> ## Documentation Index > Fetch the complete documentation index at: https://docs.mangrovesystems.com/llms.txt > Use this file to discover all available pages before exploring further. # Run a data feed transformation against a test input > Runs a Python transformation script against the data feed's stored test input (or a file uploaded in the same request) and returns up to 3 preview rows. No events or runs are created. Real Python tracebacks are surfaced on failure, so callers can iterate write → test → save without the app's testing console. The script in `script_content` is what runs; `event_type_slug` must name an event type with an active transformation on the data feed. If a `file` is uploaded, it replaces the data feed's stored test input. Otherwise the stored test input is used; if none exists, the request returns 422. Requires the `read:data_feed` token scope. ## OpenAPI ````yaml POST /data_feeds/{data_feed_friendly_id}/test_transformation openapi: 3.1.0 info: title: Mangrove - API version: 1.1.0 description: > ## Filtering and sorting List endpoints that accept `filter` take one query parameter per condition, written `filter[field][comparator]=value`, for example `filter[name][contains]=North`. The comparators are `eq`, `neq`, `gt`, `geq`, `lt`, `leq` and `contains`, and `filter[field]=value` is short for `eq`. Conditions combine with AND. `contains` matches part of the value, is case-sensitive, and applies only to text fields. An unknown field or comparator, a value that doesn't fit the field's type, or a list or object as the value returns 400 with a message naming the problem. Each list operation names its filterable fields; some take only `eq`, and say so. `sort` takes a comma-separated list of fields, for example `sort=-created_at,name`. Each field sorts ascending, or descending with a `-` prefix. Unknown sort fields are ignored. Sorting by `id` orders by the record's internal ID, not its friendly ID. Each list operation names its sortable fields. servers: - url: https://app.gomangrove.com/api/v1 security: - sec0: [] paths: /data_feeds/{data_feed_friendly_id}/test_transformation: post: tags: - Data Ingestion summary: Run a data feed transformation against a test input description: > Runs a Python transformation script against the data feed's stored test input (or a file uploaded in the same request) and returns up to 3 preview rows. No events or runs are created. Real Python tracebacks are surfaced on failure, so callers can iterate write → test → save without the app's testing console. The script in `script_content` is what runs; `event_type_slug` must name an event type with an active transformation on the data feed. If a `file` is uploaded, it replaces the data feed's stored test input. Otherwise the stored test input is used; if none exists, the request returns 422. Requires the `read:data_feed` token scope. operationId: test-data-feed-transformation parameters: - $ref: '#/components/parameters/DataFeedFriendlyId' requestBody: required: true content: multipart/form-data: schema: type: object required: - script_content - event_type_slug properties: script_content: type: string description: The Python transformation script to execute example: |- for row in rows: events.append({'date': row['Date'], 'value': float(row['Amount'])}) event_type_slug: type: string description: >- The slug of an event type with an active transformation on the data feed example: combustion file: type: string format: binary description: >- Optional CSV or Excel file to use as the test input. Replaces the data feed's stored test input when provided. Max 50MB. encoding: file: contentType: >- text/csv, application/vnd.ms-excel, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel.sheet.macroEnabled.12 responses: '200': description: Transformation ran successfully content: application/json: schema: type: object required: - events properties: events: type: array description: Up to 3 preview rows produced by the transformation items: type: object additionalProperties: true test_input: $ref: '#/components/schemas/DataFeedTestInput' example: events: - date: '2024-01-01' value: 100 unit: tCO2e test_input: id: 42 filename: emissions_2024.csv content_type: text/csv file_size: 2048 uploaded_at: '2026-05-04T10:30:00Z' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': description: Data feed, event type, or transformation not found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: dataFeedMissing: value: errors: - message: Pipeline not found eventTypeMissing: value: errors: - message: Event type 'combustion' not found transformationMissing: value: errors: - message: Transformation not found for event type 'combustion' '422': description: > The transformation could not be executed. Either the request was invalid (a missing parameter, a rejected file, no test input available) or the Python script raised an exception. On a script failure, `errors` carries the humanized message, `traceback` the full Python traceback (or null when the failure was not a Python exception), and `test_input` the input it ran against. content: application/json: schema: allOf: - $ref: '#/components/schemas/ErrorResponse' - type: object properties: traceback: type: - string - 'null' test_input: $ref: '#/components/schemas/DataFeedTestInput' examples: missingScript: summary: Missing script_content parameter value: errors: - message: script_content is required missingSlug: summary: Missing event_type_slug parameter value: errors: - message: event_type_slug is required invalidFile: summary: Uploaded file is not CSV or Excel value: errors: - message: Only CSV and Excel files are accepted missingTestInput: summary: No stored test input and none uploaded value: errors: - message: Either upload a file or ensure a test input exists traceback: null test_input: null pythonError: summary: Python exception raised by the script value: errors: - message: 'KeyError: ''amount'' (line 3)' traceback: |- Traceback (most recent call last): File "", line 3, in transform KeyError: 'amount' test_input: id: 42 filename: emissions_2024.csv content_type: text/csv file_size: 2048 uploaded_at: '2026-05-04T10:30:00Z' components: parameters: DataFeedFriendlyId: name: data_feed_friendly_id in: path required: true description: The data feed's friendly ID (e.g. `datafd_aBcD1234eFgH5678`). schema: type: string schemas: DataFeedTestInput: type: - object - 'null' description: The stored test input the script ran against. properties: id: type: integer filename: type: string content_type: type: string file_size: type: integer uploaded_at: type: string format: date-time ErrorResponse: type: object required: - errors properties: errors: type: array items: type: object required: - message properties: message: type: string description: Human-readable error message field: type: string description: Attribute the error applies to (validation errors only) code: type: string description: Machine-readable error code (validation errors only) blocking: type: array description: >- Bounded preview of the records blocking a destroy (blocked-destroy errors only) items: $ref: '#/components/schemas/DeletionBlockingRecord' blocking_count: type: integer description: >- Total count of records blocking a destroy (blocked-destroy errors only) config_key: type: string description: >- The data feed source config setting to fix, when the error is on `config` (data feed source validation errors only) count: type: number description: >- The limit or comparison value the failed validation checked against, e.g. a maximum length or a numeric bound (validation errors only, when the validation has one) value: description: >- The rejected value, e.g. on an inclusion or uniqueness failure (validation errors only, when the validation reports one) DeletionBlockingRecord: type: object required: - type properties: type: type: string friendly_id: type: string name: type: - string - 'null' description: >- Display label, and the only identifier for records that have no friendly_id responses: Unauthorized: description: >- The API token is missing, invalid or expired. The body is empty, except for an expired token, which returns the error below. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: errors: - message: API token has expired Forbidden: description: >- The token lacks the scope the operation's description names, or a condition the description states applies, such as a feature that isn't enabled for your account. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: errors: - message: You are not authorized to perform this action securitySchemes: sec0: type: apiKey in: header name: Authorization x-bearer-format: '' ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.