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| title: Where does st.file_uploader store uploaded files and when do they get deleted? | |
| slug: /knowledge-base/using-streamlit/where-file-uploader-store-when-deleted | |
| # Where does st.file_uploader store uploaded files and when do they get deleted? | |
| When you upload a file using [`st.file_uploader`](/develop/api-reference/widgets/st.file_uploader), the data are copied to the Streamlit backend via the browser, and contained in a BytesIO buffer in Python memory (i.e. RAM, not disk). The data will persist in RAM until the Streamlit app re-runs from top-to-bottom, which is on each widget interaction. If you need to save the data that was uploaded between runs, then you can [cache](/develop/concepts/architecture/caching) it so that Streamlit persists it across re-runs. | |
| As files are stored in memory, they get deleted immediately as soon as they’re not needed anymore. | |
| This means Streamlit removes a file from memory when: | |
| - The user uploads another file, replacing the original one | |
| - The user clears the file uploader | |
| - The user closes the browser tab where they uploaded the file | |
| Related forum posts: | |
| - https://discuss.streamlit.io/t/streamlit-sharing-fileupload-where-does-it-go/9267 | |
| - https://discuss.streamlit.io/t/how-to-update-the-uploaded-file-using-file-uploader/13512/ | |