> ## Documentation Index > Fetch the complete documentation index at: https://docs.canary.effectiveai.app/llms.txt > Use this file to discover all available pages before exploring further. # Read a bounded chunk of existing extracted text > Read-only optional representation for persistent files with an existing extraction in versioned storage, including SERFF. Never starts acquisition, OCR, extraction or materialization. Rechecks content access and export policy on every request. Reads at most maxBytes + 128 text bytes from storage; JSON is below 400 KiB including escaping. Source-page mapping is not inferred. A changed revision requires restarting without a cursor. ## OpenAPI ````yaml /openapi.json get /files/{fileId}/text openapi: 3.0.3 info: title: Effective API version: 2.0.0 description: The public Effective REST API. Authenticate using an Effective API key. servers: - url: https://canary.effectiveai.app/api/v2 description: Canary security: - bearerAuth: [] paths: /files/{fileId}/text: get: tags: - Files summary: Read a bounded chunk of existing extracted text description: >- Read-only optional representation for persistent files with an existing extraction in versioned storage, including SERFF. Never starts acquisition, OCR, extraction or materialization. Rechecks content access and export policy on every request. Reads at most maxBytes + 128 text bytes from storage; JSON is below 400 KiB including escaping. Source-page mapping is not inferred. A changed revision requires restarting without a cursor. operationId: readFileText parameters: - schema: type: string format: uuid required: true name: fileId in: path - schema: type: integer minimum: 4 maximum: 65536 default: 16384 description: >- Maximum UTF-8 bytes of text per response, 4–65536 (default 16384). Character boundaries may shorten a chunk. Repeat unchanged with cursor. required: false description: >- Maximum UTF-8 bytes of text per response, 4–65536 (default 16384). Character boundaries may shorten a chunk. Repeat unchanged with cursor. name: maxBytes in: query - schema: type: string minLength: 1 maxLength: 128 description: >- Opaque nextCursor. Fixed 24-hour lifetime; bound to caller scope, file, maxBytes and text revision. required: false description: >- Opaque nextCursor. Fixed 24-hour lifetime; bound to caller scope, file, maxBytes and text revision. name: cursor in: query responses: '200': description: A revision-bound text chunk with byte location and continuation. content: application/json: schema: $ref: '#/components/schemas/V2FileText' '400': description: >- invalid_request or invalid_cursor. For invalid, expired, differently bound or changed-revision cursors, restart without cursor. content: application/json: schema: $ref: '#/components/schemas/V2CodedError' '401': description: Authentication required. content: application/json: schema: $ref: '#/components/schemas/V2CodedError' '403': description: 'download_restricted: visible file is restricted from content export.' content: application/json: schema: $ref: '#/components/schemas/V2CodedError' '404': description: 'not_found: file is missing or inaccessible.' content: application/json: schema: $ref: '#/components/schemas/V2CodedError' '409': description: >- text_unavailable: no supported, revision-bound UTF-8 extraction exists. Try the original download; this request starts no work. content: application/json: schema: $ref: '#/components/schemas/V2CodedError' '500': description: Unexpected server error. content: application/json: schema: $ref: '#/components/schemas/V2CodedError' '503': description: >- temporarily_unavailable: storage or continuation dependency failed. Retry the same request after Retry-After seconds. content: application/json: schema: $ref: '#/components/schemas/V2CodedError' security: - bearerAuth: [] components: schemas: V2FileText: type: object properties: fileId: type: string format: uuid textRevision: type: string maxLength: 68 description: >- Opaque identity of this extracted-text revision, distinct from an original-file version. Changed text invalidates continuation. versionId: type: string nullable: true description: >- Source file version that produced this extraction, or null when unproven. Currently null; never inferred from the current download. text: type: string maxLength: 65536 description: >- Existing UTF-8 extracted text, at most maxBytes UTF-8 bytes. Empty available text is a successful terminal response. Page markers, if present, remain in text. location: type: object properties: startOffsetBytes: type: integer minimum: 0 description: Inclusive zero-based UTF-8 byte offset in this text revision. endOffsetBytes: type: integer minimum: 0 description: >- Exclusive UTF-8 byte offset. Source-page coordinates are not verified by this representation. required: - startOffsetBytes - endOffsetBytes nextCursor: type: string nullable: true description: >- Continue with the same file and maxBytes, or null at the end. Retry the same request safely; deduplicate by revision and start offset. required: - fileId - textRevision - versionId - text - location - nextCursor V2CodedError: allOf: - $ref: '#/components/schemas/V2Error' - type: object properties: code: type: string minLength: 1 description: Stable error code. Clients must tolerate unknown future codes. details: type: array items: type: object properties: location: type: string enum: - path - query - header - body path: type: array items: type: string maxLength: 64 maxItems: 12 code: type: string enum: - required - invalid_type - invalid_value - unknown_field message: type: string minLength: 1 maxLength: 200 required: - location - path - code - message minItems: 1 maxItems: 20 description: Bounded safe validation issues; may omit some invalid fields. requestId: type: string minLength: 1 maxLength: 128 description: >- Existing server correlation for this HTTP attempt, when available. required: - code V2Error: type: object properties: error: type: string minLength: 1 description: Human-readable explanation of the failure. required: - error securitySchemes: bearerAuth: type: http scheme: bearer description: 'Effective API key. Send Authorization: Bearer sk-eai-...' ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.