Upload File

Upload and create a new file in Extend. This endpoint accepts file contents and registers them as a File in Extend, which can be used for [running workflows](https://docs.extend.ai/2026-02-09/api-reference/endpoints/workflow/create-workflow-run), [creating evaluation set items](https://docs.extend.ai/2026-02-09/api-reference/endpoints/evaluation/create-evaluation-set-item), [parsing](https://docs.extend.ai/2026-02-09/api-reference/endpoints/parse/parse-file), etc. If an uploaded file is detected as a Word or PowerPoint document, it will be automatically converted to a PDF. Supported file types can be found [here](https://docs.extend.ai/2026-02-09/general/supported-file-types). This endpoint requires multipart form encoding. Most HTTP clients will handle this encoding automatically (see the examples).