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

# Sponsor a wind-down transaction's fee for a reserve-locked account.



## OpenAPI

````yaml /api-reference/openapi.json post /{network}/fee-bump/sponsor
openapi: 3.0.0
info:
  title: LumenWipe API
  description: Programmatic close-out of Stellar accounts.
  version: 0.1.0
  contact: {}
servers:
  - url: https://api.lumenwipe.com
security: []
tags:
  - name: close
    description: Build and submit an account close-out
  - name: account
    description: Read account state and conversion paths
  - name: mediator
    description: Exchange-destination forwarding
  - name: health
    description: Service health
  - name: service
    description: Service index
  - name: admin
    description: Operator-only self-serve API key management
paths:
  /{network}/fee-bump/sponsor:
    post:
      tags:
        - fee-bump
      summary: Sponsor a wind-down transaction's fee for a reserve-locked account.
      operationId: FeeBumpController_sponsor
      parameters:
        - name: network
          required: true
          in: path
          schema:
            enum:
              - testnet
              - mainnet
            type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/FeeBumpRequestDto'
      responses:
        '200':
          description: >-
            The transaction wrapped in a fee-bump envelope and signed (base64
            XDR).
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FeeBumpSponsorResponseDto'
        '400':
          description: Missing/invalid transaction or disallowed structure.
        '401':
          description: Missing or invalid API key.
        '429':
          description: Rate limit exceeded for this key.
        '503':
          description: Sponsored-fee flow not configured on this server.
      security:
        - api-key: []
components:
  schemas:
    FeeBumpRequestDto:
      type: object
      properties:
        transaction:
          type: string
          description: >-
            The unsigned or user-signed wind-down transaction to sponsor (base64
            XDR), inner fee set to zero.
          example: AAAAAgAAAAB...
      required:
        - transaction
    FeeBumpSponsorResponseDto:
      type: object
      properties:
        transaction:
          type: string
          description: >-
            The fee-bumped transaction envelope (base64 XDR), signed by the
            sponsor.
          example: AAAABQAAAAB...
      required:
        - transaction
  securitySchemes:
    api-key:
      scheme: bearer
      bearerFormat: opaque
      type: http
      description: Integrator API key

````

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