Plagiarism Checker

🔎 Check text for matching sources

Plagiarism Checker helps writers, editors, teachers, and content teams review one text or text-bearing document. It returns a plagiarism score, sentence totals, matched passages, source links, and a plain risk summary for review.

Compare a draft with public web and academic sources, then check any reference files you provide. Long text is handled as one report, but the Actor does not promise to find every match.

• Use a Plagiarism Checker to check pasted text against public web sources.
• Use a Text Plagiarism Checker to review an article, essay, or draft before you publish it.
• Use a Website Plagiarism Checker to check a public page's text for matching passages.
• Use a Source Match Checker to review the input and source passages behind a match.
• Get a clear plagiarism report with a score, risk level, and matched sources.
• Use a Reference Document Comparison to compare your text with files you provide.

📊 See scores and source evidence

Each successful run saves one report to the Apify dataset. You get a percentage score, a low, medium, or high risk summary, sentence counts, matched sources, matched passages, and optional reference-file comparisons.

Each source is listed once, with its matched passages under it. Authors, publisher, dates, and scholarly IDs appear when the source provides them.

▶️ Check a text or document

1. Choose Plain text or Document file as the Target.
2. Paste your text or upload one text-bearing file.
3. Optional: upload reference files for a direct comparison.
4. Start the Actor and open the default dataset.

The document fields accept TXT, Markdown, HTML, PDF, and DOCX files. PDF files must contain text. Scanned or image-only PDFs need OCR before checking, which this Actor does not provide.

⚙️ Input

Choose Plain text or Document file as the Target. The other target field is ignored. Reference files are optional and work with either choice.

Input fields

Field	Type	What it does
target	string	Chooses text for pasted text or document for one document file.
text	string	Holds the pasted text when target is text.
document	string	Holds one TXT, Markdown, HTML, PDF, or DOCX file when target is document.
referenceDocuments	array of strings	Holds optional TXT, Markdown, HTML, PDF, or DOCX files for direct comparison. The report gives one similarity percent per file.

Only the field for the chosen Target is used. Reference files are optional.

Example input

{
  "target": "text",
  "text": "The quick brown fox jumps over the lazy dog. This sentence contains all 26 letters of the English alphabet. It is commonly used for touch-typing practice. It is also used to test typewriters and computer keyboards."
}

🧾 Output

Each successful report uses one dataset shape. Optional source metadata appears when known, and referenceComparisons contains one entry for each supplied reference file.

Output fields

Field	Type	What it does
plagiarismPercent	number	Share of checked sentences with a found match, from 0 to 100.
risk	object	Holds the risk level and its plain-language explanation.
risk.level	string	low, medium, or high risk level.
risk.explanation	string	Explains the reported risk level.
sentenceSummary	object	Holds the total, matched, and unique sentence counts.
sentenceSummary.total	integer	Number of sentences checked.
sentenceSummary.matched	integer	Number of sentences with a found match.
sentenceSummary.unique	integer	Number of sentences with no found match.
sources	array of objects	Matched web and academic sources, with one source entry per source.
sources[].sourceType	string	web or academic.
sources[].title	string	Title of the matched page or work.
sources[].url	string	Link to the matched source.
sources[].authors	array of strings	Source authors when known.
sources[].publisher	string	Source publisher when known.
sources[].publishedDate	date string	Source publication date when known, as YYYY-MM-DD.
sources[].identifiers	object	Known scholarly identifiers when available.
sources[].identifiers.doi	string	Digital Object Identifier when available.
sources[].identifiers.pmid	string	PubMed identifier when available.
sources[].identifiers.arxivId	string	arXiv paper identifier when available.
sources[].identifiers.issn	string	Journal or series identifier when available.
sources[].matches	array of objects	Matched passages for this source.
sources[].matches[].inputPassage	string	Matched passage from the checked content.
sources[].matches[].sourcePassage	string	Matching passage from the source.
sources[].matches[].similarityPercent	number	Strength of this passage match, from 0 to 100.
referenceComparisons	array of objects	Similarity results for the supplied reference documents.
referenceComparisons[].documentName	string	Name of the reference document.
referenceComparisons[].similarityPercent	number	Share of checked content similar to that reference, from 0 to 100.

Each source is listed once, with its matched passages under it. Optional source fields appear only when the source provides them.

