Best AI App for Writing a Book in 2025–2026: A Practical Guide for Authors

In 2025–2026 authors have access to a growing set of AI assistants designed to support every phase of book creation. A 2025 roundup from TechRadar highlights tools such as Jasper for long‑form writing, Sudowrite for fiction craft, and Notion AI for organization and drafting, signaling a shift toward integrated stacks that blend idea generation, drafting, and revision with light human oversight. This article surveys the field, explains how to pick a stack, and offers a practical workflow you can adapt to fiction or non‑fiction.

Why do writers lean on AI in this period? The answer lies in speed, consistency, and the chance to test many narrative variations without rewriting from scratch. AI tools can summarize research, propose plot structures, draft chapters, and then let the author revise with a personal voice. When used responsibly, AI reduces drudgery while preserving human judgment for story, pacing, and emotional impact. However, accuracy matters, so you should verify factual content and cite sources when needed. Notion's team emphasizes privacy and control over inputs, while Sudowrite's fiction‑focused design helps maintain voice across scenes.

Notion AI: planning, drafting, and collaboration

Notion AI sits inside a familiar workspace, enabling authors to capture notes, build outlines, and draft chapters inside one app. Features include generating draft text guided by a style guide, analyzing uploaded PDFs and images, and turning scattered notes into a connected manuscript. The approach centers on context and collaboration, letting you anchor AI results to pages in your Notion workspace. In 2024 Notion introduced AI connectors and improved editing, and in 2025 updates the company refined pricing options for business customers.

For writers who juggle research, annotations, and drafts, Notion AI provides a single canvas to capture ideas, structure chapters, and keep track of sources. The ability to search across uploaded documents and reference materials means your outline can stay grounded in real data or cited ideas, while AI helps draft sections in a consistent voice. Notion also emphasizes data controls and workspace security, which matters when manuscripts include proprietary concepts or client material.

Sudowrite: a fiction‑forward drafting partner

Sudowrite positions itself as a writing partner tuned to narrative craft. It offers a Draft feature to generate substantial passages in your voice, a Rewrite tool to compare alternatives, and a Describe function for vivid imagery. It also includes Story Bible for worldbuilding, a plugin system to add specialized capabilities, and a library of prompts that adapt to many genres. The company emphasizes that Muse, its fiction‑oriented model, works with your style rather than imposing a generic voice. This makes Sudowrite a strong pick for novel‑at‑a‑time drafting and iterative polishing.

Plugins extend capabilities, enabling writers to test reader responses, simulate scenes with characters, or generate worldbuilding details on demand. The emphasis on voice preservation means you can push through drafts while keeping your narrative cadence intact. Sudowrite’s ongoing updates also expand the toolkit for setting, pacing, and descriptive narration, helping authors move from first draft to a finished manuscript with fewer bottlenecks.

Jasper: templates and long‑form workflow support

Jasper has built a suite geared toward long‑form writing, with templates, structured workflows, and “Boss Mode” style capabilities that help writers push through chapters and sections. A 2025 TechRadar roundup places Jasper among top picks for long‑form content creation, reflecting its emphasis on speed, outlines, and repeated drafting cycles for book‑length projects. Writers in fiction or non‑fiction may pair Jasper with Notion or Sudowrite to maintain consistency and voice across chapters.

Beyond draft generation, Jasper’s ecosystem includes templates tuned to various genres and audience needs, enabling a writer to shape tone, pacing, and structure from the first spark to the final chapter. While it can produce substantial text quickly, many authors couple it with a personal editing pass to ensure nuance, character depth, and scene economy align with their vision.

Grammarly and the evolving AI editing landscape

Editing remains a core part of any book workflow. Grammarly’s AI capabilities continue to evolve, and in 2025 the company rebranded into a broader productivity platform branded as Superhuman. The shift signals a wider trend where authors integrate writing, editing, and task management in a single ecosystem. For book projects, the implication is reliable grammar, style suggestions, and tone checks that can sit alongside drafting tools in a writer’s stack.

