Blocked content and sealed messages
How Kistrl keeps a stranger's message from reaching outside its frame.
Every message is sealed
Kistrl opens each message in its own sandboxed frame. Inside that frame a message cannot run scripts, submit forms or make requests to other servers. This applies to every message, from every sender.
External content from new senders
Many messages point to images and fonts stored on the sender’s servers. Loading them tells the sender that you opened the message.
For a sender you have not let in yet, Kistrl shows this notice instead:
External content is blocked. Loading it contacts URLs chosen by the sender.
Choose Load content if you want to see it for that message.
Senders you have let in
Once you route a sender to the Inbox, the Feed or Paper trails, Kistrl fetches their external content for you and stores a copy. Your browser loads that copy from Kistrl and does not contact the sender’s servers.
If some content could not be fetched, Kistrl says so and offers Retry.
Links
Links in a message open in a new tab. Check where a link goes before you follow it, especially in mail from someone you do not know.