OpenAPI MCP Server - AWS Lambda Deployment

Serverless deployment of the AWS Labs OpenAPI MCP Server on AWS Lambda with API Gateway.

Overview

This project wraps the awslabs openapi-mcp-server to run as a serverless Lambda function, enabling MCP (Model Context Protocol) clients to interact with OpenAPI-defined APIs through AWS infrastructure.

Architecture

Lambda Function: FastMCP server with HTTP transport (Starlette ASGI)
API Gateway: HTTP API exposing the MCP endpoints
Transport: Mangum ASGI adapter (no child process overhead)

Prerequisites

Python 3.12+
uv package manager
AWS CLI configured
AWS CDK CLI: npm install -g aws-cdk

Local Setup

Install dependencies:

uv sync

Deployment

1. Bootstrap CDK (first time only)

cdk bootstrap

2. Deploy Stack

cd cdk cdk deploy \ --parameters ApiName=MyAPI \ --parameters ApiBaseUrl=https://api.example.com \ --parameters ApiSpecUrl=https://api.example.com/openapi.json \ --parameters AuthType=none

Configuration Parameters

ApiName: Display name for the API
ApiBaseUrl: Base URL of the target API
ApiSpecUrl: URL to the OpenAPI specification (JSON or YAML)
AuthType: Authentication method (none, basic, bearer, api_key, cognito)

Additional Auth Configuration

Set environment variables in cdk/openapi_mcp_stack.py for authentication:

Basic Auth:

AUTH_USERNAME
AUTH_PASSWORD

Bearer Token:

AUTH_TOKEN

API Key:

AUTH_API_KEY
AUTH_API_KEY_NAME
AUTH_API_KEY_IN (header/query/cookie)

Cognito:

AUTH_COGNITO_CLIENT_ID
AUTH_COGNITO_USERNAME
AUTH_COGNITO_PASSWORD
AUTH_COGNITO_USER_POOL_ID
AUTH_COGNITO_REGION

3. Get API URL

After deployment, CDK outputs the API Gateway URL:

# Output example: # OpenApiMcpStack.ApiUrl = https://abc123.execute-api.us-east-1.amazonaws.com/

Testing

Test the deployed Lambda function:

curl -X POST https://<api-url>/message \ -H "Content-Type: application/json" \ -d '{"jsonrpc": "2.0", "method": "tools/list", "id": 1}'

Performance Considerations

Cold Start: ~1-2 seconds (initializes MCP server + loads OpenAPI spec)
Warm Start: ~100-300ms (reuses server instance)
Timeout: 30 seconds (configurable in stack)
Memory: 512 MB (configurable in stack)

Cost Optimization

Requests: Pay per invocation
Memory/Duration: 512 MB x execution time
API Gateway: HTTP API (cheaper than REST API)

Development

Run MCP server locally:

uv run awslabs.openapi-mcp-server \ --api-name MyAPI \ --api-url https://api.example.com \ --spec-url https://api.example.com/openapi.json

Cleanup

cd cdk cdk destroy

License

This project includes code from awslabs/mcp licensed under Apache-2.0. See LICENSE and NOTICE files.

This server cannot be installed

-

security - not tested

-

license - not tested

-

quality - not tested

How are these scores calculated?

Resources

GitHub Repository

Need Help?

Report Issue

Related Servers

Appeared in Searches

InsForge Function Host server or service

OpenAPI Lambda MCP Server