> ## Documentation Index > Fetch the complete documentation index at: https://docs.ionworks.com/llms.txt > Use this file to discover all available pages before exploring further. # Upload a material property dataset > Upload a parquet or CSV file as a material property dataset. The file must contain at least the columns declared in ``columns``. All values are coerced to Float64; non-parseable cells are stored as NaN. The raw file is preserved in storage alongside the processed parquet. The ``columns`` field must be a JSON-encoded array, e.g.:: [ {"name": "c_e", "unit": "mol/L"}, {"name": "kappa", "unit": "S/m"}, {"name": "diffusivity", "unit": "m^2/s"} ] ## OpenAPI ````yaml https://api.ionworks.com/openapi.json post /material_property_datasets openapi: 3.1.0 info: title: FastAPI version: 0.1.0 servers: - url: https://api.ionworks.com description: Production security: [] paths: /material_property_datasets: post: tags: - Material Property Datasets summary: Upload a material property dataset description: >- Upload a parquet or CSV file as a material property dataset. The file must contain at least the columns declared in ``columns``. All values are coerced to Float64; non-parseable cells are stored as NaN. The raw file is preserved in storage alongside the processed parquet. The ``columns`` field must be a JSON-encoded array, e.g.:: [ {"name": "c_e", "unit": "mol/L"}, {"name": "kappa", "unit": "S/m"}, {"name": "diffusivity", "unit": "m^2/s"} ] operationId: create_material_property_dataset_material_property_datasets_post requestBody: required: true content: multipart/form-data: schema: $ref: >- #/components/schemas/Body_create_material_property_dataset_material_property_datasets_post responses: '201': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/MaterialPropertyDataset' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' components: schemas: Body_create_material_property_dataset_material_property_datasets_post: properties: file: type: string contentMediaType: application/octet-stream title: File material_id: type: string title: Material Id project_id: type: string title: Project Id name: type: string title: Name description: User-provided dataset name columns: type: string title: Columns description: 'JSON array of column specs: [{"name": "c_e", "unit": "mol/L"}, ...]' no_header: type: boolean title: No Header description: >- Set to true when the CSV has no header row. Each column spec must include source_column_index to identify its position in the file. default: false type: object required: - file - material_id - project_id - name - columns title: Body_create_material_property_dataset_material_property_datasets_post MaterialPropertyDataset: properties: material_id: type: string title: Material Id description: ID of the parent material project_id: type: string title: Project Id description: ID of the project this property is scoped to name: type: string title: Name description: User-provided dataset name, e.g. 'Electrolyte transport' columns: items: $ref: '#/components/schemas/ColumnSpec' type: array title: Columns description: All columns in the dataset with their units. id: type: string title: Id description: Unique identifier organization_id: type: string title: Organization Id description: Organization that owns this record storage_path: type: string title: Storage Path description: >- Path to the processed parquet file in the material-property-datasets bucket. original_path: anyOf: - type: string - type: 'null' title: Original Path description: >- Path to the raw original file in the material-property-datasets bucket. NULL only for records created before this field was introduced. data_version: type: integer title: Data Version description: >- Increments on every data-changing operation (file replacement or column re-processing). Downstream code can store this alongside computed results and compare against the current value to detect staleness. nan_counts: anyOf: - additionalProperties: type: integer type: object - type: 'null' title: Nan Counts description: >- Number of NaN/null values per column, keyed by display name. Computed at upload time. ``None`` for records uploaded before this field was introduced. no_header: type: boolean title: No Header description: >- True when the uploaded CSV had no header row. Column positions are mapped via ``source_column_index`` on each column spec. default: false created_by: anyOf: - type: string - type: 'null' title: Created By description: User ID of the uploader created_at: type: string format: date-time title: Created At description: Upload timestamp updated_at: type: string format: date-time title: Updated At description: Last update timestamp type: object required: - material_id - project_id - name - columns - id - organization_id - storage_path - data_version - created_at - updated_at title: MaterialPropertyDataset description: Material property dataset record as returned by the API. HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError ColumnSpec: properties: name: type: string title: Name description: Display name stored in the processed parquet unit: type: string title: Unit description: >- Physical unit, e.g. 'mol.L-1' or 'S.m-1'. Empty string for unitless quantities. default: '' source_column_index: type: integer title: Source Column Index description: >- 0-based column position in the uploaded file. The column at this position is selected and stored under ``name``. Required for all uploads regardless of whether the file has a header row. type: object required: - name - source_column_index title: ColumnSpec description: One column in a material property dataset, with its unit and role. 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 ````