Zulip supports integration with Papertrail as a Webhook that fires upon finding a certain log. To do this:

First, create the stream you'd like to use for Papertrail notifications, and subscribe all interested parties to this stream. We recommend the stream name be papertrail. After create a bot named Papertrail and note the API key.

Next, log into your Papertrail Account and browse through your logs. Search for logs you want to get alerts for and press the Save Search to open up a modal window, then fill out the details and press the Save & Setup an alert button.

Go to the Create an alert section, press the Webhooks link and place the below URL into the Webhook URL section. Be sure to set the frequency to either minute, hour or day.

{{ external_api_uri_subdomain }}/v1/external/papertrail?api_key=abcdefgh&stream=papertrail

Note: api_key is the API key of your Zulip bot, and stream is the stream name you want the notifications sent to.

Congratulations! You're done!
Your Papertrail notifications will appear in Zulip: