Exposing the MCP server as an SSE endpoint

Shahzad_Ismail — Thu, 19 Jun 2025 15:05:42 GMT

If you want to use the MCP server in hosted environments, you need to access it via a publicly accessible URL. To do this, you need to expose the MCP server as an SSE endpoint, then use a reverse proxy such as NGROK to expose this SSE endpoint via a public URL.

You can then run the MCP server on a remote machine and connect to it using Server-Sent Events (SSE). This is useful if you want to run the MCP server on a cloud server or a dedicated machine. By default, Claude Desktop will connect to the MCP server using STDIO; we will use the supergateway library to connect to the MCP server using SSE.

To expose the MCP server as an SSE endpoint, follow the steps below:

Go to https://github.com/sinch/sinch-mcp-server/blob/main/README.md, go over the pre-requisites such as node.js version greater than 19, npm version greater than 9. Clone the Sinch MCP toolkit repository:
```
git clone https://github.com/sinch/sinch-mcp-server.git
```

Navigate to the mcp directory and build the MCP server:
```
cd sinch-mcp-server
npm install
npm run build
```

Copy the file .template.env and rename it .env. Then replace the placeholders with your own credentials and delete any key you don't need. If .env file is not available, create it. The .env file should look like this ():

# Conversation tools related environment variables
CONVERSATION_PROJECT_ID=
CONVERSATION_KEY_ID=
CONVERSATION_KEY_SECRET=
## Optional but recommended: the App ID holding your channels integration configuration. If not set it must be present in the prompt
CONVERSATION_APP_ID=
## Optional, defaults to "us". Other possible values are "eu" and "br"
CONVERSATION_REGION=
## Needed only if you want to send SMS messages: it is the number that will be used as the sender for SMS messages
DEFAULT_SMS_ORIGINATOR=
## Needed only if you want to send location messages: it converts an address to a latitude/longitude pair
GEOCODING_API_KEY=

# Verification tools related environment variables
VERIFICATION_APPLICATION_KEY=
VERIFICATION_APPLICATION_SECRET=

# Voice tools related environment variables (Application key and secret can be the same as for Verification)
VOICE_APPLICATION_KEY=
VOICE_APPLICATION_SECRET=
## Needed only if you want to make calls: it is the number that will be displayed to the user when they receive a call
CALLING_LINE_IDENTIFICATION=

# Mailgun tools related environment variables
MAILGUN_DOMAIN=
MAILGUN_API_KEY=
MAILGUN_SENDER_ADDRESS=

Start the MCP server:

npm run start

By default, this command will start the MCP with all the tools available. If you want to filter the tools that are available in the MCP server, you can use the --tags option.
For example, if you want to only use the conversation tools, you can modify the command as follows:

# Original command
"start": "tsc && (npx -y supergateway --stdio \"node dist/index.js\" --port 8000 --baseUrl http://localhost:8000 --ssePath /sse --messagePath /message)"

# Modified command to only use conversation tools
"start": "tsc && (npx -y supergateway --stdio \"node dist/index.js --tag conversation\" --port 8000 --baseUrl http://localhost:8000 --ssePath /sse --messagePath /message)"

You can combine multiple tags by separating them with commas. For example, if you want to use both conversation and verification tools, you can use the following command:

"start": "tsc && (npx -y supergateway --stdio \"node dist/index.js --tag conversation,verification\" --port 8000 --baseUrl http://localhost:8000 --ssePath /sse --messagePath /message)"

Configure the MCP server in Claude Desktop. You can then configure the MCP server in the Claude configuration file claude_desktop_config.json with the following script as follows:
```
{
  "mcpServers": {
    "sinch": {
      "command": "npx",
      "args": [
        "-y", "supergateway", "--sse", "http://localhost:8000/sse"
      ]
    }
  }
}
```
Note: Replace the http://localhost:8000/sse with the URL of your MCP server if it is not running locally.

Save the file.

If Claude desktop is open, close it, and restart it. It will now use the latest config file. Create a new chat, click on the 'Search and Tools' icon next to the + icon and you should see the tools from Sinch listed. Now you can use search queries like "list all my apps" or "lookup my number" or "send SMS" and those queries will start using the Sinch tools.

What's next

Hope that helped you set up the Sinch MCP server - please give it a whirl.

If you have any questions or feedback, please share them in our Developer Forum.

We plan to release more updates about the Sinch MCP server and how we participate in the Agentic AI experience, stay tuned!

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Exposing the MCP server as an SSE endpoint

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