Plagiarism API

Plagiarism Checker API

Q: What does the Plagiarism Checker API return?

It returns a plagiarism score, verdict, summary, matched sources, source similarity details, submitted-text match ranges, highlight ranges, word count, scan ID and remaining credits.

Q: How much does a plagiarism scan cost?

A completed plagiarism scan costs a flat 2 API credits, regardless of the accepted text length. Credits reserved for a failed scan are refunded.

Q: What are the plagiarism API text limits?

The request must contain at least 50 characters and no more than 25,000 words. Word counting is script-aware, including CJK text.

Q: Can I safely retry a plagiarism request?

Yes. Send an Idempotency-Key header. Reusing the same key with the same content within five minutes returns the original response without another charge.

Q: How do I authenticate a plagiarism scan?

Send the API key in the X-API-Key header. The key must include the plagiarism_checker scope.

Scan submitted text for source overlap and return a plagiarism score, matched sources and exact highlight ranges in one structured response.

Create an API key ↗ Read the API reference ↗

2 credits per scan
Up to 25,000 words
Source ranges included

POST /api/plagiarism/scan/ 200 OK

SUBMITTED TEXT

Clear review policies help teams separate source overlap from properly cited material before drawing a conclusion.

0 96 192

Source trace

Connect every match to its source.

Each response includes the document score, source details and matching text ranges. Use them to show where the matched text appears, which source it matches and the similarity score.

SOURCE 01

Research policy handbook

example.edu

0.91 similarity

SOURCE 02

Editorial review guide

example.org

0.76 similarity

SOURCE 03

Published article

example.com

0.63 similarity

EXAMPLE RESPONSE EXCERPT

{
  "plagiarism_score": 0.18,
  "verdict": "moderate_plagiarism",
  "sources": [{
    "domain": "example.edu",
    "similarity_score": 0.91,
    "matched_word_count": 42,
    "matches": [{
      "submitted_range": {
        "start": 58,
        "end": 126
      },
      "similarity": 0.91
    }]
  }],
  "highlights": [{
    "start": 58,
    "end": 126,
    "severity": "high",
    "source_index": 0
  }]
}

Review ranges

Show where each source match appears.

Text offsets identify the exact passage in the submitted content. Each highlight also includes its severity and the source it matches.

Inspect the response schema ↗

EXCERPT 04 4 MATCHES

The review found that institutional policy works best when source overlap is considered alongside citation practice and drafting history. A match is a prompt to inspect the source, not a final judgment.

One request

Send text. Receive the score, sources and matches.

Send a JSON content string with a scoped API key. Requests must contain at least 50 characters and enough complete sentences for a scan, with a maximum of 25,000 words. A completed scan costs a flat 2 credits.

Open request parameters ↗

POST /api/plagiarism/scan/

curl -X POST \
  https://developer-portal.proofademic.ai/api/plagiarism/scan/ \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: review-482" \
  -d '{
    "content": "Text to check"
  }'

01 Authorize Use a scoped key

02 Submit Send the content

03 Trace Connect matches to sources

04 Review Show matches for review

Production details

Check limits and prevent duplicate charges.

Failed scans refund reserved credits. Send an idempotency key when retrying a request to avoid an accidental duplicate charge.

Input envelope

Text limits

Minimum: 50 characters and enough complete sentences
Maximum: 25,000 words
Counting: Script-aware, including CJK text

Review request rules ↗

Usage model

2 credits per scan

The completed scan has a flat cost, regardless of accepted text length. Failed scans are refunded.

1scan 2credits 5 minretry window 255key chars

Retry safety

Idempotent requests

Idempotency-Key: review-482

Same key, same text Original result, no second charge

Read error behavior ↗

Use cases

Use source matching in review workflows.

Education

Submission review

Attach matched passages and sources to a human-led academic review process.

Explore institutional workflows → Publishing

Editorial screening

Surface source overlap before an article, manuscript or contributor draft reaches publication.

Explore publisher workflows → Platforms

Originality features

Bring source URLs, ranges and severity into an existing review queue or content product.

View all solutions →

Developer resources

Find the request fields, response data and hosted checker.

Create your key in the platform, use the API reference during integration and explore the hosted plagiarism checker for a ready-made review experience.

Platform

Source and originality guides