> ## Documentation Index > Fetch the complete documentation index at: https://docs.intermezzo.ai/llms.txt > Use this file to discover all available pages before exploring further. # Connect to an existing NEST employer > Connects the organisation to an employer already registered with NEST, by its employer reference. Nothing is created in NEST: the employer's groups and payment sources are read and recorded. The employer must have granted Intermezzo delegate access in NEST. Returns 202 with a submission ID; poll /nest/status for the outcome. ## OpenAPI ````yaml /api-reference/preview.json post /gb/organizations/{organization_id}/pension/nest/link openapi: 3.2.0 info: title: Intermezzo Global Payroll summary: Global Payroll Platform description: Intermezzo's global payroll apis, organized by country version: '2026-10-07' x-logo: url: /static/icon.svg servers: - url: https://preview.intermezzo.ai description: Preview security: [] paths: /gb/organizations/{organization_id}/pension/nest/link: post: tags: - Great Britain - Pension - NEST summary: Connect to an existing NEST employer description: >- Connects the organisation to an employer already registered with NEST, by its employer reference. Nothing is created in NEST: the employer's groups and payment sources are read and recorded. The employer must have granted Intermezzo delegate access in NEST. Returns 202 with a submission ID; poll /nest/status for the outcome. operationId: nest_link_gb_organizations__organization_id__pension_nest_link_post parameters: - name: organization_id in: path required: true schema: type: string title: Organization Id requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/NestLinkEmployerRequest' responses: '202': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/NestOperationAccepted' '409': description: >- - `NEST_EMPLOYER_REFERENCE_MISMATCH`: Raised when link names a NEST employer other than the one the organisation is connected to. - `NEST_EMPLOYER_REFERENCE_TAKEN`: Raised when a NEST employer is already connected to another organisation. - `NEST_SETUP_IN_PROGRESS`: Raised when a NEST operation is requested while another is in flight for the organisation. content: application/json: examples: NEST_EMPLOYER_REFERENCE_MISMATCH: summary: >- Raised when link names a NEST employer other than the one the organisation is connected to. value: errors: - code: NEST_EMPLOYER_REFERENCE_MISMATCH message: >- Raised when link names a NEST employer other than the one the organisation is connected to. NEST_EMPLOYER_REFERENCE_TAKEN: summary: >- Raised when a NEST employer is already connected to another organisation. value: errors: - code: NEST_EMPLOYER_REFERENCE_TAKEN message: >- Raised when a NEST employer is already connected to another organisation. NEST_SETUP_IN_PROGRESS: summary: >- Raised when a NEST operation is requested while another is in flight for the organisation. value: errors: - code: NEST_SETUP_IN_PROGRESS message: >- Raised when a NEST operation is requested while another is in flight for the organisation. schema: $ref: '#/components/schemas/ErrorResponse' '422': description: >- The request failed validation. Type and format errors use the generic FIELD_* codes. