> ## Documentation Index > Fetch the complete documentation index at: https://docs.superdocs.app/llms.txt > Use this file to discover all available pages before exploring further. # Upload .docx/PDF/HTML/MD/RTF as the active editable document with chunk-ID structural editing. > Parses the file into structured HTML where every paragraph, heading, table, row, and cell has a unique chunk ID, enabling the AI to make targeted structural edits via chat ("remove row 3 of the pricing table" works). Tables, borders, shading, alternating row colors, fonts, and inline styling are preserved on edit and export. Also works for AI-generated content: if you've drafted an outline or partial document in your context, upload it here as the working doc, then use chat to fill in the rest. This is also the reliable way to REPLACE a session's document with exact content you already hold — the upload is a verbatim load, so it can never come back paraphrased or placeholder-shaped the way asking chat to re-type it can. When you pass a session_id the response is compact by default (metadata only — pass return_html=true for the full parsed HTML); the document is loaded into the session and you edit it via chat. For files >100KB, prefer request_upload_url (pre-signed URL flow) to avoid token bloat from base64 through the agent context. Supported formats: .pdf, .docx, .txt, .rtf, .md, .html, .htm. Max 50 MB validated; note the hosted transport layer caps any REQUEST BODY at ~32 MB and rejects larger ones at the gateway with an HTML (not JSON) error — base64 inflates content ~33%, so inline uploads are reliable up to ~20 MB of file bytes; beyond that use request_upload_url (pre-signed flow, up to 100 MB). ## OpenAPI ````yaml /openapi.json post /v1/documents/upload-base64 openapi: 3.1.0 info: title: Universal Document AI API description: AI-powered document editing with multi-tenant organization support version: 2.0.0 servers: [] security: [] paths: /v1/documents/upload-base64: post: tags: - v1 - mcp - documents summary: >- Upload .docx/PDF/HTML/MD/RTF as the active editable document with chunk-ID structural editing. description: >- Parses the file into structured HTML where every paragraph, heading, table, row, and cell has a unique chunk ID, enabling the AI to make targeted structural edits via chat ("remove row 3 of the pricing table" works). Tables, borders, shading, alternating row colors, fonts, and inline styling are preserved on edit and export. Also works for AI-generated content: if you've drafted an outline or partial document in your context, upload it here as the working doc, then use chat to fill in the rest. This is also the reliable way to REPLACE a session's document with exact content you already hold — the upload is a verbatim load, so it can never come back paraphrased or placeholder-shaped the way asking chat to re-type it can. When you pass a session_id the response is compact by default (metadata only — pass return_html=true for the full parsed HTML); the document is loaded into the session and you edit it via chat. For files >100KB, prefer request_upload_url (pre-signed URL flow) to avoid token bloat from base64 through the agent context. Supported formats: .pdf, .docx, .txt, .rtf, .md, .html, .htm. Max 50 MB validated; note the hosted transport layer caps any REQUEST BODY at ~32 MB and rejects larger ones at the gateway with an HTML (not JSON) error — base64 inflates content ~33%, so inline uploads are reliable up to ~20 MB of file bytes; beyond that use request_upload_url (pre-signed flow, up to 100 MB). operationId: upload_document_base64 parameters: - name: authorization in: header required: false schema: anyOf: - type: string - type: 'null' title: Authorization requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/Base64UploadRequest' responses: '200': description: Successful Response content: application/json: schema: {} '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' security: - HTTPBearer: [] components: schemas: Base64UploadRequest: properties: filename: type: string maxLength: 512 title: Filename description: >- Original filename with extension (e.g. 'contract.pdf'). Used for file type detection. file_base64: type: string maxLength: 50000000 title: File Base64 description: Base64-encoded file content. session_id: anyOf: - type: string maxLength: 256 - type: 'null' title: Session Id description: Session ID. Auto-generated if not provided. return_html: type: boolean title: Return Html description: >- With a session_id: false (default) returns compact metadata only (chunks_count, version_id, page_setup) — the document is loaded into the session and you edit it via chat, keeping your context small; true returns the full parsed HTML inline. Ignored on the convert-only path (no session_id), which always returns the converted html. default: false type: object required: - filename - file_base64 title: Base64UploadRequest description: JSON request body for base64-encoded file uploads. HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type type: object required: - loc - msg - type title: ValidationError securitySchemes: HTTPBearer: type: http scheme: bearer ````