> ## Documentation Index > Fetch the complete documentation index at: https://docs.lite.sa/llms.txt > Use this file to discover all available pages before exploring further. # Get an authentication session > Retrieves a 3DS authentication session using the provided authentication id ## OpenAPI ````yaml /openapi/payment-acceptance.json get /threeds/authentications/{authentication_id} openapi: 3.1.0 info: title: lite - Payment Acceptance version: 1.0.0 servers: - url: https://api.lite.sa/v1 description: Production security: - ApiKeyAuth: [] - BearerAuth: [] tags: - name: 3DS Authentication description: Standalone payer authentication via the 3DS standard - name: Hosted Checkout description: Create, manage and deploy hosted checkout pages - name: Server-to-Server Payments description: Direct payment API for server-side integrations paths: /threeds/authentications/{authentication_id}: get: tags: - 3DS Authentication summary: Get an authentication session description: > Retrieves a 3DS authentication session using the provided authentication id operationId: lite.3ds.getAuthentication parameters: - $ref: '#/components/parameters/authentication_id' - $ref: '#/components/parameters/x-correlation-id' responses: '200': $ref: '#/components/responses/AuthenticationResponse' '401': $ref: '#/components/responses/Unauthorized' '404': $ref: '#/components/responses/NotFound' components: parameters: authentication_id: name: authentication_id in: path required: true description: Unique identifier of the authentication session schema: type: string format: uuid example: 9822ffb8-26de-423b-ad15-0d129cf1b4ac x-correlation-id: name: x-correlation-id in: header required: false description: >- Unique identifier for request tracing. Generated by the client or server if not provided. schema: type: string format: uuid example: 550e8400-e29b-41d4-a716-446655440000 responses: AuthenticationResponse: description: Authentication session retrieved. content: application/json: schema: $ref: '#/components/schemas/AuthenticationSession' Unauthorized: description: | Authentication failed — missing or invalid token. Returned when: - The JWT bearer token is missing, expired, or has an invalid signature - The API key is missing or invalid - The authenticated session token is invalid content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NotFound: description: | The requested resource was not found. Returned when: - The specified resource ID does not exist - The path does not match any known endpoint content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' schemas: AuthenticationSession: type: object required: - id - merchant_id - instrument_id - status properties: id: type: string format: uuid description: Unique 3DS authentication ID example: baf6a8e2-0c89-46ef-9ca5-faa65b99bcd5 merchant_id: type: string format: uuid description: Merchant ID example: a1b2c3d4-e5f6-7890-abcd-ef1234567890 instrument_id: type: string format: uuid description: Instrument ID example: baf6a8e2-0c89-46ef-9ca5-faa65b99bcd5 status: type: string description: 3DS authentication status example: AUTHENTICATED oneOf: - title: Pending const: PENDING description: >- Authentication session has been created and is awaiting processing - title: Challenge Required const: CHALLENGE_REQUIRED description: Cardholder must complete a 3DS challenge for authentication - title: Authenticated const: AUTHENTICATED description: Cardholder was successfully authenticated - title: Expired const: EXPIRED description: Authentication session expired before completion - title: Failed const: FAILED description: Authentication failed or was rejected authentication_value: type: string description: Authentication value (CAVV) example: AAABBJkZUgAAAAAAAAAAAAAAAAA= eci: type: string minLength: 2 maxLength: 2 description: Electronic Commerce Indicator example: '05' xid: type: string minLength: 1 maxLength: 100 description: Transaction identifier (XID) example: abc123xyz version: type: string pattern: ^\d+\.\d+\.\d+$ description: 3DS protocol version example: 2.1.0 threeds_server_trans_id: type: string description: 3DS Server transaction ID example: threeds_a1b2c3d4e5f6 ds_transaction_id: type: string description: Directory Server transaction ID example: dstxn_a1b2c3d4e5f6 acs_transaction_id: type: string description: ACS transaction ID example: acstxn_a1b2c3d4e5f6 acs_reference_number: type: string minLength: 1 maxLength: 32 description: ACS reference number example: ELAVON_ACS_EMULATOR_REF_NUMBER32 ds_reference_number: type: string minLength: 1 maxLength: 32 description: Directory Server reference number example: ELAVON_3DS_DS_EMULATOR_REF_NUM32 acs_operator_id: type: string minLength: 1 maxLength: 32 description: ACS operator ID example: ELAVON_ACS_EMULATOR_OPERATOR_ID1 acs_challenge_mandated: type: string description: Whether a challenge is required example: 'Y' oneOf: - title: 'Yes' const: 'Y' description: Challenge is mandated - title: 'No' const: 'N' description: Challenge is not mandated acs_authentication_type: type: string minLength: 2 maxLength: 10 description: ACS authentication type code example: '01' acs_challenge_cancel_reason: type: string description: Challenge cancel reason code example: '01' trans_status: type: string pattern: ^[A-Z]$ description: Transaction status code example: C trans_status_reason: type: string description: Transaction status reason example: '01' return_url: type: string description: Return URL for 3DS challenge example: https://example.com/threeds/callback ErrorResponse: type: object required: - error properties: error: type: object required: - code - message - timestamp properties: code: type: string description: Error code identifying the type of error example: PAYMENT_DETAILS_MISMATCH message: type: string description: Human-readable error description example: The request was invalid or malformed details: type: object description: Additional error details correlationId: type: string format: uuid description: Correlation ID for tracking the request example: 550e8400-e29b-41d4-a716-446655440000 timestamp: type: string format: date-time description: Timestamp when the error occurred example: '2024-12-16T10:30:00.000Z' securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: API key for service-to-service or merchant authentication. BearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- JWT Bearer token obtained from user authentication. Passed as Authorization: Bearer . ````