How to get users from Keycloak REST API?
You need two steps
first get an access token from the admin-cli client of the master realm
second call the admin rest api with the access token, set Bearer as prefix in the Authorization header.
# get an access token
curl -X POST \
https://<HOST>/auth/realms/master/protocol/openid-connect/token \
-H 'Accept: application/json' \
-H 'Content-Type: application/x-www-form-urlencoded' \
-H 'cache-control: no-cache' \
-d 'grant_type=password&username=<USERNAME>l&password=<PASSWORD>&client_id=admin-cli'
# get all users of gateway realm, use the token from above and use Bearer as prefix
curl -X GET \
https://<HOST>/auth/admin/realms/gateway/users \
-H 'Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkI...' \
-H 'cache-control: no-cache'
403 = probably you don't have permission to view users. You need to define Client Roles
for used user and assign view-users
role: