SIGNL4

Send and resolve mobile alerts via SIGNL4 with optional file attachments

Overview

The SIGNL4 tool sends new alerts and resolves existing alerts via the SIGNL4 webhook API (POST https://connect.signl4.com/webhook/{teamSecret}). The “send” operation creates a new alert with a message, optional title, service category, alerting scenario (single_ack or multi_ack), external correlation ID, location coordinates, keyword filtering, and an optional binary file attachment (PNG, JPG, BMP, GIF, MP3, WAV). The “resolve” operation closes a previously sent alert by its external ID. All requests use multipart/form-data. Authentication uses a team secret embedded in the webhook URL path.

Category: Communication
Tool Name: signl4
Version: 1

Appearance: Icon: lucide-Siren | Color: #0080FF

Node Type

Action (Binary) — handles file/binary data operations

Input / Output

Direction	Port(s)
Input	Input
Output	Output, Error

Credentials

This tool requires SIGNL4 Webhook credentials. See the Credentials Guide for setup instructions.

Resources

Resource	Value
Alert	alert

Operations

Operation	Value	Description
Alert: Send	send	Send a new alert
Alert: Resolve	resolve	Resolve an existing alert

Parameters

Alert: Send

Parameter	Type	Required	Default	Description
Message	string	Yes	—	A more detailed description for the alert. Supports expressions.
Additional Fields	collection	No	{}	Optional fields to send alongside the alert.
— Alerting Scenario	options	No	single_ack	Determines how many people need to acknowledge this alert.
				Options: single_ack (only one person needs to confirm the alert), multi_ack (all on-duty team members must confirm the alert)
— Attachment (Binary Property)	string	No	—	Name of the binary property containing a file to attach to the alert. Supported formats: PNG, JPG, JPEG, BMP, GIF, MP3, WAV. Leave empty for no attachment. Names are case-sensitive — see the upstream node’s Binary Data panel for the exact names to use.
— External ID	string	No	—	If the event originates from a record in a 3rd party system, pass the unique ID of that record. This ID will be communicated in outbound webhook notifications from SIGNL4. Use the same External ID to resolve the alert later. Supports expressions.
— Filtering	boolean	No	false	Whether to apply event filtering. If true, the event only triggers a notification if it contains at least one keyword from your services and system categories (whitelisted).
— Latitude	string	No	—	Latitude for geo-location display. Must be provided together with Longitude. Supports expressions.
— Longitude	string	No	—	Longitude for geo-location display. Must be provided together with Latitude. Supports expressions.
— Service	string	No	—	Assigns the alert to the service/system category with the specified name. Supports expressions.
— Title	string	No	—	The title or subject of this alert. Supports expressions.

Alert: Resolve

Parameter	Type	Required	Default	Description
External ID	string	Yes	—	The external ID that was used when the alert was originally sent. Must match exactly to resolve the correct alert. Supports expressions.

All Operations

Parameter	Type	Required	Default	Description
Max Concurrency	number	No	5	Maximum number of items to process concurrently. Keep low for alerting systems to avoid flooding.

Output Data

One output item is produced per input item, on the Output port, for both send and resolve. SIGNL4’s JSON response — its acknowledgement of the alert, which identifies the event it recorded — is merged onto the item JSON at the top level rather than nested under a wrapper property, so the rest of the incoming item passes through unchanged and response fields are addressed directly by expression. Binary data on the input item is forwarded untouched, including the property you attached to the alert. Neither operation fans out.

A non-2xx reply from the webhook raises an item error carrying the HTTP status and the body SIGNL4 returned. Failures go to the Error port in errorPort mode, carrying _error.

Usage Examples

• Send a critical alert when server CPU exceeds threshold
• Resolve an existing alert by its external ID
• Send an alert with a screenshot image attached
• Send an alert with geo-location coordinates
• Send an alert with multi-ack requiring all on-duty team members to confirm

Example Configuration

Raise a plain alert from a monitoring item:

{
  "type": "signl4",
  "parameters": {
    "resource": "alert",
    "operation": "send",
    "message": "Server CPU usage exceeded 90% threshold on {{ $json.host }}"
  }
}

Add a title, route the alert to a service category, and give it a correlation ID you can resolve on later:

{
  "type": "signl4",
  "parameters": {
    "resource": "alert",
    "operation": "send",
    "message": "Database connection pool exhausted - immediate attention required",
    "additionalFields": {
      "title": "Critical Database Alert",
      "service": "database-cluster",
      "externalId": "db-alert-{{ $json.incidentId }}",
      "alertingScenario": "single_ack",
      "filtering": true
    }
  }
}

Attach a screenshot held in the item’s data binary property:

{
  "type": "signl4",
  "parameters": {
    "resource": "alert",
    "operation": "send",
    "message": "Dashboard shows a sustained error spike - screenshot attached",
    "additionalFields": {
      "title": "Error Rate Spike",
      "service": "web-application",
      "binaryPropertyName": "data",
      "externalId": "err-spike-{{ $json.runId }}"
    }
  }
}

Put the alert on the map and require every on-duty responder to acknowledge it:

{
  "type": "signl4",
  "parameters": {
    "resource": "alert",
    "operation": "send",
    "message": "Fire alarm triggered in data center - evacuation protocol initiated",
    "additionalFields": {
      "title": "EMERGENCY: Fire Alarm Activated",
      "service": "facility-management",
      "externalId": "fire-alarm-dc1",
      "latitude": "40.7128",
      "longitude": "-74.0060",
      "alertingScenario": "multi_ack"
    }
  }
}

Close an alert once the underlying condition clears:

{
  "type": "signl4",
  "parameters": {
    "resource": "alert",
    "operation": "resolve",
    "externalId": "{{ $json.externalId }}"
  }
}

Error Handling

Mode	Behavior
stop	Halts workflow on first error
continue	Skips failed items, passes successful ones through
errorPort	Routes failed items to Error output port

Tips

Send new alerts or resolve existing alerts via the SIGNL4 mobile alerting platform, with optional file attachments.

Notes

• Resolving matches on External ID alone, so an alert can only be closed from a workflow if you set an External ID in Additional Fields when you sent it. Use a value you can reproduce later, such as an ID carried on the item.
• Latitude and Longitude only take effect as a pair. If either is empty, no location is attached to the alert.
• The attachment is sent only when the item actually carries a binary property under the name you gave. If it does, the file extension must be one of png, jpg, jpeg, bmp, gif, mp3 or wav — anything else fails the item.
• Keep Max Concurrency low. Each item is a separate alert, and a burst of them reaches every on-duty phone at once.