Hi everyone!
I built this integration a while back but never got around to posting it here. Finally doing it. 
It’s already in the HACS default list. Just search **Entity Availability** and install directly, no custom repository URL needed.
## What is it?
**Entity Availability** monitors groups of your Home Assistant devices and answers the questions you keep asking yourself:
- *Is that door sensor actually working, or has it been offline for hours?*
- *Which camera went down last night?*
- *How reliable is my Zigbee network, really?*
- *That motion sensor did stop reporting, or is it just quiet?*
You organize devices into groups (e.g. “Security”, “Climate”, “Media”) and the integration creates sensors for each one. There’s no database dependency, data is stored in its own storage file, so your Home Assistant database stays lean.
## The highlights
**Offline detection**
Detects when a device goes unavailable or unresponsive (or any state you choose). A cooldown period means quick dropouts don’t trigger false alerts.
**Availability %**
Shows what percentage of the time your group of devices was fully online, covering today, over the last 3 days, and the last 7 days.
**MTBF & MTTR**
Two sensors that go deeper than a simple availability percentage:
- *MTBF (Mean Time Between Failures)*: how often does a device fail? A device that drops offline every hour but comes back in seconds might look fine on availability percentage alone but MTBF will flag it.
- *MTTR (Mean Time To Recovery)*: how long does each outage last, on average?
**Battery monitoring**
Auto-detects battery sensors. Sends an alert when a battery drops below your chosen threshold.
**Staleness detection**
Some sensors go quiet without showing as unavailable since they stopped sending updates. Staleness detection catches that.
**Signal strength monitoring** *(optional)*
Link a signal sensor to each device and track Wi-Fi, Zigbee, Z-Wave, Bluetooth, and more. Sends an alert when signal quality drops.
**Non-essential devices**
Mark devices where being offline is expected, like a TV on standby or a printer you only use occasionally. They still appear on the card, but they won’t affect your group’s health score or trigger alerts.
**Combined groups**
Merge multiple groups into one aggregate view. One binary sensor for your whole home.
## The card
Comes with a custom dashboard card:
Works with both regular and combined groups. Has a visual editor, so you don’t need to write any YAML. Options include an expandable device list, availability bars, per-device detail tooltips, suppress buttons, sort order, compact mode, and more.
## Automation examples on the repo
## Links
## Other integrations by me
If you find this useful, I’ve built a few other custom integrations too:
- Entity Guard: Enforces device states using simple rules. Replaces hand-written auto-off, auto-lock, and kill-switch automations.
- Entity Distance: Tracks distance between 2–5 people, devices, or zones, including direction, speed, ETA, and proximity.
- Entity State Tracker: Tracks how long devices spend in each state over time, with per-state breakdowns, scoring, and a custom card.
- Fuel Compare: Tracks live fuel prices from 36 providers across 30 countries.
- WashWise: Helps you decide whether to wash your car, bike, or solar panels, and whether to run garden irrigation, based on the weather forecast.
- DashSnap: Home Assistant App to record or screenshot any web page via headless Chromium: HA dashboards, Grafana, public pages.
- DashSnap Integration: Trigger DashSnap from Home Assistant automations. See App above.
Happy to answer questions here. Bug reports and feature requests are welcome on GitHub Issues too.