With your API key

Every checker endpoint also answers under /api/v1 for an API key: POST /api/v1/free-proxy/check streams, GET and POST /api/v1/proxy-check answer in one response. Same bodies, same result rows, and your account's tier: ten times the requests and 3,000,000 proxies a day, counted on the account rather than on the address, so a whole team behind one office connection is not squeezed into one person's budget. Any key works; checking spends nothing and needs no scope. Errors come back in the usual /api/v1 shape, { "error", "code" }.