Plagx Preflight for Python

A free academic writing tool by Plagiarism Checker X.

Plagx Preflight for Python is a free, open-source draft checker for Python. Use it as an essay checker before you submit: it checks the word count and structure, matches in-text citations against the reference list, and gives punctuation and basic grammar suggestions plus readability stats.

• No dependencies, works offline: your text never leaves the machine
• Python 3.9+, typed
• APA and MLA citation checks
• Command line with JSON output and CI-friendly exit codes
• Results identical to the JavaScript version, offsets included

Try the live demo →

Developer downloads: PyPI · npm · Packagist · Docker Hub · GitHub

Plagx Preflight is a free academic writing utility by Plagiarism Checker X. It checks length, structure, references, punctuation and basic grammar, and every result is a suggestion. Plagiarism checking and AI-generated text detection are available in Plagiarism Checker X, linked at the end of this page.

Install

pip install plagx-preflight

Quick start

from plagx_preflight import check_draft

result = check_draft(text, min_words=1500, max_words=2000, style="apa",
                     required_headings=["Introduction", "Conclusion"])

result["stats"]
# {'words': 1620, 'sentences': 84, 'paragraphs': 12, 'characters': 9811,
#  'readingTimeMinutes': 9, 'fleschReadingEase': 48.2}

for issue in result["issues"]:
    print(f"{issue['line']}:{issue['column']} {issue['level']} {issue['message']}")
# 5:14 warning Suggestion: "the the" looks like a repeated word.

Command line

plagx-preflight check essay.txt --min-words 1500 --max-words 2000 --style apa
plagx-preflight check essay.md --json
plagx-preflight stats essay.txt
cat essay.txt | plagx-preflight check -
python -m plagx_preflight --help

Exit codes: 0 no errors, 1 errors found (with --strict, warnings too), 2 usage or input error. Accepts .txt and .md.

API

check_draft(text, *, min_words=None, max_words=None, style="apa", checks=None, required_headings=()) returns a dict with stats, errors, warnings, infos and issues. Each issue has level, code, message, start, end, line, column, text and suggestion. Issues are sorted by position.

start, end and column count UTF-16 code units, like JavaScript, so results match the other Plagx Preflight libraries exactly. For Python string slicing, use text or line and column (they differ only after emoji and other characters outside the Basic Multilingual Plane).

Helpers: count_words(text), split_sentences(text), find_citations(text, style), VERSION, CHECKS. Invalid options raise ValueError.

Checks

Good to know

• Every result is a suggestion. The grammar rules are deliberately conservative, so they miss some mistakes rather than flag correct text.
• The reference list starts at a heading such as References, Bibliography or Works Cited. It is excluded from the word count and from the punctuation and grammar checks.

Development

pip install -e . pytest
pytest

tests/parity/expected.json and tests/fixtures/ come from the JavaScript reference (npm run parity in plagx-preflight). Every case must match exactly. src/plagx_preflight/_unicode.py holds Unicode letter classes generated from the JavaScript regex engine (node scripts/build_unicode.mjs), because Python's re module has no \p{...}.

Plagx Preflight - Free Draft & Grammar Checker

An open-source writing utility for students, researchers and developers. Check length, structure, citations, punctuation and basic grammar before you submit.

Developed by Plagiarism Checker X.

Plagx Preflight gives writing suggestions; it does not detect plagiarism or AI-generated text. For full document checks, explore Plagiarism Checker X and its AI Content Detector.

License

MIT © Plagiarism Checker X