Use this utility to extract the private key used by Keycloak to sign JWTs.
You can use the output of this program on jwt.io to forge valid JWTs.
You will need to connect via VPN to the target environment and port-forward the remote server with:
kubectl port-forward postgresql-postgresql-0 5432
Read the remote db username/password with:
vault read secret/doodle/ENVIRONMENT/keycloak/database
and update Postgres.java accordingly.
Run App.java. In the output you will find the key that you can copy and paste into jwt.io.