Copyleaks AI Detector vs PlagiarismSearch

Copyleaks AI Detector identifies AI-written text, including writing that mixes AI and human passages. It supports more than 30 languages and names GPT-5, GPT-4, ChatGPT, Claude, Gemini, DeepSeek, Llama, Bloom, Rytr, and Jasper among the sources it detects. AI Logic explains flagged results, displays AI phrase frequency, and can identify text appearing in published content elsewhere. The web detector scans up to 25,000 characters without login; the website platform requires at least 255 characters and accepts up to 2,000 pages. A Chrome and Edge extension accepts 350 to 25,000 characters, and a Google Docs add-on and education LMS integrations connect it to other workflows. Personal costs $13.99 a year with annual billing or $16.99 a month; Pro costs $74.99 a year with annual billing or $99.99 a month. A free plan and free trial are listed. Copyleaks says data is encrypted at rest with AES-256, reports SOC 2 and SOC 3 certifications, and supports GDPR compliance.

PlagiarismSearch checks submitted writing against selected web, archived, publication, academic, and enabled organizational sources. Its reports identify matching or similar passages, link those passages to detected sources, and provide a similarity report. An AI writing feature gives probability indicators for the full text and individual passages, highlighting passages for review. The service also lists paper analysis, readability, and spelling and grammar tools. Users can check up to 150 words for free, while registered users can check up to 300 words daily at no charge. The maker says its academic database contains over 500 million indexed texts. Integrations include a Moodle plugin, Google Docs add-on, customizable API, and Viber and Telegram bots. The maker presents it for students, educators, writers, bloggers, universities, and organizations. Paid options include a Light one-time package at $9.95, paid once and monthly packages from $27.95 a month. The maker says uploaded documents are not stored, though reports may remain in an account until deleted by the user.