Bulk reject Matrix invites

bulk-reject.sh

access_token=SECRET

# if your sync is large you may need to run this a few times until it completes rather than storing a timeout error
curl "https://matrix.org/_matrix/client/r0/sync?access_token=$access_token" > sync.json

for i in `cat sync.json | jq -r '.rooms.invite|keys|join(" ")'`
do echo $i
  curl "https://matrix.org/_matrix/client/r0/rooms/$i/leave?access_token=$access_token" --data '{}'
  sleep 5
done

Changing the sleep 1 in line 3 to sleep 4 or 5 may help to avoid rate limiting.
Debian users may need to apt install jq if it isn't already installed (users of other distributions may need to do something similar).

done :)

What is access token and where do I get it?

Update: typelocalStorage.mx_access_token to Firefox developer console on riot.im tab.

Also, changing the first curl command to curl -v -H "Accept-Encoding: gzip" "https://matrix.org/_matrix/client/r0/sync?access_token=$access_token" | gunzip > sync.json will speed up downloading the initial sync.

This is now obsoleted by the bulk invite reject feature in settings on riot.im/develop

If anyone is here looking for a way to bulk reject invites because they can't find such an option in Element anymore, it still exists. It won't show up until you actually have at least one pending invite.

You will find it in Security and Privacy, just scroll down to Bulk Options, right before Encryption.