A Serilog sink for sending log events via Signal messenger. Built on top of Serilog.Sinks.Http.

Package: Serilog.Sinks.Signal

Supported Platforms:

• .NET 4.6.1
• .NET Standard 2.0
• .NET Standard 2.1

• Prerequisites
• Signal CLI REST API Setup
• Installation
• Configuration
• Log Output Format

To send Signal messages, you need to set up a Signal API endpoint. We recommend using the Dockerized Signal Messenger REST API.

Clone the Signal CLI REST API repository:

git clone https://github.com/bbernhard/signal-cli-rest-api.git

Navigate to the project directory and start the Docker container:

docker compose up -d

The API will be available at http://localhost:8080

Step 1: Navigate to the QR code link page in your browser:

http://localhost:8080/v1/qrcodelink?device_name=signal-api

Step 2: A QR code will appear on the screen

Step 3: Open the Signal app on your phone (using the number you want as sender)

Step 4: In Signal, tap:

• Options (top right) → Settings → Linked devices → Link new device

Step 5: Scan the QR code displayed in your browser

Step 6: Your Signal account is now linked and ready to use

Verify the setup by sending a test message:

Windows (Command Prompt):

curl -X POST -H "Content-Type: application/json" "http://localhost:8080/v2/send" -d "{\"message\": \"Test via Signal API!\", \"number\": \"+41000000000\", \"recipients\": [\"+41111111111\"]}"

Linux/Mac:

curl -X POST -H "Content-Type: application/json" 'http://localhost:8080/v2/send' \
  -d '{"message": "Test via Signal API!", "number": "+41000000000", "recipients": ["+41111111111"]}'

Expected response:

{"timestamp":"1768766250942"}

Note: Replace +41000000000 with your sender number and +41111111111 with your recipient number. If sender and recipient are the same, you'll receive a "note to self" message.

The result:

Install the package via NuGet Package Manager:

PM> Install-Package Serilog.Sinks.Signal

Or via .NET CLI:

dotnet add package Serilog.Sinks.Signal

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Debug()
    .WriteTo.Signal(
        options: new Options
        {
            SignalSettings = new SignalSettings
            {
                RrequestUri = "http://localhost:8080/v2/send",
                SenderNumber = "+41000000000",
                Recipients = new[] { "+41111111111", "+41222222222" }
            },
            TimeStampInUtc = false,
            TimeFormat = "dd.MM.yyyy hh:mm:ss"
        },
        null,
        restrictedToMinimumLevel: LogEventLevel.Information)
    .CreateLogger();

Log.Information("Hello Serilog Signal");

Using Serilog.Settings.Configuration:

{
  "Serilog": {
    "MinimumLevel": "Information",
    "WriteTo": [
      {
        "Name": "Signal",
        "Args": {
          "options": {
            "SignalSettings": {
              "RrequestUri": "http://localhost:8080/v2/send",
              "SenderNumber": "+41000000000",
              "Recipients": [ "+41111111111", "+41222222222" ]
            },
            "TimeStampInUtc": true,
            "TimeFormat": "dd.MM.yyyy hh:mm:ss"
          },
          "queueLimitBytes": null
        }
      }
    ]
  }
}

The sink batches multiple log events into single requests for efficiency. Log messages appear in Signal with the following format:

Timestamp: 15.01.2023 01:22:36

Level: 🔴Fatal

MessageTemplate:
"Object reference not set to an instance of an object."

RenderedMessage:
"Object reference not set to an instance of an object."

Exception:
"System.NullReferenceException: Object reference not set to an instance of an object.
   at Program.<Main>$(String[] args) in C:\TestProjects\source\code\Test.Store.Api\Program.cs:line 27"

Properties:
MachineName: "Husam"
ProcessId: 5512
ThreadId: 1
ExceptionDetail: [("Type": "System.NullReferenceException"), ("HResult": -2147467261), ("Message": "Object reference not set to an instance of an object."), ("Source": "Test.Store.Api"), ("StackTrace": " at Program.<Main>$(String[] args) in C:\TestProjects\source\code\Test.Store.Api\Program.cs:line 27"), ("TargetSite": "Void <Main>$(System.String[])")]

This project is built on top of Serilog.Sinks.Http by FantasticFiasco.