A python-pptx alternative for editing existing PowerPoint decks

The same edit script with one import changed

import zipfile

from wolfppt import Presentation  # was: from pptx import Presentation

prs = Presentation("monthly_review.pptx")
for slide in prs.slides:
    for shape in slide.shapes:
        if not shape.has_text_frame:
            continue
        for paragraph in shape.text_frame.paragraphs:
            for run in paragraph.runs:
                if "{{month}}" in run.text:
                    run.text = run.text.replace("{{month}}", "September")

table = next(s for s in prs.slides[1].shapes if s.has_table).table
table.cell(1, 1).text = "$4.2M"
prs.save("monthly_review_updated.pptx")

with zipfile.ZipFile("monthly_review.pptx") as before, zipfile.ZipFile("monthly_review_updated.pptx") as after:
    assert before.namelist() == after.namelist()
    print([n for n in before.namelist() if before.read(n) != after.read(n)])
# ['ppt/slides/slide1.xml', 'ppt/slides/slide2.xml']

The script replaces a placeholder in each run that holds it, writes a value into a table cell, and saves a new file. The check at the end compares the package before and after: only the two slide parts that hold edits differ, and the part list is identical. Masters, layouts, themes, media, and notes keep their original bytes.

When python-pptx fits

• You generate a new deck from code, from a template of layouts, or from a data set.
• You need a python-pptx call that the WolfPPT facade does not list. The facade covers a documented subset, so check the compatibility matrix for each call your script relies on.
• The saved file does not need to keep unedited parts as they were.

What WolfPPT adds for decks that already exist

• Untouched parts stay untouched. Saving rewrites only the parts that hold your edits. Parts WolfPPT has no schema for, such as vendor extensions, are copied through byte-for-byte.
• Guarded edits. Mutation guards refuse an unsafe edit instead of writing it.
• Familiar names. An existing python-pptx edit script usually needs only its import changed, as in the sample above.
• Free to use. The public WolfPPT release is MIT-licensed, including commercial use.

A published example edits one five-slide board deck with python-pptx and with the wolf command, which is the Wolf runtime and not the WolfPPT Python package. python-pptx rewrote 45 of the deck's 54 package parts, and Wolf rewrote 3. Both result decks are linked, along with the part-by-part list. It is one deck, so test your own files before you rely on it. See the side-by-side example on wolfsdk.com.

Limitations

• A placeholder that PowerPoint split across several runs appears as separate run texts, so the loop above matches a placeholder only when one run holds all of it.
• Setting shape.text rewrites the whole text body as newline-separated paragraphs. Assign run.text when formatting inside the shape must stay intact.
• The public MIT package edits decks and does not render them. To turn a deck into PDF or PNG, see Convert PPTX to PDF in Python.
• Chart edits use python-pptx's chart data classes, so install both packages for that task. See update chart data in an existing deck.

Review the WolfPPT compatibility matrix

Install WolfPPT

The public WolfPPT release is MIT-licensed and free, including commercial use.

pip install wolfppt

PyPI wheels cover CPython 3.11 to 3.14 on Linux x86_64 and aarch64 and on macOS arm64. Source, tests, and the full facade reference live at github.com/wolfiesch/wolfppt-oss.

Related tasks

• Update text in an existing PowerPoint deck with Python
• Update a table in an existing PowerPoint deck with Python
• Update chart data in an existing PowerPoint deck with Python
• Convert PPTX to PDF in Python without PowerPoint or LibreOffice
• A python-pptx alternative for editing existing PowerPoint decks

Cost

WolfPPT has no paid plan. The WolfPPT home page lists the supported tasks, and the pricing page covers the other WolfSDK engines.