# Source IP addresses

If your webhook receiving endpoint is behind a firewall or NAT, you may need to allow traffic from the IP addresses listed below. 

{% hint style="info" %}
Please note that these IP addresses may change due to platform maintenance, upgrades, or vendor outage mitigation.
{% endhint %}

## Sandbox

Webhook messages for the API URL `https://api.sandbox.txn.io` are sent from the following IP addresses:

```
52.215.16.239
54.216.8.72
63.33.109.123
2a05:d028:17:8000::/52
```

## Production

Webhook messages for the API URL `https://api.txn.io` are sent from the following IP addresses:

```
44.228.126.217
50.112.21.217
52.24.126.164
54.148.139.208
2600:1f24:64:8000::/52
```