Connectors

A connector tells an outside system that something has happened in Highlighter. When a workflow event occurs — a case is completed, an assessment is finalised, files are imported — every connector subscribed to that event sends a notification.

Each connector combines two choices:

Notification types — how the message is delivered: an HTTP request, an email, or a Slack message. A connector can use more than one at once.
Subscribed events — what the connector reacts to.

Connectors are listed under Act → Connectors.

Creating a Connector

Go to Connectors and click New Connector.
Tick one or more Notification Types. Each one reveals only the fields it needs.
Tick the Subscribed Events the connector should react to.
Click Save Connector.

HTTP Request

Sends the event to a URL of your choosing.

URL — where the request is sent.
Authentication — None, or Bearer token to send an Authorization: Bearer … header.
Bearer Token — the token itself. It is stored encrypted and is never shown again. Leave the field blank when editing to keep the existing token.

When authentication is set, the URL must use https, so the token is not sent in clear text. There is no exemption for local addresses — to test against a local endpoint, leave Authentication on None.

Changing the URL of a connector that stores a token requires you to re-enter the token, so a credential issued for one destination is never sent to another.

The request is a POST with a JSON body and Content-Type: application/json:

{
  "event": "project_file_completed",
  "payload": {
    "case_id": 123,
    "project_id": 4
  }
}

The event field names the subscribed event that fired. The contents of payload vary by event.

Email

Sends the event as an email.

Email Settings — a JSON object configuring the message. Recognised keys are email_address, email_subject, email_message, email_content_type, include_image, include_annotations, include_image_metadata, format_image_metadata, and include_image_link.
Annotations To Attach — when annotations are included, restricts the attached annotation crops to the object classes you choose. Leave it empty to attach all of them.

An email with no address, subject, or message is not sent.

Slack

Posts the event to a Slack channel.

Slack Provider — the connected Slack workspace. If none is listed, use the Connect a Slack workspace link to authorise one.
Slack Channel — the destination channel, searchable once a provider is selected.

Subscribed Events

A connector can subscribe to any combination of the following:

Event	Fires when
Manually Triggerable	You trigger the connector yourself, rather than automatically
File Created	A file is added
Assessment Finalised	An assessment is submitted as final
Data Source Files Imported	A data source finishes importing files
Human File Assessment End of Queue	An assessor reaches the end of a queue
Tasks Added To Machine Assessment Step	Tasks are queued for a machine assessment step
Finished Tasks In Machine Assessment Step	Every task in a machine assessment step has finished
Train Requested For Training Run	Training is requested
Cancel Requested For Training Run	Training is cancelled
File Completed in Workflow	A case completes its workflow
Cloud Agent Crash Loop Detected	A cloud agent repeatedly crashes
Case Message Created	A message is added to a case

Narrowing an Event

Three events accept a filter, shown directly beneath the event once you tick it. Leave a filter empty to react to everything.

Assessment Finalised — Only these object classes. The connector fires only when the assessment contains an annotation of one of the chosen classes.
Tasks Added To Machine Assessment Step — Only these steps.
Finished Tasks In Machine Assessment Step — Only these steps.

Each filter applies to every notification type the connector uses.

Testing a Connector

The connector page has a Send Test Notification button. It sends a dummy payload through every notification type the connector has enabled and reports the result immediately, so you can confirm a URL, token, or Slack channel without waiting for a real event.

The test leaves no trace: its events are removed afterwards and do not appear in the connector's history or its counts. A test that fails is not retried — the error is reported to you instead.

Checking Deliveries

Each connector page shows four counts:

Pending — created but not yet delivered. Normally brief; a figure that does not fall means notifications are being generated but nothing is delivering them.
Accepted — delivered successfully.
Retrying — delivery failed and another attempt is scheduled.
Failed — delivery failed and will not be attempted again.

Beneath them, the Events table lists each delivery, newest first, showing when it happened, which event fired, how it was sent, its status, how many attempts have been made, and either the error returned or the identifier the receiving service gave back.

When Highlighter Retries

A failure that might succeed later is retried; one that cannot is not.

HTTP Request — a 5xx response, 429 Too Many Requests or 408 Request Timeout is retried, as are client-side timeouts and connection failures. Any other 4xx, such as 404 Not Found or 403 Forbidden, is treated as a configuration problem and is not retried.
Email — a busy or unreachable mail server is retried. Other failures are not.
Slack — rate limiting and Slack server errors are retried. Other errors, such as an unknown channel, are not. An authentication failure also marks the Slack workspace as needing attention.

Retries back off progressively, from a few seconds to several hours, over a maximum of 15 attempts across roughly two days. After that the notification is marked Failed.

Notifications you trigger yourself, including the test button, are delivered immediately rather than queued, so they are never retried.