> ## Documentation Index > Fetch the complete documentation index at: https://www.finseed.es/docs/llms.txt > Use this file to discover all available pages before exploring further. # Delete a number series > Deletes a number series that no invoice or integration references. A series that has issued invoices, or that an integration is configured to use, cannot be deleted and the request fails with `number_series_in_use`. ## OpenAPI ````yaml /api-reference/openapi.json delete /v1/number_series/{id} openapi: 3.1.0 info: title: Finseed API version: 1.0.0 description: >- REST API for programmatic Verifactu invoicing. Every request is sent over HTTPS and authenticated with an API key passed as a bearer token. Each key is scoped to a single environment (test or live). Payloads are JSON with snake_case fields: amounts are integer minor units (cents) and timestamps are RFC 3339 in UTC. List endpoints are cursor-paginated. Errors return a small application/json envelope with a stable, machine-readable `code`. servers: - url: https://api.finseed.es security: - bearerAuth: [] paths: /v1/number_series/{id}: delete: tags: - Number Series summary: Delete a number series description: >- Deletes a number series that no invoice or integration references. A series that has issued invoices, or that an integration is configured to use, cannot be deleted and the request fails with `number_series_in_use`. operationId: deleteNumberSeries parameters: - name: id in: path required: true description: Opaque number series identifier — the `id` from a list row. schema: type: string responses: '200': description: Confirmation that the number series was deleted. content: application/json: schema: $ref: '#/components/schemas/NumberSeriesDeleted' '401': description: >- Authentication failed: the API key is missing, malformed, or revoked. Send a valid key as a bearer token in the `Authorization` header. Each key is bound to a single environment (test or live). content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: code: unauthorized detail: >- Authentication failed. Send your API key as a bearer token in the `Authorization` header. Keys are scoped to one environment, so a test key cannot read live data and vice versa. errors: [] doc_url: https://www.finseed.es/docs/api-reference/errors#unauthorized '404': description: >- No number series matches the supplied identifier in the environment the API key belongs to. A number series created with a live key is not visible to a test key, and vice versa. content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: code: number_series_not_found detail: >- No number series matches that identifier in this environment. Note that test and live keys see different number series. errors: [] doc_url: >- https://www.finseed.es/docs/api-reference/errors#number_series_not_found '409': description: >- The number series cannot be deleted because invoices have been issued on it or an integration is configured to use it. A series is immutable once created (there is no update endpoint), so the way to change numbering is to create a new series and issue future invoices on it. A series referenced by an integration can be deleted after the integration is pointed elsewhere. content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: code: number_series_in_use detail: >- This number series cannot be deleted because invoices or integrations reference it. A series is immutable once created: to change how invoices are numbered, create a new series and issue on that one instead. errors: [] doc_url: >- https://www.finseed.es/docs/api-reference/errors#number_series_in_use '500': description: >- An unexpected error occurred on our side. No partial work is persisted, so the request can be retried safely. content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' example: code: internal_error detail: >- Something went wrong on our side. The request did not complete and can be retried safely. errors: [] doc_url: >- https://www.finseed.es/docs/api-reference/errors#internal_error components: schemas: NumberSeriesDeleted: type: object properties: id: type: string description: The identifier of the deleted number series. example: ns_clx123abc456 deleted: type: boolean const: true description: 'Always true: confirms the series no longer exists.' example: true required: - id - deleted additionalProperties: false description: Confirmation that a number series was deleted. example: id: ns_clx123abc456 deleted: true ErrorEnvelope: type: object properties: code: type: string description: >- Stable, machine-readable error code. The branch key. This is an extensible enum: new values may be added in the future, so clients must tolerate values not listed here. Known values: invalid_request, unauthorized, invoice_not_found, download_link_expired, number_series_not_found, number_series_prefix_taken, number_series_in_use, customer_not_found, customer_ambiguous, idempotency_conflict, rate_limited, invalid_number_series, invalid_tax_rate, invalid_tax_data, invalid_tax_id, tax_id_type_country_mismatch, insufficient_recipient_data, simplified_amount_exceeded, simplified_incompatible_tax_type, invalid_recargo_equivalencia, aeat_mandate_not_approved, no_active_subscription, tax_id_validation_unavailable, invalid_rectifies_reference, rectified_invoice_not_found, invoice_already_voided, invoice_already_replaced, invoice_not_family_tip, invoice_pending_at_aeat, invoice_not_rectifiable_at_aeat, family_balance_below_zero, replacement_total_negative, reason_incompatible_with_recipient, recipient_overrides_not_allowed_for_differences, rectifying_series_invalid, external_reference_invalid, external_reference_matches_existing_invoice, rectified_amounts_required_for_substitution, line_item_without_tax_items, internal_error. example: invalid_request detail: type: string description: Human-readable, context-specific explanation. example: The query parameters are not valid. errors: type: array items: type: object properties: field: type: string description: Location of the offending value (JSON path). example: limit code: type: string description: Machine-readable validation issue code. example: too_big message: type: string description: Human-readable explanation of the field-level issue. example: Number must be less than or equal to 100 required: - field - code - message additionalProperties: false description: >- Field-level issues. Always present; empty unless this is a validation failure. doc_url: type: string description: Link to the reference documentation for this error code. example: https://www.finseed.es/docs/api-reference/errors#invalid_request required: - code - detail - errors - doc_url additionalProperties: false description: >- Uniform error body returned for every non-2xx response (application/json). securitySchemes: bearerAuth: type: http scheme: bearer description: API key sent as a bearer token in the `Authorization` header. ````