> ## Documentation Index > Fetch the complete documentation index at: https://dialnexa.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Upload Knowledge Base Document > Upload a knowledge base document to store and index a PDF or TXT file for agent retrieval. Changes state - verify before retry Upload a knowledge base document to store and index a PDF or TXT file for agent retrieval. The knowledge base must already exist in the authenticated workspace. ## Before you begin * [Create a knowledge base](/docs/api-reference/v1/knowledge-base/create) and keep its `kb_` ID. * Prepare a PDF or TXT file no larger than 100 MB (104857600 bytes). * Choose a non-empty title unique within that knowledge base. Each knowledge base allows 25 non-deleted documents. ## Upload Knowledge Base Document Request ```bash theme={null} curl https://api.dialnexa.com/v1/documents/upload \ -H "Authorization: Bearer $DIALNEXA_API_KEY" \ -F "knowledge_base_id=kb_abc123" \ -F "title=Support FAQ" \ -F "file=@support-faq.txt;type=text/plain" ``` Optional `description` and `source` fields describe the file. Let your HTTP client set the multipart boundary. ## Verify the result A `201` response contains the created document in `data`, including its ID, title, knowledge base ID, file type, and size. [List Knowledge Base Documents](/docs/api-reference/v1/knowledge-base/documents) and confirm the file is present. Attach the knowledge base to the intended agent and ask a test question covered by the document. ## Errors and recovery | Status | Recovery | | ------ | -------------------------------------------------------------------------------- | | `400` | Check required fields, PDF/TXT format, and the 25-document limit. | | `401` | Correct the API key. | | `404` | Select a knowledge base in this workspace. | | `409` | A document with the same title exists. Inspect it before choosing another title. | | `413` | Reduce the file below the 100 MB limit. | | `500` | Parsing, storage, or indexing failed. Inspect the document list before retrying. | Uploading stores a file and indexes its content. It is not an idempotent replacement operation. After an uncertain response, list documents before retrying; changing the title can create duplicate content. To replace an existing document, use [dashboard document management](/docs/knowledge-base/managing-documents). ## Related endpoints * [List Knowledge Base Documents](/docs/api-reference/v1/knowledge-base/documents) * [Knowledge base file limits](/docs/knowledge-base/documents-and-file-limits) ## OpenAPI ````yaml POST /v1/documents/upload openapi: 3.0.0 info: title: DialNexa API description: Public `/v1` REST API for the DialNexa voice AI platform. version: 1.0.0 servers: - url: https://api.dialnexa.com description: DialNexa production API security: - bearer: [] tags: - name: Agents - name: Batch Calls - name: Calls - name: Knowledge Base - name: Languages - name: LLMs - name: Phone Numbers - name: Transcribers - name: Webhooks - name: Voices - name: Workflows - name: Workflow Leads - name: Authentication - name: Agent Builder paths: /v1/documents/upload: post: tags: - Knowledge Base summary: Upload Knowledge Base Document description: >- Parses, stores, and indexes one PDF or TXT document in a knowledge base owned by the authenticated workspace. Maximum 100 MB per document and 25 non-deleted documents per knowledge base. Document titles must be unique within the knowledge base. operationId: uploadKnowledgeBaseDocument parameters: [] requestBody: required: true content: multipart/form-data: schema: type: object properties: file: type: string format: binary description: PDF or TXT file, at most 100 MB (104857600 bytes). title: type: string minLength: 1 knowledge_base_id: type: string description: type: string source: type: string required: - file - title - knowledge_base_id examples: request: value: file: support-faq.txt title: Support FAQ knowledge_base_id: kb_abc123def45678 responses: '201': description: Successful response. content: application/json: schema: type: object properties: success: type: boolean error: type: boolean statusCode: type: integer message: type: string data: $ref: '#/components/schemas/KnowledgeBaseDocument' timestamp: type: string format: date-time required: - success - error - statusCode - message - data - timestamp examples: success: value: success: true error: false statusCode: 201 message: Success data: id: abc123def45678 title: Support FAQ knowledge_base_id: abc123def45678 document_type: txt file_size: 1 is_deleted: false timestamp: '2026-09-07T06:00:00.000Z' '400': description: Missing fields, unsupported file, or document count limit reached. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: error: value: statusCode: 400 message: >- Missing fields, unsupported file, or document count limit reached. error: Bad Request '401': description: Missing or invalid API key. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: error: value: statusCode: 401 message: Missing or invalid API key. error: Unauthorized '404': description: Knowledge base not found in this workspace. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: error: value: statusCode: 404 message: Knowledge base not found in this workspace. error: Not Found '409': description: A document with this title already exists. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: error: value: statusCode: 409 message: A document with this title already exists. error: Conflict '413': description: File exceeds the 100 MB upload limit. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: error: value: statusCode: 413 message: File exceeds the 100 MB upload limit. error: Payload Too Large '500': description: Document parsing, storage, or indexing failed. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: error: value: statusCode: 500 message: Document parsing, storage, or indexing failed. error: Internal Server Error security: - bearer: [] components: schemas: KnowledgeBaseDocument: type: object properties: id: type: string title: type: string knowledge_base_id: type: string description: type: string content: type: string source: type: string document_type: type: string file_path: type: string file_size: type: number description: File size in KB (1024 bytes). is_deleted: type: boolean ErrorResponse: type: object properties: statusCode: type: integer example: 400 message: oneOf: - type: string - type: array items: type: string example: phone_number must be a valid E.164 phone number error: type: string example: Bad Request required: - statusCode - message - error securitySchemes: bearer: scheme: bearer type: http ````