> ## Documentation Index > Fetch the complete documentation index at: https://docs.mixpeek.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Feature Search > Search documents by vector similarity across collections. A convenience wrapper that builds an ad-hoc retriever with a single feature_search stage. ## OpenAPI ````yaml post /v1/features/search openapi: 3.1.0 info: title: Mixpeek API description: >- This is the Mixpeek API, providing access to various endpoints for data processing and retrieval. termsOfService: https://mixpeek.com/terms contact: name: Mixpeek Support url: https://mixpeek.com/contact email: info@mixpeek.com version: '0.82' servers: - url: https://api.mixpeek.com description: Production security: - BearerAuth: [] paths: /v1/features/search: post: tags: - Feature Search summary: Feature Search description: >- Search documents by vector similarity across collections. A convenience wrapper that builds an ad-hoc retriever with a single feature_search stage. operationId: feature_search_v1_features_search_post parameters: [] requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/FeatureSearchRequest' responses: '200': description: Successful Response content: application/json: schema: {} '400': description: Bad Request content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: Forbidden content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: Not Found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' '500': description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - BearerAuth: [] NamespaceHeader: [] components: schemas: FeatureSearchRequest: properties: collection_identifiers: items: type: string type: array title: Collection Identifiers description: >- Collection IDs or names to search. OPTIONAL: omit (or pass []) on standalone/BYOV namespaces to search the namespace's direct-upsert documents without naming a collection. query: $ref: '#/components/schemas/FeatureSearchQuery' description: Search query. feature_uri: type: string title: Feature Uri description: Feature URI to search against. default: mixpeek://text_extractor@v1/embedding top_k: type: integer maximum: 1000 minimum: 1 title: Top K description: Number of results to return. default: 25 filters: anyOf: - additionalProperties: true type: object - type: 'null' title: Filters description: Pre-filters to apply before search. type: object required: - query title: FeatureSearchRequest ErrorResponse: properties: success: type: boolean title: Success description: Always false for error responses default: false status: type: integer title: Status description: HTTP status code for this error error: $ref: '#/components/schemas/ErrorDetail' description: Error details payload type: object required: - status - error title: ErrorResponse description: Error response model. examples: - error: details: id: ns_123 resource: namespace message: Namespace not found type: NotFoundError status: 404 success: false HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError FeatureSearchQuery: properties: input_mode: type: string title: Input Mode description: 'Input mode: text, image, url, or vector.' default: text text: anyOf: - type: string - type: 'null' title: Text description: Text query (when input_mode=text). url: anyOf: - type: string - type: 'null' title: Url description: URL query (when input_mode=url). image: anyOf: - type: string - type: 'null' title: Image description: Base64 image (when input_mode=image). vector: anyOf: - items: type: number type: array - items: items: type: number type: array type: array - type: 'null' title: Vector description: >- Pre-computed query vector (when input_mode=vector). Either a single dense vector (list[float]) or multi-vector token embeddings (list[list[float]], e.g. ColBERT). NOTE — this field is specific to THIS convenience endpoint. In a retriever's feature_search STAGE the canonical carrier is 'value': {"input_mode": "vector", "value": [...]}. The stage also accepts 'vector' as a forgiving alias (normalized to 'value'), so the same shape works in both places. type: object title: FeatureSearchQuery ErrorDetail: properties: message: type: string title: Message description: Human-readable error message type: type: string title: Type description: Stable error type identifier (machine-readable) code: anyOf: - type: string - type: 'null' title: Code description: >- Fine-grained error code for programmatic handling (e.g., namespace_name_taken, feature_extractor_not_found). Present only when consumers may need to branch on a specific error condition. details: anyOf: - additionalProperties: true type: object - type: 'null' title: Details description: >- Optional structured details to help debugging (validation errors, IDs, etc.) type: object required: - message - type title: ErrorDetail description: Error detail model. ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type input: title: Input ctx: type: object title: Context type: object required: - loc - msg - type title: ValidationError securitySchemes: BearerAuth: type: http scheme: bearer description: >- Mixpeek API key, sent as `Authorization: Bearer mxp_sk_...`. Create one in Studio under Settings → API Keys, or with an admin key via `POST /v1/organizations/users/{user_email}/api-keys`. A missing header returns 403; an invalid or revoked key returns 401. NamespaceHeader: type: apiKey in: header name: X-Namespace description: >- Namespace id (`ns_...`), not the namespace name. This scopes the request rather than authenticating it, and it is required on every operation marked `x-mixpeek-namespace-scoped`. ````