> ## Documentation Index
> Fetch the complete documentation index at: https://docs.leanmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Create a new subdomain mapping (API Key)



## OpenAPI

````yaml post /api/lambda-mapping
openapi: 3.0.0
info:
  title: LeanMCP SDK API
  description: >-
    API endpoints for LeanMCP SDK integration. These endpoints use API key
    authentication and are designed for programmatic access from the CLI and
    SDK.
  version: 1.0.0
servers:
  - url: https://api.leanmcp.com
    description: Production
  - url: http://localhost:3001
    description: Local Development
security: []
tags:
  - name: builds-sdk
  - name: chat-messages-api-key
  - name: chats-api-key
  - name: deployments-api-key
  - name: deployments-sdk
  - name: mapping-sdk
  - name: projects-api-key
paths:
  /api/lambda-mapping:
    post:
      tags:
        - mapping-sdk
      summary: Create a new subdomain mapping (API Key)
      operationId: LambdaMappingApiKeyController_createMapping
      parameters: []
      responses:
        '201':
          description: Mapping created successfully
        '409':
          description: Subdomain already exists
      security:
        - ApiKeyAuth: []
components:
  securitySchemes:
    ApiKeyAuth:
      type: http
      scheme: bearer
      bearerFormat: API Key
      description: Enter your LeanMCP API key

````