diff --git a/monster-card.js b/monster-card.js
new file mode 100644
index 0000000..3964b09
--- /dev/null
+++ b/monster-card.js
@@ -0,0 +1,122 @@
+class MonsterCard extends HTMLElement {
+
+  _getEntities(hass, filters) {
+    function _filterEntityId(stateObj, pattern) {
+      if (pattern.indexOf('*') === -1) {
+        return stateObj.entity_id === pattern;
+      }
+      const regEx = new RegExp(`^${pattern.replace(/\*/g, '.*')}$`, 'i');
+      return stateObj.entity_id.search(regEx) === 0;
+    }
+    function _filterName(stateObj, pattern) {
+      let compareEntity = stateObj.attributes.title ? stateObj.attributes.title : stateObj.attributes.friendly_name;
+      if (!compareEntity) compareEntity = stateObj.entity_id;
+      if (pattern.indexOf('*') === -1) {
+        return compareEntity === pattern;
+      }
+      const regEx = new RegExp(`^${pattern.replace(/\*/g, '.*')}$`, 'i');
+      return compareEntity.search(regEx) === 0;
+    }
+    // Allows '< 300' in b
+    function _complexCompare(a, b) {
+      const _compare = {
+        '>': (x, y) => x > y,
+        '<': (x, y) => x < y,
+        '<=': (x, y) => x <= y,
+        '>=': (x, y) => x >= y,
+        '=': (x, y) => x === y,
+      };
+      let operator = '=';
+      let y = b;
+      let x = a;
+      if (!isNaN(a) && typeof (b) == 'string'
+        && b.split(" ").length > 1) {
+        [operator, y] = b.split(' ', 2);
+        x = parseFloat(a);
+      }
+      return _compare[operator](x, y);
+    }
+    const entities = new Map();
+    filters.forEach((filter) => {
+      const filters = [];
+      if (filter.domain) {
+        filters.push(stateObj => stateObj.entity_id.split('.', 1)[0] === filter.domain);
+      }
+      if (filter.attributes) {
+        Object.keys(filter.attributes).forEach(key => {
+          filters.push(stateObj => _complexCompare(stateObj.attributes[key], filter.attributes[key]));
+        });
+      }
+      if (filter.entity_id) {
+        filters.push(stateObj => _filterEntityId(stateObj, filter.entity_id));
+      }
+      if (filter.name) {
+        filters.push(stateObj => _filterName(stateObj, filter.name));
+      }
+      if (filter.state) {
+        filters.push(stateObj => _complexCompare(stateObj.state, filter.state));
+      }
+
+      const options = filter.options ? filter.options : {}
+
+      Object.keys(hass.states).sort().forEach(key => {
+        if (filters.every(filterFunc => filterFunc(hass.states[key]))) {
+          entities.set(hass.states[key].entity_id, Object.assign({ "entity": hass.states[key].entity_id }, options));
+        }
+      });
+    });
+    return Array.from(entities.values());
+  }
+
+  setConfig(config) {
+    if (!config.filter.include || !Array.isArray(config.filter.include)) {
+      throw new Error('Please define filters');
+    }
+
+    if (this.lastChild) this.removeChild(this.lastChild);
+
+    const cardConfig = Object.assign({}, config);
+    if (!cardConfig.card) cardConfig.card = {};
+    if (config.card.entities) delete config.card.entities;
+    if (!cardConfig.card.type) cardConfig.card.type = 'entities';
+
+    const element = document.createElement(`hui-${cardConfig.card.type}-card`);
+    this.appendChild(element);
+
+    this._config = cardConfig;
+  }
+
+  set hass(hass) {
+    const config = this._config;
+    let entities = this._getEntities(hass, config.filter.include);
+    if (config.filter.exclude) {
+      const excludeEntities = this._getEntities(hass, config.filter.exclude).map(entity => entity.entity);
+      entities = entities.filter(entity => !excludeEntities.includes(entity.entity));
+    }
+
+
+
+    if (entities.length === 0 && config.show_empty === false) {
+      this.style.display = 'none';
+    } else {
+      if (config.when && (hass.states[config.when.entity].state == config.when.state) || !config.when) {
+        this.style.display = 'block';
+      } else {
+        this.style.display = 'none';
+      }
+    }
+
+    if (!config.card.entities || config.card.entities.length !== entities.length ||
+      !config.card.entities.every((value, index) => value.entity === entities[index].entity)) {
+      config.card.entities = entities;
+      this.lastChild.setConfig(config.card);
+    }
+    this.lastChild.hass = hass;
+  }
+
+  getCardSize() {
+    return 'getCardSize' in this.lastChild ? this.lastChild.getCardSize() : 1;
+  }
+}
+
+customElements.define('monster-card', MonsterCard);