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

# Submit signed EVM UserOperation(s)

> Submit signed EVM UserOperation(s) to the bundler.
Pass one signature per batch in the same order as returned by POST multi/{multiId}/tx/build.
Most multi-swaps produce a single batch, so typically only one signature is needed.



## OpenAPI

````yaml https://api-partner.houdiniswap.com/v2/openapi.json post /exchanges/multi/{multiId}/tx
openapi: 3.0.0
info:
  title: houdiniswap-backend
  version: 2.1.2
  description: Houdiniswap Backend
  license:
    name: ISC
  contact: {}
servers:
  - url: https://api-partner.houdiniswap.com/v2
security: []
paths:
  /exchanges/multi/{multiId}/tx:
    post:
      tags:
        - Exchanges
      summary: Submit signed EVM UserOperation(s)
      description: >-
        Submit signed EVM UserOperation(s) to the bundler.

        Pass one signature per batch in the same order as returned by POST
        multi/{multiId}/tx/build.

        Most multi-swaps produce a single batch, so typically only one signature
        is needed.
      operationId: SubmitMultiExchangeTx
      parameters:
        - in: path
          name: multiId
          required: true
          schema:
            type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SubmitEvmBatchTxRequest'
      responses:
        '200':
          description: UserOperation(s) submitted
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SubmitEvmBatchTxResult'
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '422':
          description: Validation Failed
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ValidationError'
        '500':
          description: Internal Server Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
      security:
        - apiKey: []
components:
  schemas:
    SubmitEvmBatchTxRequest:
      properties:
        signatures:
          items:
            type: string
          type: array
          description: >-
            One signature per batch, in the same order as the build response
            transactions array
      required:
        - signatures
      type: object
      additionalProperties: false
    SubmitEvmBatchTxResult:
      properties:
        userOpHashes:
          items:
            type: string
          type: array
          description: >-
            ERC-4337 UserOperation hash(es) returned by the bundler — one per
            batch
      required:
        - userOpHashes
      type: object
      additionalProperties: false
    ErrorResponse:
      properties:
        message:
          type: string
        code:
          type: string
        requestId:
          type: string
      required:
        - message
        - code
      type: object
      additionalProperties: false
    ValidationError:
      properties:
        message:
          type: string
        code:
          type: string
        requestId:
          type: string
        fields:
          $ref: '#/components/schemas/FieldErrors'
      required:
        - message
        - code
        - fields
      type: object
      additionalProperties: false
    FieldErrors:
      properties: {}
      type: object
      additionalProperties:
        properties:
          value: {}
          message:
            type: string
        required:
          - message
        type: object
  securitySchemes:
    apiKey:
      type: apiKey
      name: Authorization
      in: header

````