> ## Documentation Index > Fetch the complete documentation index at: https://api.nektir.com/llms.txt > Use this file to discover all available pages before exploring further. # Resume observed changes from a durable publication checkpoint > With neither token, returns no events and a checkpoint covering the current publication. Capture that checkpoint BEFORE requesting a baseline export, then poll with `checkpoint`. Events are ordered oldest-first by publication and event within (completed checkpoint, frozen publication]. Retrieval time is not used as a synchronization watermark. If has_more is true, follow next_cursor alone with the same filters. Only the final page returns a new checkpoint; commit it atomically with processing that page. Retried pages may repeat event UUIDs. Empty filtered windows still advance the checkpoint. Checkpoints are signed, filter-bound and independent of page-cursor and version-history TTLs. History deletion/reset can return 410 CHECKPOINT_EXPIRED: import a new baseline. 410 CURSOR_EXPIRED instead means retry from the last completed checkpoint and deduplicate. This is observed-product-change invalidation, not every successful retrieval or store-directory CDC. No source requests are triggered. Family and observed-time filters are not supported here. ## OpenAPI ````yaml /openapi/v1.yaml get /changes/sync openapi: 3.1.0 info: title: Independent Utah DABS API version: 1.0.0 summary: Database-backed product, store, and reported-inventory reads description: > Version 1 pilot contract. All requests read a locally published database revision; no public request waits for or triggers Utah DABS. Reported quantities are observations, not purchase guarantees. This service is independent and is not affiliated with or endorsed by Utah DABS. The current local seed contains historical inventory fixtures; clients must inspect response warnings and coverage metadata. Every GET resource also supports HEAD with the same parameters, status codes, cache validators, and representation headers, but no response body. Conditional HEAD supports 304, and HEAD product details do not record product views. servers: - url: http://127.0.0.1:5185/v1 description: Local development only; set MINTLIFY_API_BASE_URL before publishing security: [] tags: - name: Products - name: Search - name: Brands - name: Product families - name: Changes - name: Exports - name: Stores - name: Availability - name: Metadata paths: /changes/sync: get: tags: - Changes summary: Resume observed changes from a durable publication checkpoint description: > With neither token, returns no events and a checkpoint covering the current publication. Capture that checkpoint BEFORE requesting a baseline export, then poll with `checkpoint`. Events are ordered oldest-first by publication and event within (completed checkpoint, frozen publication]. Retrieval time is not used as a synchronization watermark. If has_more is true, follow next_cursor alone with the same filters. Only the final page returns a new checkpoint; commit it atomically with processing that page. Retried pages may repeat event UUIDs. Empty filtered windows still advance the checkpoint. Checkpoints are signed, filter-bound and independent of page-cursor and version-history TTLs. History deletion/reset can return 410 CHECKPOINT_EXPIRED: import a new baseline. 410 CURSOR_EXPIRED instead means retry from the last completed checkpoint and deduplicate. This is observed-product-change invalidation, not every successful retrieval or store-directory CDC. No source requests are triggered. Family and observed-time filters are not supported here. operationId: synchronizeProductChanges parameters: - $ref: '#/components/parameters/ChangeProductId' - $ref: '#/components/parameters/ChangeSku' - $ref: '#/components/parameters/ChangeStoreId' - $ref: '#/components/parameters/ChangeTypes' - name: checkpoint in: query description: >- Opaque completed-window token. Mutually exclusive with cursor. Omit both only when starting a new baseline. schema: type: string minLength: 1 maxLength: 4096 - $ref: '#/components/parameters/Cursor' - $ref: '#/components/parameters/Limit' - $ref: '#/components/parameters/IfNoneMatch' - $ref: '#/components/parameters/IfModifiedSince' responses: '200': description: >- Frozen ascending event page, or initial checkpoint. New completed checkpoint is null until the last page. headers: X-Publication-Revision: $ref: '#/components/headers/PublicationRevision' Cache-Control: schema: type: string const: no-store content: application/json: schema: $ref: '#/components/schemas/ProductChangeSyncResponse' '304': $ref: '#/components/responses/NotModified' '400': $ref: '#/components/responses/BadRequest' '410': description: >- CHECKPOINT_EXPIRED requires a new baseline; CURSOR_EXPIRED permits replay from the last completed checkpoint. No silent gaps. content: application/problem+json: schema: $ref: '#/components/schemas/Problem' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/InternalError' '503': $ref: '#/components/responses/Unavailable' components: parameters: ChangeProductId: name: product_id in: query description: Stable API-owned product UUID. Mutually exclusive with `sku`. schema: type: string format: uuid ChangeSku: name: sku in: query description: Exact six-character Utah DABS SKU. Mutually exclusive with `product_id`. schema: $ref: '#/components/schemas/DabsSku' ChangeStoreId: name: store_id in: query description: >- Restrict store-level inventory events to one stable API-owned store UUID. schema: type: string format: uuid ChangeTypes: name: types in: query style: form explode: false description: Comma-separated observed event types with OR semantics. schema: type: array maxItems: 8 uniqueItems: true items: $ref: '#/components/schemas/ProductChangeType' Cursor: name: cursor in: query description: >- Signed opaque keyset cursor, valid for 15 minutes and only with the original resource endpoint, query, and sort. Reuse on another endpoint or with changed filters returns CURSOR_QUERY_MISMATCH. Follow links.next unchanged. schema: type: string maxLength: 2048 Limit: name: limit in: query schema: type: integer minimum: 1 maximum: 100 default: 25 IfNoneMatch: name: If-None-Match in: header description: Strong entity tag from an earlier response. schema: type: string IfModifiedSince: name: If-Modified-Since in: header description: HTTP-date fallback validator. ETag takes precedence. schema: type: string headers: PublicationRevision: description: Immutable API publication revision used for this representation. schema: type: string format: uuid ETag: description: >- Strong validator for the response representation. A new publication may retain the validator when this response is unchanged. schema: type: string example: '"v1-018f2fd0-a3d4-7d20-9c11-9482722f6b26-a91c"' RetryAfter: description: Seconds until retry or an HTTP-date. schema: type: string RequestId: description: >- Server-generated identifier for correlating a response with private operational logs. schema: type: string format: uuid schemas: ProductChangeSyncResponse: type: object additionalProperties: false required: - data - meta - links properties: data: type: array maxItems: 100 items: $ref: '#/components/schemas/ProductChange' meta: type: object additionalProperties: false required: - page - sync - warnings properties: page: $ref: '#/components/schemas/PageMeta' sync: type: object additionalProperties: false required: - checkpoint - scope - order properties: checkpoint: type: - string - 'null' description: >- Save only after completing the window. Null on intermediate pages. scope: type: string const: observed_product_changes order: type: string const: publication_then_event warnings: type: array items: $ref: '#/components/schemas/Warning' links: $ref: '#/components/schemas/Links' Problem: type: object additionalProperties: false required: - type - title - status - detail - instance - code - request_id properties: type: type: string format: uri title: type: string status: type: integer minimum: 400 maximum: 599 detail: type: string instance: type: string format: uri-reference code: type: string request_id: type: string format: uuid invalid_params: type: array items: $ref: '#/components/schemas/InvalidParameter' DabsSku: type: string pattern: ^[0-9]{6}$ examples: - '347210' - '004190' ProductChangeType: type: string enum: - product_first_observed - price_changed - status_changed - product_presentation_changed - aggregate_inventory_changed - store_inventory_first_observed - store_inventory_changed - catalog_presence_changed ProductChange: type: object additionalProperties: false required: - id - type - product - store - change - semantics - times - upstream_age_known properties: id: type: string format: uuid type: $ref: '#/components/schemas/ProductChangeType' product: $ref: '#/components/schemas/ProductChangeProduct' store: oneOf: - $ref: '#/components/schemas/ProductChangeStore' - type: 'null' change: type: object description: >- Type-specific immutable previous/current values. Explicit JSON nulls are meaningful unknown values. additionalProperties: true semantics: type: string enum: - first_observed_by_nektir - published_value_change - published_presentation_change - reported_observation_change_not_inferred_sale - baseline_observation_not_restock - source_presence_change_missing_does_not_imply_zero_inventory times: $ref: '#/components/schemas/NullableObservationTimes' upstream_age_known: type: boolean PageMeta: type: object additionalProperties: false required: - has_more - next_cursor properties: has_more: type: boolean next_cursor: type: - string - 'null' cursor_expires_at: type: string format: date-time description: Present only when `next_cursor` is non-null. Warning: type: object additionalProperties: false description: >- Machine-readable data qualification. Current codes include FIXTURE_DATA, INVENTORY_COVERAGE_PARTIAL, SOURCE_REFRESH_DELAYED, UPSTREAM_PRODUCT_UNAVAILABLE, SOURCE_SCHEMA_QUARANTINED, and CATALOG_BATCH_OLD. required: - code properties: code: type: string examples: - INVENTORY_COVERAGE_PARTIAL Links: type: object additionalProperties: false required: - self - next properties: self: type: string format: uri-reference next: type: - string - 'null' format: uri-reference InvalidParameter: type: object additionalProperties: false required: - name - reason properties: name: type: string reason: type: string ProductChangeProduct: type: object additionalProperties: false required: - id - source_ids - name - brand properties: id: type: string format: uuid source_ids: $ref: '#/components/schemas/SourceProductIds' name: type: string description: >- Consumer display title without the resolved brand or a trailing package dimension when one was captured in the event label. brand: type: - string - 'null' ProductChangeStore: type: object additionalProperties: false required: - id - source_ids - name properties: id: type: string format: uuid source_ids: type: object additionalProperties: false required: - inventory_store_code properties: inventory_store_code: $ref: '#/components/schemas/StoreInventoryCode' name: type: string NullableObservationTimes: type: object additionalProperties: false required: - source_updated_at - retrieved_at - published_at properties: source_updated_at: type: - string - 'null' format: date-time retrieved_at: type: - string - 'null' format: date-time published_at: type: - string - 'null' format: date-time SourceProductIds: type: object additionalProperties: false required: - utah_dabs_sku properties: utah_dabs_sku: $ref: '#/components/schemas/DabsSku' StoreInventoryCode: type: string pattern: ^[0-9]{4}$ examples: - '0002' responses: NotModified: description: Representation has not changed for the supplied validator. headers: ETag: $ref: '#/components/headers/ETag' Cache-Control: description: Cache policy for the validated representation. schema: type: string X-Publication-Revision: $ref: '#/components/headers/PublicationRevision' BadRequest: description: Invalid parameters, incompatible scope, or cursor/query mismatch. headers: Cache-Control: schema: type: string example: no-store content: application/problem+json: schema: $ref: '#/components/schemas/Problem' RateLimited: description: Public read-rate limit exceeded. headers: Cache-Control: schema: type: string example: no-store Retry-After: $ref: '#/components/headers/RetryAfter' content: application/problem+json: schema: $ref: '#/components/schemas/Problem' InternalError: description: >- An unexpected server failure. Details are withheld; report the response request identifier. headers: Cache-Control: schema: type: string example: no-store X-Request-ID: $ref: '#/components/headers/RequestId' content: application/problem+json: schema: $ref: '#/components/schemas/Problem' Unavailable: description: >- The serving database is unavailable, or an export is busy or exceeds a configured build limit. Keep last-known-good data and honor Retry-After. Persistent EXPORT_UNAVAILABLE size or deadline failures need operator review. headers: Cache-Control: schema: type: string example: no-store Retry-After: $ref: '#/components/headers/RetryAfter' content: application/problem+json: schema: $ref: '#/components/schemas/Problem' ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.