As editors and readers increasingly expect consistent voice and error‑free prose, alignment between the author’s intent and AI suggestions becomes essential. The newer agent‑based approach described in industry coverage points to AI assistants that can take on specialized tasks—such as checking for factual consistency, maintaining point‑of‑view consistency, or aligning with a given readership rubric—without replacing human judgment. Authors should still verify claims and maintain ownership of the final manuscript.

Workflows that pair tools for fiction and non‑fiction writing

A practical stack often blends Notion AI for planning and data organization, Sudowrite for craft and scene development, and Jasper or another long‑form engine for rapid drafting. For nonfiction projects, tools with strong citation features and live research integration become especially valuable; in addition, drafting in Notion or a dedicated writing app helps organize references, notes, and chapter progress. The ecosystem continues to expand, with new interfaces and plugins that ease testing of ideas, while keeping authors in their preferred voice. Academic and industry papers in 2025–2026 underscore the need for grounding AI outputs in verifiable sources and structured outlines, not generic text.

Beyond writing, the rise of multimodal capabilities lets authors incorporate visuals, world‑building documents, and character sheets directly into the drafting process. For example, research into prompt canvases shows that widget‑based prompts can reduce cognitive load and improve creative workflow, offering an appealing path for authors who want to see how ideas connect across chapters. This direction aligns with ongoing experiments in the field.

A snapshot of 2025–2026 tool profiles

A concise view of how these tools fit a book project, based on industry coverage and vendor materials, follows. The emphasis is on enabling a writer to move from concept to a complete manuscript with checks for tone, fact, and pacing.

Getting started: a practical 4‑step setup

• Define the book’s genre, audience, and your voice. Clarify the level of factual detail and the cadence you want to strike in each chapter.
• Choose a core stack: Notion AI for planning, Sudowrite for craft, and a long‑form engine (Jasper or similar) for drafting at scale. You can swap in alternates as you test what fits your process best.
• Create a style guide and a small set of prompts that reflect your authorial voice. Store these in Notion so the AI outputs stay aligned across chapters and scenes.
• Set a simple review process: a human pass after each major section, plus a final pass focused on pacing, character arcs, and clarity. Treat AI output as a draft companion, not a final authority on content.

Pricing and access considerations in 2025–2026

Pricing for AI writing tools varies by plan, usage, and whether an author operates solo or within a team. Notion AI pricing and access adjustments became a notable topic mid‑2025, with Notion outlining how AI access is structured across plans and the implications for teams. For solo authors, flexible monthly or yearly options remain common, while teams may see bundled features with higher security and admin controls. Always verify current pricing on official pages when you sign up.

As the ecosystem matures, many publishers and tech outlets stress careful budgeting: the value comes not just from drafting text but from how well an author can weave data, structure, and creative voice into a polished manuscript. The best approach is to pilot a compact stack, measure how quickly you move from draft to revision, and scale up only when you notice tangible gains in quality and consistency.

Future directions in AI‑assisted book creation

Researchers and product teams continue to push toward multimodal, context‑rich writing assistants that blend text with visuals, data, and worldbuilding documents. Early demonstrations point to canvas‑style interfaces and modular prompts that writers can arrange on a board, enabling rapid iteration and clearer organization of ideas. As models grow, tools may offer deeper support for argument structure, source verification, and genre‑specific craft conventions, all while preserving the author’s unique voice. These trends align with ongoing work in the field, suggesting a future where authors curate their own personalized AI workflows.

Quick-start checklist for your 2025–2026 stack

• Set a clear goal for the project: fiction, non‑fiction, or mixed genre; identify the core audience.
• Assemble a core AI stack: Notion AI for planning, Sudowrite for craft, and a long‑form drafting tool for chapters.
• Establish a style guide and prompts to keep voice consistent across chapters.
• Incorporate a human editing pass after key milestones to verify accuracy and polish.
• Iterate, measure progress, and adjust tools to optimize your workflow rather than chasing every new feature.

