> ## 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. # Get token approval data > Get approval transaction data for a DEX swap Returns a list of required token approval transactions for the specified route. This endpoint should be polled until an empty approvals list is returned, indicating that all necessary approvals have been granted. Returns either approval transactions or permit signatures depending on token and swap provider support. If the token supports EIP-2612 permits and the swap provider is configured for it, signatures will be returned ## OpenAPI ````yaml https://api-partner.houdiniswap.com/v2/openapi.json post /dex/approve openapi: 3.0.0 info: title: houdiniswap-backend version: 2.1.1 description: Houdiniswap Backend license: name: ISC contact: {} servers: - url: https://api-partner.houdiniswap.com/v2 security: [] paths: /dex/approve: post: tags: - DEX summary: Get token approval data description: >- Get approval transaction data for a DEX swap Returns a list of required token approval transactions for the specified route. This endpoint should be polled until an empty approvals list is returned, indicating that all necessary approvals have been granted. Returns either approval transactions or permit signatures depending on token and swap provider support. If the token supports EIP-2612 permits and the swap provider is configured for it, signatures will be returned operationId: Approve parameters: [] requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/ApproveRequest' responses: '200': description: Success content: application/json: schema: $ref: '#/components/schemas/ApprovalResponse' '422': description: Validation Failed content: application/json: schema: $ref: '#/components/schemas/ValidationError' '500': description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - apiKey: [] components: schemas: ApproveRequest: properties: quoteId: type: string description: Quote ID from a prior quote response. example: 69a02882f48d56c923119d95 addressFrom: type: string description: Address from which the amount will be deducted (EVM or Tron) example: '0xb7dE6b6eEBF7401aFea5a49D6405C9048fEf2d40' pattern: ^(0x[0-9a-fA-F]{40}|T[1-9A-HJ-NP-Za-km-z]{33})$ usePermit: type: boolean description: >- Whether to use permit instead of approve. Defaults to true for swaps that support it. example: false required: - quoteId - addressFrom type: object additionalProperties: false ApprovalResponse: properties: approvals: items: $ref: '#/components/schemas/ApproveTransaction' type: array signatures: items: $ref: '#/components/schemas/ApprovalTypedData' type: array required: - approvals - signatures 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 ErrorResponse: properties: message: type: string code: type: string requestId: type: string required: - message - code type: object additionalProperties: false ApproveTransaction: properties: data: type: string to: type: string from: type: string fromChain: $ref: '#/components/schemas/Chain' required: - data - to - from - fromChain type: object additionalProperties: false ApprovalTypedData: properties: data: $ref: '#/components/schemas/EIP712TypedData' type: $ref: '#/components/schemas/SignatureType' totalSteps: type: number format: double step: type: number format: double isComplete: type: boolean key: type: string swapRequiredMetadata: $ref: '#/components/schemas/Record_string.any_' required: - data - type - totalSteps - step - isComplete - key type: object additionalProperties: false FieldErrors: properties: {} type: object additionalProperties: properties: value: {} message: type: string required: - message type: object Chain: properties: icon: type: string addressValidation: type: string tokenAddressValidation: type: string id: type: string created: type: string format: date-time modified: type: string format: date-time name: type: string shortName: type: string memoNeeded: type: boolean nullable: true hashUrl: type: string explorerUrl: type: string addressUrl: type: string priority: type: number format: double kind: type: string chainId: type: number format: double nullable: true enabled: type: boolean shortNameV1: type: string required: - icon - addressValidation - tokenAddressValidation - id - created - name - shortName - explorerUrl - addressUrl - kind - enabled - shortNameV1 type: object additionalProperties: false EIP712TypedData: properties: domain: $ref: '#/components/schemas/TypedDataDomain' types: $ref: '#/components/schemas/Record_string.TypedDataField-Array_' primaryType: type: string message: $ref: '#/components/schemas/Record_string.any_' required: - domain - types - primaryType - message type: object additionalProperties: false SignatureType: enum: - single - chained type: string Record_string.any_: properties: {} additionalProperties: {} type: object description: Construct a type with a set of properties K of type T TypedDataDomain: properties: name: type: string version: type: string chainId: type: number format: double verifyingContract: type: string salt: type: string type: object additionalProperties: false Record_string.TypedDataField-Array_: properties: {} additionalProperties: items: $ref: '#/components/schemas/TypedDataField' type: array type: object description: Construct a type with a set of properties K of type T TypedDataField: properties: name: type: string type: type: string required: - name - type type: object additionalProperties: false securitySchemes: apiKey: type: apiKey name: Authorization in: header ````