Blueprint for Sync Two Switches Bi-directionally in Home Assistant

sync_two_switches.yaml

blueprint:
  name: Sync Two Switches Bi-directionally
  description: Keeps two switches perfectly in sync. If you turn one on/off, the other follows, while preventing infinite loops.
  domain: automation
  input:
    switch_1:
      name: Switch 1
      description: The first switch to keep in sync.
      selector:
        entity:
          domain: switch
    switch_2:
      name: Switch 2
      description: The second switch to keep in sync.
      selector:
        entity:
          domain: switch

variables:
  # We bind the inputs to variables so the Jinja templates below can read them.
  switch_1_entity: !input switch_1
  switch_2_entity: !input switch_2

mode: parallel
max: 10

triggers:
  - id: "switch_1"
    entity_id: !input switch_1
    trigger: state
  - id: "switch_2"
    entity_id: !input switch_2
    trigger: state

conditions:
  # Prevents infinite loops by ensuring the trigger wasn't caused by this automation itself
  - condition: template
    value_template: "{{ trigger.to_state.context.parent_id != this.context.id }}"
  - condition: template
    value_template: "{{ trigger.to_state.state in ['on','off'] }}"

actions:
  - choose:
      # --- TRIGGERED BY SWITCH 1 ---
      - conditions:
          - condition: template
            value_template: "{{ trigger.id == 'switch_1' }}"
        sequence:
          - if:
              - condition: template
                value_template: "{{ states(switch_2_entity) != trigger.to_state.state }}"
            then:
              - target:
                  entity_id: !input switch_2
                action: switch.turn_{{ trigger.to_state.state }}
                
      # --- TRIGGERED BY SWITCH 2 ---
      - conditions:
          - condition: template
            value_template: "{{ trigger.id == 'switch_2' }}"
        sequence:
          - if:
              - condition: template
                value_template: "{{ states(switch_1_entity) != trigger.to_state.state }}"
            then:
              - target:
                  entity_id: !input switch_1
                action: switch.turn_{{ trigger.to_state.state }}