaScript and PHP for the Comps sold prices API.
Details from swanum.com.

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Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Sold resale listings from Poshmark with median price, days to sell and net payout after fees
WooCommerce REST APIS to create, read, update, and delete data on wordpress website in JSON format
Yes. The Swanum Comps API is listed in the Shopping category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The Swanum Comps API uses apiKey authentication, so you need to register for credentials before making requests.
Not directly. The Swanum Comps API does not allow CORS, so call it from a server, serverless function or proxy instead of front-end JavaScript.
Yes. The Swanum Comps API is served over HTTPS, so it's safe to use in production.