Minimal viable alertmanager configuration without paging

I'm trying to get alertmanager running without paging. All I want to do is see the alerts on the alertmanager web page but I can't find a config which doesn't want to send pages somewhere.

If I exclude the config file I get an error.

component=configuration msg="Loading configuration file failed" file=alertmanager.yml err="open alertmanager.yml: no such file or directory"

I have commented out that file and the associated command but obviously it's mandatory. Can somebody point me to a config which works but doesn't want to send alert notifications anywhere?

Solution

I think super-minimal should be something like:

global:
  resolve_timeout: 5m
route:
  receiver: "null"
  group_by:
  - job
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 12h
receivers:
- name: "null"

Less minimal:

global:
  resolve_timeout: 5m
route:
  receiver: main
  group_by:
  - job
  routes:
  - receiver: "null"
    match:
      alertname: Watchdog
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 12h
receivers:
- name: "null"
- name: main
# Here define the receiver
# Add templates if necessary
#templates:
#- /etc/alertmanager/*.tmpl