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: >- - `NEST_NOT_CONFIGURED`: Raised when NEST delegate credentials are missing from settings. content: application/json: examples: NEST_NOT_CONFIGURED: summary: >- Raised when NEST delegate credentials are missing from settings. value: errors: - code: NEST_NOT_CONFIGURED message: >- Raised when NEST delegate credentials are missing from settings. schema: $ref: '#/components/schemas/ErrorResponse' security: - BearerToken: [] components: schemas: NestLinkEmployerRequest: properties: employer_reference_number: type: string pattern: ^EMP\d{9}$ title: Employer Reference Number description: >- The employer's existing NEST reference number (EMP followed by 9 digits) type: object required: - employer_reference_number title: NestLinkEmployerRequest NestOperationAccepted: properties: submission_id: type: string title: Submission Id status: type: string const: PENDING title: Status default: PENDING type: object required: - submission_id title: NestOperationAccepted ErrorResponse: properties: errors: items: $ref: '#/components/schemas/ErrorDetail' type: array title: Errors description: Errors that occurred additionalProperties: false type: object required: - errors title: ErrorResponse description: >- Body of every error response: PayrollExceptions and request validation errors. ErrorDetail: properties: code: anyOf: - $ref: '#/components/schemas/ErrorCode' - $ref: '#/components/schemas/PydanticErrorCode' title: Code description: Unique error code for i18n lookup message: type: string title: Message description: English fallback error message field: anyOf: - type: string - type: 'null' title: Field description: Field that caused the error params: anyOf: - additionalProperties: true type: object - type: 'null' title: Params description: Parameters for translation interpolation additionalProperties: false type: object required: - code - message title: ErrorDetail description: |- Represents an error that occurred during processing. Designed for client-side i18n: - code: Use this to look up translation (e.g., "ORG_NOT_FOUND") - message: English fallback if translation not available - field: Field name for form validation highlighting - params: Dynamic values for translation interpolation ErrorCode: type: string enum: - ADDRESS_NOT_FOUND - ADDRESS_CREATION_ERROR - ADDRESS_UPDATING_ERROR - ADDRESS_COUNTRY_CODE_MISMATCH - ORG_NOT_FOUND - ORG_DUPLICATE_EXTERNAL_REF - ORG_HAS_ACTIVE_EMPLOYEES - ORG_ALREADY_SHUTDOWN - ORG_COUNTRY_CHANGE_NOT_ALLOWED - ORG_BELONGS_TO_A_DIFFERENT_COUNTRY - COUNTRY_NOT_SUPPORTED - CONTACT_NOT_FOUND - CONTACT_ACCESS_DENIED - WORKSITE_NOT_FOUND - BANK_ACCOUNT_NOT_FOUND - BANK_ACCOUNT_MISSING_SWIFT - BANK_ACCOUNT_MISSING_IBAN - BANK_ACCOUNT_INVALID_COMBINATION - BANK_ACCOUNT_NOT_ASSOCIATED_WITH_ORG - EMPLOYEE_NOT_FOUND - EMPLOYEE_ACCESS_DENIED - EMPLOYEES_ACCESS_DENIED - EMPLOYEES_DO_NOT_BELONG_TO_PAY_GROUP - EMPLOYEES_ASSIGNED_TO_PAY_GROUP - EMPLOYEE_IN_OPEN_PAYROLL - DUPLICATE_EMPLOYEE_IDS - PAYROLL_STATUS_NOT_FOUND - TASK_STATUS_CHECKER_NOT_FOUND - PAYROLL_TASK_INVALID_STATUS - CALCULATION_TASK_NOT_FOUND_IN_PAYROLL - PAYRUN_ALREADY_EXISTS - PAYRUN_NOT_FOUND - PAYRUN_NOT_IN_DRAFT_STATUS - PAYRUN_NOT_APPROVED - PAYRUN_STILL_PROCESSING - PAYRUN_MISSING_PAYSLIPS - PAYRUN_OPERATION_FAILED - PAYRUN_CONTAINS_EMPLOYEES_NOT_IN_PAY_GROUP - PAYRUN_EMPTY_PAY_DETAILS - PAYRUN_NMW_VIOLATIONS - SACRIFICE_NOT_ALLOWED - PAY_GROUP_NOT_FOUND - ONE_OR_MORE_PAY_GROUP_NOT_FOUND - PAY_GROUP_IS_IN_RUNNING_PAYROLL - PAY_CALENDAR_NOT_FOUND - PAY_PERIOD_UNRESOLVED - GB_PRORATION_BASIS_MALFORMED - INSURANCE_DATA_NOT_FOUND - INSURANCE_OPERATION_FAILED - PREFERENCES_NOT_FOUND - TAX_IDENTIFIER_NOT_FOUND - TAX_DATA_REQUIRED - PAYSLIP_OPERATION_FAILED - PAYSLIP_PDF_GENERATION_FAILED - PAYSLIP_FPS_VALIDATION_FAILED - PAYSLIP_FPS_SUBMISSION_FAILED - PAYSLIP_FPS_POLLING_FAILED - PAYSLIP_NOT_FOUND - DOCUMENT_NOT_FOUND - DOCUMENT_ACCESS_DENIED - DOCUMENT_UPLOAD_FAILED - DOCUMENT_DOWNLOAD_FAILED - DOCUMENT_DELETION_FAILED - DOCUMENT_OPERATION_FAILED - DOCUMENT_INVALID_TYPE - DOCUMENT_SIZE_EXCEEDED - DOCUMENT_UNSUPPORTED_FILE_TYPE - DOCUMENT_RATE_LIMIT_EXCEEDED - DOCUMENT_TEMPLATE_NOT_FOUND - DOCUMENT_TEMPLATE_INVALID_SYNTAX - DOCUMENT_TEMPLATE_ALREADY_ACTIVE - DOCUMENT_TEMPLATE_OPERATION_FAILED - WAGE_TYPE_NOT_FOUND - WAGE_TYPE_ALREADY_EXISTS - WAGE_TYPE_DRAFT_EXISTS - WAGE_TYPE_INVALID_DATE - COMPENSATION_EFFECTIVE_DATE_TOO_OLD - COMPENSATION_PAY_GROUP_READ_ONLY - PENSION_SCHEME_NOT_FOUND - PENSION_SCHEME_ALREADY_EXISTS - PENSION_SCHEME_INVALID_VALID_FROM - PENSION_MEMBERSHIP_NOT_FOUND - PENSION_MEMBERSHIP_ALREADY_ACTIVE - PENSION_MEMBERSHIP_NOT_ACTIVE - PENSION_MEMBERSHIP_INVALID_VALID_FROM - PENSION_WAGE_TYPE_OVERRIDE_INCOMPLETE - PENSION_WAGE_TYPE_MISMATCH - PENSION_RATE_BELOW_MINIMUM - PENSION_INVALID_ENTRY_ROUTE - PENSION_OPT_IN_TOO_SOON - PENSION_JOIN_NOT_ENTITLED - PENSION_NO_FUTURE_PAY_PERIOD - PENSION_FIXED_AMOUNT_RATE_EXCLUSIVE - PENSION_INVALID_STATE_TRANSITION - NEST_ALREADY_CONNECTED - NEST_EMPLOYER_REFERENCE_MISMATCH - NEST_EMPLOYER_REFERENCE_TAKEN - NEST_NOT_CONNECTED - NEST_SETUP_IN_PROGRESS - NEST_SCHEME_NOT_NEST_PROVIDER - NEST_SCHEME_MISSING_CONFIG - NEST_SCHEME_NOT_API_SUBMISSION - NEST_NOT_CONFIGURED - NEST_PROVIDER_CONFIG_INVALID - NEST_PROVIDER_CONFIG_LOCKED - NEST_SETUP_MISSING_DATA - NEST_SETUP_UNSUPPORTED - NEST_FIRST_EPED_IN_PAST - P32_EA_INELIGIBLE - P32_RECORD_NOT_FOUND - P32_NO_SURPLUS - P32_REPAYMENT_EXCEEDS_SURPLUS - HMRC_STATUS_NOT_FOUND - HMRC_INVALID_STATE_TRANSITION - EPS_NOT_FOUND - FPS_SUBMISSION_NOT_FOUND - FPS_PAYMENT_AFTER_LEAVING_WITHOUT_LEAVING_DATE - EPS_DATE_SCHEME_CEASED_IN_FUTURE - EPS_FINAL_SUBMISSION_NO_TYPE - EPS_DATE_SCHEME_CEASED_WITHOUT_SCHEME_CEASED - EPS_RECOVERABLE_AMOUNTS_NO_FIELDS - EPS_NO_SECTIONS_PROVIDED - P11D_INVALID_TAX_YEAR - P11D_OUTSIDE_FILING_WINDOW - P11D_NOT_FOUND - P11D_DELETE_BLOCKED - BACS_SUN_NOT_CONFIGURED - BACS_FILE_NOT_FOUND - BACS_TASK_NOT_SCHEDULED - BACS_TASK_IN_PROGRESS - BACS_TASK_FAILED - BACS_NO_PAYMENTS - BACS_FILE_LATE - GB_RTI_ID_DUPLICATE - GB_RTI_ID_REUSED_IN_TAX_YEAR - GB_PAYROLL_CALCULATION_RESULTS_NOT_READY - GB_VALUED_GROUP_NOT_DECLARED - GB_PRORATION_INPUT_ERROR - GB_UNCLAIMED_SEGMENT - GB_SMP_TOP_UP_BASIS_MISSING - GB_PRIOR_SLICE_WITHOUT_CURRENT_LINE - GB_PRESENCE_FACTOR_NOT_SET - GB_CONFLICTING_PRESENCE_FACTOR - GB_PENSION_EARNINGS_DEFINITION_UNHANDLED - GB_EARNINGS_HISTORY_GAP - GB_EARNINGS_HISTORY_MIGRATION_INVALID - GB_EARNINGS_HISTORY_RANGE_INVALID - GB_AWE_PAY_DAY_COUNT_MISMATCH - GB_PERIOD_FIGURES_INCOMPLETE - GB_WAGE_TYPE_NIC_CLASS_CONFLICT - GB_GROSSUP_FLOW_ORDER - REPORT_NOT_FOUND - REPORT_ALREADY_EXISTS - REPORT_DOCUMENT_MISSING - GTN_NO_APPROVED_PAYSLIPS - YTD_NO_PAYSLIPS - REPORT_EMPLOYEE_DATA_MISSING - VARIANCE_REPORT_NOT_FOUND - ORG_SCOPED_REPORT_SCOPE_MISMATCH - EMPLOYEE_SCOPED_REPORT_SCOPE_MISMATCH - FPS_SUMMARY_NO_PAYRUNS - P45_NOT_GENERATED - P45_EMPLOYEE_NOT_LEAVER - P45_MISSING_EMPLOYER_TAX_IDENTIFIER - P60_NO_QUALIFYING_EMPLOYEES - P60_NOT_GENERATED - P60_MISSING_EMPLOYER_TAX_IDENTIFIER - P60_NI_CATEGORY_MISMATCH - EXB_SUBMISSION_ALREADY_EXISTS - EXB_SUBMISSION_NOT_FOUND - EXB_OUTSIDE_FILING_WINDOW - EXB_INVALID_TAX_YEAR - P46_CAR_NOT_FOUND - P46_CAR_LOCKED - PENSION_REPORT_NOT_FOUND - PAYROLL_LIABILITY_REPORT_NO_DATA - PAYROLL_LIABILITY_PAY_DATE_TAX_PERIOD_UNRESOLVED - ABSENCE_NOT_FOUND - ABSENCE_CANCELLED - GB_ABSENCE_OVERLAP - GB_ABSENCE_COMPULSORY_LEAVE - GB_ABSENCE_DUPLICATE_KIT_DAY - GB_ABSENCE_EMPLOYEE_COUNTRY_MISMATCH - GB_ABSENCE_FACTS_OMITTED - GB_ABSENCE_CONTENT_MALFORMED - GB_ABSENCE_WRITE_WITHOUT_LOCK - GB_ABSENCE_SCHEME_NOT_FOUND - GB_ABSENCE_SCHEME_REGIME_IMMUTABLE - GB_ABSENCE_SCHEME_TERMS_MALFORMED - GB_ABSENCE_SCHEME_TOP_UP_WAGE_TYPE_INVALID - GB_ABSENCE_SCHEME_EDITION_BACKDATED - GB_ABSENCE_SCHEME_IN_USE - GB_ABSENCE_SCHEME_ASSIGNMENT_NOT_FOUND - GB_ABSENCE_SCHEME_ASSIGNMENT_UNKNOWN_SCHEME - GB_ABSENCE_SCHEME_ASSIGNMENT_REGIME_MISMATCH - GB_ABSENCE_SCHEME_ASSIGNMENT_BACKDATED - GB_ABSENCE_SCHEME_ASSIGNMENT_INVALID_END - GB_ABSENCE_SCHEME_ASSIGNMENT_TARGET_INVALID - GB_ABSENCE_SCHEME_NO_TERMS_IN_FORCE - GB_ABSENCE_SCHEME_REGIME_MISMATCH - GB_SMP_PRESCRIBED_RATE_UNKNOWN - GB_SMP_START_TOO_EARLY - GB_SMP_EVIDENCE_MISSING - GB_SMP_CLAIM_ANCHOR_MISMATCH - GB_SMP_STATUTORY_WAGE_TYPE_MISSING - GB_SMP_ALLOCATION_PREFERENCE_MALFORMED - GB_SMP_PAY_CALENDAR_INCONSISTENT - GB_SMP_CURSOR_MALFORMED - GB_SMP_TOP_UP_WAGE_TYPE_MISSING - GB_SMP_ALLOCATION_MODE_CHANGED - GB_SMP_DEFERRED_TOP_UP_STAMPED - GB_SMP_PERIOD_GRID_AMBIGUOUS - GB_SMP_LINE_META_VERSION_UNKNOWN - DEFINITION_EDITION_MISSING - DEFINITION_EDITION_GAP - HUB_NOT_FOUND - HUB_CLOSED - HUB_DUPLICATE_EXTERNAL_REF - EDITION_MISMATCH - PRECONDITION_REQUIRED - PRECONDITION_MALFORMED - RANGE_CROSSES_EDITION - VALUE_OUT_OF_RANGE - SATELLITE_INCOMPLETE title: ErrorCode description: |- Centralized error codes for i18n translation. Naming convention: {RESOURCE}_{ERROR_TYPE} - ORG_NOT_FOUND - Organization not found PydanticErrorCode: type: string enum: - FIELD_REQUIRED - FIELD_INVALID_TYPE_STRING - FIELD_INVALID_TYPE_INT - FIELD_INVALID_TYPE_FLOAT - FIELD_INVALID_TYPE_BOOL - FIELD_INVALID_TYPE_DICT - FIELD_INVALID_TYPE_LIST - FIELD_STRING_TOO_SHORT - FIELD_STRING_TOO_LONG - FIELD_STRING_PATTERN_MISMATCH - FIELD_VALUE_TOO_SMALL - FIELD_VALUE_TOO_LARGE - FIELD_INVALID_DATE - FIELD_INVALID_DATETIME - FIELD_INVALID_TIME - FIELD_INVALID_DATE_FORMAT - FIELD_INVALID_DATETIME_FORMAT - FIELD_INVALID_ENUM_VALUE - FIELD_INVALID_EMAIL - FIELD_INVALID_URL - FIELD_LIST_TOO_SHORT - FIELD_LIST_TOO_LONG - FIELD_UNKNOWN - FIELD_VALIDATION_ERROR title: PydanticErrorCode description: |- Error codes for Pydantic validation errors. Maps Pydantic error types to our error codes for i18n. securitySchemes: BearerToken: type: http scheme: bearer bearerFormat: JWT description: Get token from Auth0 and paste it here ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.