In sum, the 2025–2026 landscape offers a richer, more capable set of AI helpers for authors. When used with care, these tools can accelerate the writing process, improve structure, and help authors maintain a distinct voice from start to finish. The most effective approach blends planning and drafting tools with craft‑oriented assistants, all under a well‑defined editorial process. The result is a manuscript that reflects your intent and story without sacrificing the rigor readers expect.

• Sudowrite Sudowrite is a creative AI assistant designed for novelists who want to deepen scenes, flesh out ideas, and maintain pace across chapters. It offers brainstorming prompts, character generation, scene rewriting, and descriptive enhancement. With adjustable voice and tone settings, you can tailor passages to your book’s style, whether it leans toward dark, witty, or lyrical. The tool supports long-form writing with chunked editing, idea generation, and a world-building module to preserve continuity. It integrates smoothly with your workflow, provides quick rewrites to fix pacing, and helps overcome writer’s block while honoring your authorial voice.
  

• Jasper AI Jasper AI is a versatile writing assistant built for long-form projects like novels. It provides plot templates, character arc builders, chapter outlines, and scene prompts to spark momentum. The long-form editor maintains narrative cadence across sections, while tone and voice controls adapt passages to your chosen register. You can generate dialogue, description, and inner thoughts, then refine with rewriting modes that improve clarity and consistency. It also supports project folders, progress tracking, and collaboration options. Integrated research prompts help maintain accuracy while preserving your authorial voice. It offers multilingual support, enabling drafts in several languages for global audiences. This includes additional language support and ownership across markets.
  

• NovelAI NovelAI offers adaptive storytelling with a focus on immersive world-building and character development. It provides a creative environment with an evolving AI narrator that can generate scene options, dialogue, and descriptive passages guided by your prompts. The platform emphasizes consistent tone, atmosphere, and lore across chapters, helping you maintain continuity in complex plots. Built for writers who want privacy and comfort, NovelAI stores work locally or in secure cloud options and supports fine-grained control over prompts and generation length. It also enables iteration across chapters, saving and reshaping ideas to fit your evolving manuscript. Users manage settings to balance creativity with structure.
  

• Writesonic Writesonic is a versatile long-form writer that adapts to many genres and styles, including fiction drafting. It provides templates for outlines, scene blocks, and character sketches, plus an AI editor that rewrites passages for clarity and rhythm. The tool supports building chapters with auto-generated transitions, consistent voice, and scalable word counts, making it suitable for full manuscripts. It also offers collaboration features, version history, and acceptance of reference material to guarantee factual alignment in worldbuilding and settings. With multiple languages, Writesonic helps authors prepare drafts for international readers while preserving their unique style.
  

• ShortlyAI ShortlyAI focuses on rapid long-form writing with a clean interface that minimizes distractions. It streamlines flow by continuing writing from your last paragraph and suggesting directions for scenes, dialogue, and description. Features include an outline mode, a built-in editor for editing and tightening prose, and a focus on consistency across chapters. It supports keyword-based prompts, style adaptation, and batch export options to move drafts into your manuscript repository. Designed for solo writers, ShortlyAI helps maintain momentum and provides a straightforward environment for drafting full-length novels.
  

• Copy.ai Copy.ai is a flexible AI writing platform that supports long-form fiction and creative writing. It offers idea generation, scene prompts, and character sketches to fuel drafts, plus a powerful editor that refines tone, clarity, and pacing. The tool includes structured templates for acts and chapters, enabling consistent rhythm across scenes. It also provides collaboration options, research notes, and export formats suitable for manuscript prep. Copy.ai supports multiple languages and can adapt to various genres, helping authors form compelling openings, build tension, and sustain momentum from outline through to near-complete chapters.