Example report

{
  "plagiarismPercent": 50,
  "risk": {
    "level": "medium",
    "explanation": "Some checked sentences match public sources and should be reviewed."
  },
  "sentenceSummary": {
    "total": 4,
    "matched": 2,
    "unique": 2
  },
  "sources": [
    {
      "sourceType": "web",
      "title": "The Quick Brown Fox Jumps Over the Lazy Dog – Meaning, Origin ...",
      "url": "https://www.thehistoryofenglish.com/the-quick-brown-fox-jumps-over-the-lazy-dog",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "What you can say in place of ‘The quick brown fox jumps over the lazy dog’.",
          "similarityPercent": 72
        }
      ]
    },
    {
      "sourceType": "web",
      "title": "The quick brown fox jumps over the lazy dog - Idioms by The ...",
      "url": "https://idioms.thefreedictionary.com/the+quick+brown+fox+jumps+over+the+lazy+dog",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "What does the quick brown fox jumps over the lazy dog expression mean?",
          "similarityPercent": 81.82
        }
      ]
    },
    {
      "sourceType": "web",
      "title": "Pangram - Wikipedia",
      "url": "https://en.wikipedia.org/wiki/Pangram",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "The best-known English pangram is \"The quick brown fox jumps over the lazy dog\".",
          "similarityPercent": 75
        }
      ]
    },
    {
      "sourceType": "web",
      "title": "the quick brown fox jumps over the lazy dog",
      "url": "https://idioms.thefreedictionary.com/quick+brown+fox+jumps+over+the+lazy+dog",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "What does quick brown fox jumps over the lazy dog expression mean?",
          "similarityPercent": 76.19
        }
      ]
    },
    {
      "sourceType": "academic",
      "title": "The quick brown fox jumps over a lazy dog",
      "url": "http://www.cqvip.com/QK/82426X/198201/1002778566.html",
      "authors": [
        "孟武"
      ],
      "publisher": "现代外语",
      "publishedDate": "1982-01-01",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "句子是The quick brown fox jumps over a lazy dog.(",
          "similarityPercent": 77.78
        }
      ]
    },
    {
      "sourceType": "academic",
      "title": "The quick, brown fox jumps over a lazy dog",
      "url": "https://demo.ojsplus.com/index.php/demo1/article/view/13",
      "authors": [
        "administrator administrator"
      ],
      "publishedDate": "2020-06-17",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "The quick, brown fox jumps over a lazy dog.",
          "similarityPercent": 88.89
        }
      ]
    },
    {
      "sourceType": "academic",
      "title": "Quote Post Format",
      "url": "https://turismo.dlfroma.it/quote-post-format/",
      "authors": [
        "Davide"
      ],
      "publishedDate": "2016-06-06",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "The quick, brown fox jumps over a lazy dog.",
          "similarityPercent": 88.89
        }
      ]
    },
    {
      "sourceType": "academic",
      "title": "Aside Post Format",
      "url": "https://turismo.dlfroma.it/aside-post-format/",
      "authors": [
        "Davide"
      ],
      "publishedDate": "2016-06-06",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "The quick, brown fox jumps over a lazy dog.",
          "similarityPercent": 88.89
        }
      ]
    },
    {
      "sourceType": "academic",
      "title": "Aside Post Format",
      "url": "https://dlfroma.it/blog/2016/06/06/aside-post-format/",
      "authors": [
        "julia l"
      ],
      "publishedDate": "2016-06-06",
      "matches": [
        {
          "inputPassage": "The quick brown fox jumps over the lazy dog.",
          "sourcePassage": "The quick, brown fox jumps over a lazy dog.",
          "similarityPercent": 88.89
        }
      ]
    },
    {
      "sourceType": "web",
      "title": "The Quick Brown Fox… | EnglishClub",
      "url": "https://www.englishclub.com/efl/jo/curiosities/the-quick-brown-fox/",
      "matches": [
        {
          "inputPassage": "This sentence contains all 26 letters of the English alphabet.",
          "sourcePassage": "This sentence contains all 26 letters of the English alphabet and is (was?)",
          "similarityPercent": 86.96
        }
      ]
    }
  ],
  "referenceComparisons": []
}

No found match means sources is empty and the score may be 0. A score is evidence for review, not a ruling about intent or ownership. Public-source access can vary, so the Actor does not promise exhaustive coverage.

💳 Pricing

This Actor uses pay-per-event pricing.

Charge event

You are charged for each completed plagiarism analysis that is saved as a report. Input checks, failed public-source access, and runs stopped before a report is saved are not charged as completed checks. Apify platform usage may still apply.

🔌 Integrations

Use the Apify API, schedules, webhooks, dataset exports, and Apify integrations to add reports to your workflow.

❓ FAQ

What happens if public sources cannot be reached?

The Actor first retries the source checks. If it still cannot get enough source evidence, the run fails with a clear message and saves no report. You can start the run again. A run without a saved report is not charged as a completed check.

What happens if source access fails after some matches are found?

The Actor keeps valid evidence already obtained and labels the result as partial when a later source failure prevents a full report.

Can I check a scanned PDF?

No. PDF files must contain text. This Actor does not run OCR on images or scanned pages.

Can I compare text with my own files?

Yes. Add TXT, Markdown, HTML, PDF, or DOCX files to referenceDocuments. The report gives one similarity percent for each file.

Does a match prove plagiarism?

No. The report shows text overlap with found sources. Review the source, quotes, and citations before you decide what the match means.

Does it check every page on the web?

No. It checks publicly discoverable web and academic sources. It cannot promise every web page, private source, or paywalled database.

Is this an AI detector?

No. It does not guess whether AI or a person wrote the text.

Is this plagiarism checker free?

No. A completed report has a pay-per-event charge, and Apify platform usage may also apply. Runs that do not save a completed report are not charged as completed checks.

Can it replace Turnitin?

No. It is a separate plagiarism checker that checks publicly discoverable web and academic sources. It cannot promise the same coverage as Turnitin or another service.

How is this different from other plagiarism checker tools?

It saves structured match evidence in an Apify dataset. You can export the report or use it with the Apify API, schedules, and webhooks.

📝 Changelog

v0.0

• Initial release.

🆘 Support

For issues, questions, or feature requests, file a ticket and I'll fix or implement it in less than 24h 🫡

🔗 Related Actors

• Readability Analyzer: analyze the same text or document for reading difficulty and hard sentences.
• Webpage Text Extractor: turn a public web page into clean text before you check it.
• arXiv Papers Scraper: find public academic paper records and source links for source review.
• URL to BibTeX Converter: turn a matched paper or web page URL into a BibTeX citation.
• Plagiarism Checker: run a separate public-source plagiarism check when you want another report to compare.

Made with ❤️ by Maxime Dupré