> ## Documentation Index > Fetch the complete documentation index at: https://docs.platform.toloka.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Mark a deterministic sample of rows > Send `markField`, `markValue`, and exactly one of `count` or `fraction`, with an optional filter. Marks a repeatable subset of rows in the background and returns a sampling ID. Increasing the size extends the existing sample. ## OpenAPI ````yaml /api-reference/openapi.json post /datasets/{datasetId}/sample openapi: 3.1.0 info: description: >- Manage projects, datasets, labeling pipelines, and model training. **Beta:** endpoints, request and response shapes, and error contracts can change without notice or a backward-compatibility promise. title: Toloka Platform API version: 2.0.0 servers: - url: https://platform.toloka.ai/api/v2-beta security: - apiKeyAuth: [] - scopedTokenAuth: [] tags: - description: The authenticated API key owner. name: Account - description: A project is the container for pipelines, datasets, and files. name: Projects - description: Rows and typed fields. Field schemas are immutable once created. name: Datasets - description: Append rows to a dataset from a file. name: Dataset uploads - description: Read a dataset out as a file. name: Dataset exports - description: A pipeline is a graph of nodes that processes each dataset item. name: Pipelines - description: The nodes, connections, fields, and version of a pipeline graph. name: Pipeline graph - description: Execute a pipeline over a dataset and inspect each item. name: Runs - description: Per-node checks that a pipeline must pass before deployment. name: Checks - description: Named credentials available to pipeline code. name: Secrets - description: Project files available to pipeline code and labeling interfaces. name: Files - description: >- Global, read-only catalog of the models a synthetic generation node can use, with their budget bounds. name: Generation models - description: >- Global, read-only catalog of the expert audience: the values a node `audience` filter can use. name: Audience - description: >- Project lists of experts a node can take its workforce from with `audienceMode: service`. Available only to teams with the audience service enabled. name: Expert lists - description: >- Experts banned in a project: they cannot be invited and are removed from the work they are in. Available only to teams with expert bans enabled. name: Expert ban list - description: Global, read-only base model catalog. name: Base models - description: Project-owned mutable model-training drafts. name: Trainings - description: Project-owned Models and immutable Model Versions. name: Models - name: Batch inference paths: /datasets/{datasetId}/sample: post: tags: - Datasets summary: Mark a deterministic sample of rows description: >- Send `markField`, `markValue`, and exactly one of `count` or `fraction`, with an optional filter. Marks a repeatable subset of rows in the background and returns a sampling ID. Increasing the size extends the existing sample. operationId: sampleDatasetItems parameters: - in: path name: datasetId required: true schema: $ref: '#/components/schemas/DatasetId' requestBody: content: application/json: schema: anyOf: - additionalProperties: false properties: count: description: >- How many rows to end up marked with this value, capped at how many the filter matches. exclusiveMinimum: 0 maximum: 9007199254740991 type: integer itemFilter: $ref: '#/components/schemas/DatasetItemFilter' markField: description: Field the marker is written to, by field name or id. type: string markValue: description: >- Value written into the marker field, for example "golden". maxLength: 64 minLength: 1 type: string required: - markField - markValue - count type: object - additionalProperties: false properties: fraction: description: Share of the matching rows to end up marked, rounded up. exclusiveMinimum: 0 maximum: 1 type: number itemFilter: $ref: '#/components/schemas/DatasetItemFilter' markField: description: Field the marker is written to, by field name or id. type: string markValue: description: >- Value written into the marker field, for example "golden". maxLength: 64 minLength: 1 type: string required: - markField - markValue - fraction type: object description: >- Select exactly one of `count` or `fraction`, plus a marker field and value. Repeating the request preserves the sample; increasing its size extends it. responses: '200': content: application/json: schema: $ref: '#/components/schemas/SampleResult' description: Sampling started headers: RateLimit-Limit: $ref: '#/components/headers/RateLimit-Limit' RateLimit-Policy: $ref: '#/components/headers/RateLimit-Policy' RateLimit-Remaining: $ref: '#/components/headers/RateLimit-Remaining' RateLimit-Reset: $ref: '#/components/headers/RateLimit-Reset' X-Request-Id: $ref: '#/components/headers/X-Request-Id' '400': description: Unknown field or invalid count, fraction, or marker headers: RateLimit-Limit: $ref: '#/components/headers/RateLimit-Limit' RateLimit-Policy: $ref: '#/components/headers/RateLimit-Policy' RateLimit-Remaining: $ref: '#/components/headers/RateLimit-Remaining' RateLimit-Reset: $ref: '#/components/headers/RateLimit-Reset' X-Request-Id: $ref: '#/components/headers/X-Request-Id' '404': description: Dataset not found headers: RateLimit-Limit: $ref: '#/components/headers/RateLimit-Limit' RateLimit-Policy: $ref: '#/components/headers/RateLimit-Policy' RateLimit-Remaining: $ref: '#/components/headers/RateLimit-Remaining' RateLimit-Reset: $ref: '#/components/headers/RateLimit-Reset' X-Request-Id: $ref: '#/components/headers/X-Request-Id' '429': description: Rate limit exceeded headers: RateLimit-Limit: $ref: '#/components/headers/RateLimit-Limit' RateLimit-Policy: $ref: '#/components/headers/RateLimit-Policy' RateLimit-Remaining: $ref: '#/components/headers/RateLimit-Remaining' RateLimit-Reset: $ref: '#/components/headers/RateLimit-Reset' X-Request-Id: $ref: '#/components/headers/X-Request-Id' components: schemas: DatasetId: description: Dataset ID with prefix `ds.`. pattern: >- ^ds\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string DatasetItemFilter: additionalProperties: false description: Narrow which rows are eligible. Omit to consider every row. properties: createdBefore: description: >- Cutoff for dataset items and field revisions, as an ISO 8601 timestamp; omit to use the endpoint's cutoff. format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d:[0-5]\d(?:\.