First of all, our proxy is just that, a proxy. It sends data on behalf of another endpoint. To ensure proper security, you should be using an end to end encryption technology, which means that our proxy servers would only have access to the encrypted packets. HTTPS, TLS, or the like should be employed where necessary.
For HTTP or SOCKS outbound proxies, we store just enough details about the request to provide you the logs you see in the dashboard and for billing purposes (request limits). We store the time of each request, the account (username), the source (IP), the destination (URL or IP), and the status code for the request.
For inbound proxies, we store the time of the request, the account (username), the source (IP), the destination (generally a URL), the HTTP status code, the HTTP request type (GET, POST), and the number of bytes in the request.