Developers

Writing checks from your code

A REST API and an official MCP server on the same engine behind the Silvertext app. One request checks a draft for plagiarism, grammar, citations, and AI content, and returns the same structured report the app produces. Pay as you go, no subscription.

Create an API Key Read the Docs

const res = await fetch('https://api.silvertext.com/v1/checks', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer ' + process.env.SILVERTEXT_API_KEY,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    text: 'Your document text…',
    options: { plagiarism: true, grammarSpelling: true,
               citations: true, aiContent: true, style: true },
  }),
});
const { id } = await res.json();

Give Your Agent the Full Check

The MCP server plugs Silvertext into Claude, ChatGPT, Gemini, Cursor, and any MCP-compatible agent as callable tools: submit a draft, get plagiarism, grammar, citation, and AI-content scores, and read your credit balance.

MCP Server Setup

Build Checks into Your Product

Submit text or files and get back a structured report: plagiarism matches with sources, grammar fixes, citation issues, and an AI-content score. Choose a bare score or the full annotated document per request.

API reference

Gate Publishing Pipelines

Batch-check a content library or wire an originality gate into your CMS, Zapier or n8n flow. Pay as you go on credits that never expire, with no subscription to keep.

Pricing

Pay as you go, from $0.18 per 1,000 words

No subscription. Buy credits once, spend them on plagiarism, grammar, citation and AI-content checks in any combination, and keep them for as long as you like: credits never expire. You pay for the checks you turn on, so a plagiarism-only call costs less than one with everything on, and a check costs the same credits from the API, the MCP server and the app. Your first key comes with 1,500 free credits, so integrating costs nothing.

What runs on each document

Every checkalways40credits

Credits per started 250 words. A check that is off neither runs nor costs.

Words per document

Documents

Priced on

What it costs, plagiarism only

440 creditsper 1,000-word document, about $0.20

4 pages of 250 words × 110 credits a page (40 every check + 70 plagiarism).

Per 1,000 words: $0.20; on the 220k pack
One pack covers: 500 documents; 220,000 credits for $99

Request bodyRequest body for this selection

{
  "options": {
    "plagiarism": true,
    "grammarSpelling": false,
    "citations": false,
    "aiContent": false,
    "style": false
  }
}

Write every check out: a check left out of options runs, and is charged, by default.

Credit pack	Price	Per 1,000 wordsPer 1,000 words, plagiarism only	Per 1,000 words, everything on
1,500 creditsabout 3,250 wordswith your first key, about 3,250 words of plagiarism only	Free	Free	Free
10,000 creditsabout 22,500 wordsabout 22,500 words of plagiarism only	$4.99	$0.22	$0.30
20,000 creditsabout 45,250 wordsabout 45,250 words of plagiarism only	$9.99	$0.22	$0.30
50,000 creditsabout 113,500 wordsabout 113,500 words of plagiarism only	$24.99	$0.22	$0.30
220,000 creditsabout 500,000 wordsabout 500,000 words of plagiarism only	$99	$0.20	$0.27
1,000,000 creditsabout 2,272,500 wordsabout 2,272,500 words of plagiarism only	$399	$0.18	$0.24

Credits are metered per started 250 words, one page minimum, and never expire. Every check answers with what it cost.

Create an API key

Need more than a million credits a month? Talk to us.

Compared

What each plagiarism API returns

What a call gives back, from each vendor's own API documentation. Two of the five let you pay for what you use, without a subscription. Of the five, only Silvertext documents grammar, citation and plagiarism findings in the same report.

API	Pay as you go	Plagiarism	AI content	Grammar	Citations
SilvertextEvery check in one report. Credits never expire; the first key includes free credits.
Originality.aiAPI access comes with its Enterprise plan.⁴	¹	²	²	²	³
CopyleaksAPI access is priced by its sales team; the published plans are for the web app.¹⁰	⁵	⁶	⁷	⁸	⁹
Winston AIAPI credits are bought in its developer dashboard.¹⁴	¹¹	¹²	¹³	¹¹	¹¹
CopyscapeCredits bought in advance.	¹⁵	¹⁶	¹⁷	¹⁸	¹⁸

Every mark for another vendor is quoted from its own API documentation or pricing page, read on 23 September 2026; a dash means the feature is not in its published documentation. The numbers open each source, with a screenshot taken when we read it. Vendors change their APIs; check theirs before you decide.

Sources for this table

1.
Originality.ai, Pricing. No date shown on the page.
Read in full. Cited where a feature is not in the API documentation.
Open the pageScreenshotArchived copy
2.
Originality.ai, API documentation. No date shown on the page.
“Check for AI Detection, Plagiarism, Factual Claims, Readability, Grammar/Spelling and Content Optimization”
Open at the passageScreenshot
3.
Originality.ai, API documentation. No date shown on the page.
Read in full. Cited where a feature is not in the API documentation.
Open the pageScreenshot
4.
Originality.ai, Pricing. No date shown on the page.
“API access”
Open at the passageScreenshotArchived copy
5.
Copyleaks, Pricing. No date shown on the page.
Read in full. Cited where a feature is not in the API documentation.
Open the pageScreenshot
6.
Copyleaks, API docs: Submit File. No date shown on the page.
“Scan files to find where the content has been used elsewhere and check its originality.”
Open at the passageScreenshotArchived copy
7.
Copyleaks, API docs: Submit File. No date shown on the page.
“Detects whether the text was written by an AI.”
Open at the passageScreenshotArchived copy
8.
Copyleaks, API docs: Submit File. No date shown on the page.
“Enable automated Grammar Checker for grammar, spelling, etc.”
Open at the passageScreenshotArchived copy
9.
Copyleaks, API docs: Submit File. No date shown on the page.
Read in full. Cited where a feature is not in the API documentation.
Open the pageScreenshotArchived copy
10.
Copyleaks, Pricing. No date shown on the page.
“For education and enterprise solutions, including API access and LMS integration, please contact our sales team for a custom pricing plan.”
Open at the passageScreenshot
11.
Winston AI, API documentation: Introduction. No date shown on the page.
Read in full. Cited where a feature is not in the API documentation.
Open the pageScreenshotArchived copy
12.
Winston AI, API documentation: Introduction. No date shown on the page.
“Plagiarism detection: 2 credits per word”
Open at the passageScreenshotArchived copy
13.
Winston AI, API documentation: Introduction. No date shown on the page.
“AI content detection: 1 credit per word”
Open at the passageScreenshotArchived copy
14.
Winston AI, API documentation: Introduction. No date shown on the page.
“An account on our Winston AI developer dashboard is required to create your token for authorization.”
Open at the passageScreenshotArchived copy
15.
Copyscape, Frequently asked questions. No date shown on the page.
“Premium Credits can be purchased in advance by credit card or PayPal.”
Open at the passageScreenshotArchived copy
16.
Copyscape, Premium API guide. No date shown on the page.
“check new content (whether human or AI generated) for plagiarism as it enters your workflow”
Open at the passageScreenshotArchived copy
17.
Copyscape, Premium API guide. No date shown on the page.
“test whether content was generated by AI”
Open at the passageScreenshotArchived copy
18.
Copyscape, Premium API guide. No date shown on the page.
Read in full. Cited where a feature is not in the API documentation.
Open the pageScreenshotArchived copy