A public league needs only its ID. Leave the team number blank to see a list of the league's teams.
My ESPN league is private
Read this first. ESPN has no supported way to connect an app to a private
league: no OAuth and no read-only token. The other platforms here use one of those, so they need
nothing sensitive. The only way in is your two ESPN session cookies. Those aren't limited to
fantasy. Anyone holding them can act as you anywhere on ESPN until they expire.
If that's more access than you want to give, use
Sleeper, Yahoo
or a public ESPN league, which needs only its ID.
If you continue, the cookies are encrypted before they are stored, never
shown back to you, never written to logs, and deleted the moment you disconnect or delete your
account. They are used for one thing: reading your roster. The
privacy policy has the details.
In a browser signed in to ESPN, open developer tools and go to Application >
Cookies > espn.com. Copy the values of espn_s2 and SWID.