Grammar Checker API​

Combine with Copyleaks award-winning AI and Plagiarism Detector, for a full-spectrum suite dedicated to original, error-free writing. The Grammar Checker API was built with the developer in mind.

Actionable Data with the Grammar Score API

Give your users more than just a basic spell-check. Our API returns a comprehensive, easily parsable JSON response featuring the proprietary Grammar Score, which breaks down text into actionable Corrections, structural Insights, and Readability metrics.

True Multi-Language Intelligence

Break down global language barriers for your users. Unlike traditional tools that simply translate English grammar rules, the Copyleaks API provides native-level processing for Spanish, French, German, Italian, and Portuguese.

Comprehensive Detection for 30+ Writing Issues

The Copyleaks Grammar Checker API goes far beyond basic spell-check. Our robust engine detects over 30 distinct types of writing issues across grammar, mechanics, sentence structure, and word choice.

Seamless Processing for Any Document Format

Don’t let file formats limit your user experience. The Copyleaks Grammar Checker API processes raw text, HTML, academic formats like LaTeX, and Office documents (Word, PowerPoint, Excel).

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Built to Scale Across Industries

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Educational Institutions

Help students improve their writing skills and mechanics in real-time, without triggering false AI detection flags.

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Publishers & Media

Ensure user-generated content, articles, and drafts are error-free before publication while maintaining consistent quality across multiple writers.

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User-Generated Content Platforms

Maintain a high standard of communication and a clean online environment by integrating automated grammar checking into your forums or social platforms.

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Enterprise Content Governance

Empower your entire organization to communicate clearly and professionally, standardizing communication and saving hours of manual proofreading.

SDKs for Every Stack

Our officially supported SDKs help teams launch faster with clean, prebuilt code and example integrations. Each SDK is maintained, open source, and tested across use cases.

Grammar Checker For Educational Institutions

Copyleaks’ simple LMS integration empowers learning and error-free writing while keeping everything you need in one convenient place.

Powerful on its Own.
Unbeatable Together.

The Grammar Checker API is just the beginning. Combine it with our award-winning AI Detector, Plagiarism Checker, or Text Moderation features for a genuinely full-spectrum suite dedicated to creating original, error-free content the first time, every time

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Cloud-based Security and Compliance

Our top priority is always to keep your proprietary data and content secure. We do this by providing:

  • Cloud-based system architecture
  • 256-bit encryption with SSL connection
  • 100% HTTPS data transferring ensure your complete safety and security
  • FERPA Ready and no PII data retention
  • Plus, we are GDPR-compliant and SOC2 and SOC3 certified

To learn more, visit our Security and Compliance pages.

Ready to Build with the Copyleaks API?

Join thousands of developers and organizations securing content integrity with Copyleaks.

Frequently Asked Questions

No. A major concern for publishers and educational platforms is that writing assistants will trigger false positives in AI detection tools. The Copyleaks Grammar Checker API is specifically designed to provide structural, vocabulary, and mechanical corrections without triggering generative AI detectors. This empowers users to improve their writing with absolute confidence.

The API is highly flexible and built to handle a wide variety of formats without requiring developers to strip the text first. It seamlessly processes raw text, HTML content, academic formats like LaTeX, and Office documents (including Word, PowerPoint, and Excel).

Additionally, it supports analyzing PDFs through built-in OCR processing

Yes, the API offers true native-level support for multiple languages, making it a great fit for global platforms. Instead of simply translating English grammar rules, the API utilizes specialized native grammar engines for Spanish, French, German, Italian, and Portuguese. This ensures that suggestions and corrections sound completely natural to native speakers

The API provides a comprehensive JSON response that goes far beyond a basic spell-check. It returns a detailed Grammar Score broken down into three actionable categories: Corrections (tailored fixes for grammar, sentence structure, and word choice), Insights (data on average word/sentence length and reading time), and Readability (metrics on how easily the content can be digested, complete with historical data for progress tracking).