Handling a privileged position.
WHAT AN EXTENSION CAN DO
Read everything on pages it has access to, including what users type.
WHY THAT MATTERS
It is among the most privileged positions in a user's browser.
WHAT TO NEVER DO
Collect more than the feature requires Send page content to a server without clear disclosure Include remote code, which the platform prohibits Sell or transfer user data contrary to your stated policy
WHY THAT LAST POINT
Extensions have been sold and repurposed to harvest data, and enforcement is severe.
WHAT TO DISCLOSE
What you collect, why, and where it goes.
WHAT TO REQUIRE
A privacy policy, accurate and published.
WHAT TO HANDLE CAREFULLY
Content from pages, which is untrusted input Messages from web pages, which any site could send
WHAT TO VALIDATE
Every message, including its origin.
WHAT TO SET
A strict content security policy.
WHAT TO NEVER INCLUDE
Secrets in the extension package.
WHY
It is downloadable and readable by anyone.
WHAT TO ROUTE THROUGH YOUR SERVER
Anything requiring a secret.
WHAT TO REVIEW
Dependencies, which run with your permissions.
