# Reachability

Reachability monitoring for your nodes. We run periodic checks and alert you if we're unable to successfully reach your node.

We can alert you on any events impacting reachability of your node and deliver that alert to you through your favorite method. List of supported integrations can be found [here](/readme/integrations.md).

### Reachability checks - how do they work 

You can use any combination of checks for your node,limited only by connectivity options you have - ipv4, ipv6, tor.

**Lightning**

We send a small probe over lightning network to see if your node responds. Checks are run on multiple nodes positioned in different parts of the network to ensure connectivity and prevent false positive alerts.

{% hint style="info" %}
To ensure successful checks, your node should have an inbound liquidity exceeding 100 sats and a minimum HTLC size below 100 sats. 

If you are not sure about your current inbound liquidity level, you have the option to establish workflows that will notify you when your liquidity falls below a specific threshold in [Node and liquidity automation](/readme/liquidops/node-and-liquidity-automation.md)
{% endhint %}

**TCP**

Basic tcp check to see if your node is reachable on port 9735 over internet. Supports ipv4 and ipv6.

**Tor**

Basic tcp check to see if your node is reachable on port 9735 over Tor network.

### Checks performance

#### Builder plan

In the free version, we conduct TCP, TOR, and Lightning Network checks at best effort, and the interval between checks can extend up to 15 minutes.

#### Pro and Business plans

In our Pro and Business plans, specifically designed to meet the needs of more demanding nodes, we offer faster checks at a 60-second interval. A quicker detection enables swifter troubleshooting leading to a better customer experience.


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