Quarkle is an AI-powered editorial assistant designed for self-published authors. It provides instant feedback on writing through real-time suggestions and automated reviews. The tool focuses on developmental editing, covering aspects like plot structure, character development, and dialogue consistency. Founded in 2023 in Boston, Quarkle targets writers seeking affordable alternatives to human editors.

Key features include the Autonomous Review system, which deploys 16 specialized AI agents to analyze manuscripts. These agents examine elements such as pacing, thematic coherence, and factual accuracy. The platform builds a knowledge base from user input to maintain continuity across long documents. Custom Review Agents allow users to configure feedback for specific needs, like grammar focus or story flow.

Quarkle supports brainstorming via open-ended chat and real-time note-taking during writing sessions. It integrates multiple AI models, including GPT-5 and Grok 4, selectable in the Pro version. Exports work to formats like Markdown or Word. The free tier offers unlimited basic access, while Pro unlocks advanced capabilities.

Competitors include Sudowrite for fiction ideation and Grammarly for proofreading. Quarkle differs by emphasizing narrative depth over general copywriting. Its pricing structure features a low-cost Pro plan compared to Sudowrites higher tiers. Users report strong performance on character consistency but note occasional bugs in extended reviews.

The tool handles full-length books without word limits in chat and reviews. It ensures data privacy through encryption and retains user copyright. Recent updates added model selection and custom agents. For optimal use, writers should start with the free tier to test compatibility with their workflow.