A basic YAML config for the Shelly 1, equipped with everything necessary to use it.

shelly1_v3.yaml

---
# Shelly 1 - ESPHome yaml config
substitutions:
  device_name: shelly-1
  friendly_name: Shelly 1
  project_version: "1.0.0"
  
  # Define GPIO pins
  relay_pin: GPIO4
  switch_pin: GPIO5

esphome:
  name: '${device_name}'
  name_add_mac_suffix: true
  project:
    name: "klaasnicolaas.shelly-1"
    version: "${project_version}"

esp8266:
  board: esp01_1m

wifi:
  ap:
    ssid: '${friendly_name}'

logger:
api:

# Allow OTA updates
ota:
  safe_mode: true
  reboot_timeout: 10min
  num_attempts: 5

# Allow provisioning Wi-Fi via serial
improv_serial:

# In combination with the `ap` this allows the user
# to provision wifi credentials to the device via WiFi AP.
captive_portal:

# To have a "next url" for improv serial
web_server:

# Output
output:
  - platform: gpio
    pin: ${relay_pin}
    id: shelly_1_relay

# Button
button:
  # Restart the ESP
  - platform: restart
    name: '${friendly_name} - Restart'

# Text sensor
text_sensor:
  # ESPHome version
  - platform: version
    hide_timestamp: true
    name: '${friendly_name} - ESPHome Version'
  # IP address and connected SSID
  - platform: wifi_info
    ip_address:
      name: '${friendly_name} - IP Address'
      icon: mdi:wifi
    ssid:
      name: '${friendly_name} - Connected SSID'
      icon: mdi:wifi-strength-2

# Light
light:
  - platform: binary
    name: '${friendly_name} - Light'
    output: shelly_1_relay
    id: light_id

# Binary sensor
binary_sensor:
  - platform: gpio
    pin:
      number: ${switch_pin}
      #mode: INPUT_PULLUP
      #inverted: True
    name: '${friendly_name} - Switch'
    on_state:
      then:
        - light.toggle: light_id
    internal: true
    id: switch_id