Mammoth automatically detects your file type during upload. Each upload must be 50 MB or smaller in total, so a folder counts as one upload (see limits and quotas).
| Format | Extension | Notes |
|---|
| CSV | .csv | Most reliable for data exchange |
| TSV | .tsv | Use when data contains commas |
| PSV | .psv | Pipe-delimited, alternative to CSV/TSV |
| Excel | .xls, .xlsx | Multiple sheets supported |
| Format | Extension | Notes |
|---|
| PDF | .pdf | Text extraction, table detection |
| Plain text | .txt | Custom delimiters supported |
| XML | .xml | Converted to structured tabular data |
Compressed archives
| Format | Extension |
|---|
| ZIP | .zip |
| GZIP | .gz |
| Bzip2 | .bz2 |
| Tar | .tar |
| 7-Zip | .7z |
| Format | Extension |
|---|
| JPEG | .jpeg, .jpg |
| PNG | .png |
| TIFF | .tiff, .tif |
| HEIC | .heic, .heif |
| WebP | .webp |
CSV and TSV
- Use UTF-8 encoding for international or special characters
- Include column headers in the first row
- Use ISO date format (YYYY-MM-DD) for reliable date detection
- For banking and financial files: remove comma thousand separators—most banking portals do not accept them
- If your data contains commas within values, use TSV or wrap values in quotes
Excel
What gets imported
- All data values
- Multiple worksheets (you choose which to import)
- Data types per column
What does not get imported
- Charts and embedded images
- Macros and VBA code
Excel tips
Use the first row for column headers, avoid merged cells in data areas, and ensure consistent data types within each column.
PDF
- PDF and image files are available when enabled for your workspace, and are processed with AI-assisted extraction
- After upload, choose what to import: All content, Only tables, or a custom instruction
- Tables must have a clear, consistent structure for reliable extraction
- Complex or irregular layouts may require manual review after extraction
Compressed archives
- Mammoth automatically detects the compression format and extracts all contained files
- Each extracted file is processed according to its own format
- Use compression to upload larger datasets within the 50 MB limit
- CSV—maximum compatibility, banking integrations, simple data structures
- TSV—when your data contains comma values
- Excel—multiple related tables, multi-sheet data
- Compression—datasets approaching the 50 MB limit, multiple files in one upload
- PDF—reports with tabular data, recurring document processing
| Problem | Likely Cause | Solution |
|---|
| Data appears in a single column | Wrong delimiter detected | Specify delimiter manually in the Data Preview modal |
| Special characters show as symbols | File not UTF-8 encoded | Re-save file with UTF-8 encoding |
| Wrong data imported from Excel | Wrong worksheet selected | Choose the correct worksheet during upload |
| PDF table data incomplete | Complex or irregular layout | Review extracted data manually and clean as needed |
| Dates not recognised | Inconsistent date format | Use ISO format (YYYY-MM-DD) or define date format on upload |