LendKey Authentication API

openapi: 3.0.3
info:
  title: LendKey E-Sign API (via Kong Gateway) Application Contracts Authentication API
  version: 0.1
  description: "# LendKey E-Sign API - Kong Gateway Documentation\n\n## Overview\n\nThe LendKey E-Sign API provides endpoints for creating and managing electronic signature contracts using DocuSign.\nThis API is accessed through Kong Gateway, which handles authentication via OAuth2.\n\n## Authentication\n\nAll requests to this API require OAuth2 authentication through Kong Gateway.\n\n### Step 1: Get OAuth2 Token\n\nBefore calling any endpoint, you must obtain an access token:\n\n**Production Environment:**\n```bash\ncurl -X POST https://api.lendkey.com/esign/oauth2/token \\\n  -d \"grant_type=client_credentials\" \\\n  -d \"client_id=YOUR_CLIENT_ID\" \\\n  -d \"client_secret=YOUR_CLIENT_SECRET\"\n```\n\n**Response:**\n```json\n{\n  \"access_token\": \"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...\",\n  \"token_type\": \"bearer\",\n  \"expires_in\": 7200\n}\n```\n\n### Step 2: Use Token in API Calls\n\nInclude the access token in the `Authorization` header:\n```\nAuthorization: Bearer YOUR_ACCESS_TOKEN\n```\n\n**Token Lifetime:** 2 hours (7200 seconds)\n\n## Base URLs (Kong Gateway)\n\n| Environment | Kong Base URL | Backend Kubernetes Service |\n|------------|---------------|---------------------------|\n| **Production** | `https://api.lendkey.com/esign` | `main-esign-kotlin.ci.lkeyprod.com` |\n\n## How Kong Routes Requests\n\nWhen you call Kong:\n```\nhttps://api.lendkey.com/esign/applications\n```\n\nKong:\n1. Validates your OAuth2 token\n2. Strips the `/esign` prefix\n3. Forwards to: `http://main-esign-kotlin.ci.lkeyprod.com/applications`\n\nYou don't need to manage any backend authentication - Kong handles everything!\n\n## Getting Started\n\n1. **Get Credentials:** Contact your Kong admin or use the Kong Developer Portal\n2. **Get Token:** Use the OAuth2 token endpoint for your environment\n3. **Call API:** Use the token in the Authorization header\n4. **Refresh:** Get a new token every 2 hours\n"
  contact:
    name: LendKey Platform Team
    url: https://lendkey.com
servers:
- url: https://api.lendkey.com/esign
  description: Production Environment
security:
- oauth2: []
tags:
- name: Authentication
  description: OAuth2 authentication endpoints
paths:
  /oauth2/token:
    post:
      summary: Get OAuth2 Access Token
      description: 'Obtain an OAuth2 access token for authenticating API requests.

        This endpoint is provided by Kong Gateway.


        **Token expires after 2 hours** - you''ll need to request a new token when it expires.

        '
      tags:
      - Authentication
      operationId: getOAuth2Token
      security: []
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              type: object
              required:
              - grant_type
              - client_id
              - client_secret
              properties:
                grant_type:
                  type: string
                  enum:
                  - client_credentials
                  description: OAuth2 grant type (always "client_credentials")
                client_id:
                  type: string
                  description: Your client ID from Kong Developer Portal
                  example: abc123def456
                client_secret:
                  type: string
                  format: password
                  description: Your client secret from Kong Developer Portal
                  example: xyz789secret123
      responses:
        '200':
          description: Access token successfully generated
          content:
            application/json:
              schema:
                type: object
                properties:
                  access_token:
                    type: string
                    description: JWT access token to use in Authorization header
                    example: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
                  token_type:
                    type: string
                    enum:
                    - bearer
                    description: Token type (always "bearer")
                  expires_in:
                    type: integer
                    description: Token lifetime in seconds (7200 = 2 hours)
                    example: 7200
        '401':
          description: Invalid credentials
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  schemas:
    ErrorResponse:
      type: object
      properties:
        error:
          type: string
          example: Invalid request
        message:
          type: string
          example: Application UUID is required
  securitySchemes:
    oauth2:
      type: oauth2
      description: OAuth2 client credentials flow via Kong Gateway
      flows:
        clientCredentials:
          tokenUrl: /oauth2/token
          scopes: {}