\d+)?(?:Z))$ type: string excludeParts: $ref: '#/components/schemas/DatasetSplitPartExclusions' fieldSources: $ref: '#/components/schemas/DatasetFieldSourceConditions' fieldValues: $ref: '#/components/schemas/DatasetFieldValueConditions' missingRevisionFields: description: >- Field IDs with prefix `df.` that must have no revision on a selected row; defaults to an empty array. items: pattern: >- ^df\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string type: array parts: $ref: '#/components/schemas/DatasetSplitPartInclusion' slice: $ref: '#/components/schemas/DatasetSliceSelection' type: object SampleResult: properties: id: description: The sampling ID. Use it to poll the sampling status. pattern: >- ^dsm\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string target: description: >- The target number of marked rows, calculated when the request is made. Poll the sampling status for progress. maximum: 9007199254740991 minimum: 0 type: integer required: - id - target type: object DatasetSplitPartExclusions: description: Split-part selections to exclude; omit when no parts should be excluded. items: additionalProperties: false description: Split field and selected part names. properties: fieldId: description: Split field ID with prefix `df.`. pattern: >- ^df\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string names: description: Names of the split parts to select. items: maxLength: 64 pattern: ^[A-Za-z0-9_]+(?:[.-][A-Za-z0-9_]+)*$ type: string maxItems: 10 minItems: 1 type: array required: - fieldId - names type: object maxItems: 500 type: array DatasetFieldSourceConditions: description: >- Field-author conditions that selected rows must satisfy; defaults to no conditions. items: additionalProperties: false description: Required authors for a field. properties: fieldId: description: Dataset field ID with prefix `df.`. pattern: >- ^df\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string sources: description: Revision authors to match for this field. items: $ref: '#/components/schemas/FieldRevisionSource' minItems: 1 type: array required: - fieldId - sources type: object type: array DatasetFieldValueConditions: description: >- Field-value conditions that selected rows must satisfy; defaults to no conditions. items: additionalProperties: false description: Condition applied to a field value. properties: fieldId: description: Dataset field ID with prefix `df.` to compare. pattern: >- ^df\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string jsonPath: description: JSONPath locating the value within the field. minLength: 1 type: string latestOnly: default: true description: >- Whether to test only the latest revision from the allowed authors; false tests any revision, and the default is true. type: boolean operator: description: >- Text comparison: `text_eq` for equality or `text_neq` for inequality. enum: - text_eq - text_neq type: string sources: default: [] description: Allowed revision authors; an empty array allows any author. items: $ref: '#/components/schemas/FieldRevisionSource' type: array value: description: Scalar value compared as text; null is treated as an empty string. type: - string - number - boolean - 'null' required: - jsonPath - operator - value - fieldId type: object type: array DatasetSplitPartInclusion: additionalProperties: false description: Split parts to include; omit to include every part. properties: fieldId: description: Split field ID with prefix `df.`. pattern: >- ^df\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string names: description: Names of the split parts to select. items: maxLength: 64 pattern: ^[A-Za-z0-9_]+(?:[.-][A-Za-z0-9_]+)*$ type: string maxItems: 10 minItems: 1 type: array required: - fieldId - names type: object DatasetSliceSelection: additionalProperties: false description: >- Slice whose frozen rows and fields to read; omit to use live dataset rows. properties: sliceId: description: Dataset slice ID with prefix `dsl.`. pattern: >- ^dsl\.[0-9a-f]{8}-[0-9a-f]{4}-[7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ type: string required: - sliceId type: object FieldRevisionSource: description: Source that wrote a field revision. oneOf: - additionalProperties: false description: Source that wrote a field revision. properties: type: const: user description: >- Revision author: `user` for a user action or `system` for a platform operation. type: string userId: description: Identifier of the user who wrote the revision. minLength: 1 type: string required: - type - userId type: object - additionalProperties: false description: Source that wrote a field revision. properties: source: description: Identifier of the platform operation that wrote the revision. minLength: 1 type: string type: const: system description: >- Revision author: `user` for a user action or `system` for a platform operation. type: string required: - type - source type: object headers: RateLimit-Limit: description: The maximum number of requests allowed in the current window. schema: type: integer RateLimit-Policy: description: The rate limit policy (e.g., "60;w=60"). schema: type: string RateLimit-Remaining: description: The number of requests remaining in the current window. schema: type: integer RateLimit-Reset: description: The number of seconds until the current window resets. schema: type: integer X-Request-Id: description: >- The request id: the X-Request-Id you sent when it is 1-128 characters of letters, digits, ".", "_" or "-", otherwise a generated UUID. Present on every response, including errors; quote it when reporting a problem. schema: type: string securitySchemes: apiKeyAuth: description: >- Enter `ApiKey ` in Authorization, including the `ApiKey ` prefix. In cURL and Python samples, `` means this full value. The TypeScript SDK adds the prefix for you. in: header name: Authorization type: apiKey scopedTokenAuth: description: >- Enter the project-scoped token as `pst_...` in X-Scoped-Token, without an `ApiKey ` prefix. Create a token with POST /projects/{projectId}/tokens. in: header name: X-Scoped-Token type: apiKey ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.