Author Flow

Inspiration

The idea for AuthorFlow came from a very personal struggle. I had a brilliant idea for a book in my mind, but I couldn't write and publish it globally because I am not completely fluent in English. I realized there are millions of aspiring writers around the world who face the exact same barrier. They are incredibly expressive in their local/native languages but struggle to reach a global audience.

Furthermore, I noticed that most AI writing tools charge hefty monthly subscriptions that act as gatekeepers. I wanted to build a platform without barriers or high fees. The inspiration was simple: What if you could write in your own language, have AI translate it chapter-by-chapter into a global language, and do it all at cost-price by bringing your own API key?

What it does

AuthorFlow is an AI-powered book writing application designed to break down language and cost barriers for authors. Key features include:

• Write Local, Publish Global: Authors can write their drafts entirely in their native language. Our integrated AI instantly translates and professionally rewrites the content into a global language.
• Chapter-by-Chapter Control: Instead of bulk-translating and losing the essence, the AI processes the book one chapter at a time. This allows the author to read, verify, and manually edit the generated output to ensure the story perfectly matches their original vision.
• BYOK (Bring Your Own Key): To make book writing affordable, we introduced a BYOK feature. Authors can plug in their own LLM API key, allowing them to generate unlimited chapters at the raw API cost without paying any platform markups or hidden fees!
• Rich Text Editor: Built-in powerful formatting tools designed for long-form writing, keeping the focus entirely on creativity.
• Cloud Sync: Secure authentication and real-time syncing using Firebase so you never lose your progress.
• One-Click Publishing: Instantly export your finished manuscript into a beautifully formatted PDF ready for worldwide distribution.

How we built it

To accelerate our development and bring this massive vision to life, we built the complete application with the help of Antigravity, an advanced AI coding assistant. It helped us architect the codebase, write robust logic, and solve complex debugging issues rapidly.

For the frontend, we used Flutter, ensuring a smooth and responsive experience. For the backend, we utilized the Firebase Suite (Authentication, Firestore, and Cloud Functions). The core translation and rewriting logic is powered by an LLM integrated via Cloud Functions. To support the BYOK feature, we built a secure flow to encrypt and store the user's custom API key, passing it to our Cloud Functions dynamically. We integrated flutter_quill for the complex rich-text editing requirements. Finally, we used the Dart pdf and printing packages to generate the final book exports directly on the device.

Challenges we ran into

• Preserving the Author's Voice: Translating text can sometimes make it feel robotic. The biggest challenge was tuning the AI prompts so that it doesn't just literally translate, but actually captures the emotion and storytelling of the author's original native-language draft.
• Secure BYOK Implementation: Handling users' private API keys on the frontend and securely passing them to Firebase Cloud Functions for execution without exposing them required careful architecture.
• State Management & Rich Text: Handling complex document states within flutter_quill while dynamically swapping out native text for AI-generated text without causing UI stuttering was challenging.

Accomplishments that we're proud of

• Creating a tool that genuinely empowers non-English speakers to become globally published authors.
• Implementing a completely transparent, user-friendly BYOK (Bring Your Own Key) architecture that saves authors hundreds of dollars in subscription fees.
• Successfully integrating a production-ready Rich Text Editor with real-time AI translation and Firebase cloud saving.
• Leveraging advanced AI coding tools (Antigravity) to single-handedly build a full-stack, production-ready application within the hackathon timeframe.

What we learned

• Deepened our knowledge of Flutter's ecosystem, particularly regarding complex state management and on-device PDF generation.
• Learned how to effectively prompt engineer LLMs for creative writing and storytelling, rather than just standard factual translation.
• Learned best practices for securely handling and routing third-party API keys supplied by end-users.
• Mastered the workflow of pair-programming with an AI agent to drastically multiply productivity.

What's next for AuthorFlow

• More Language Support: Adding explicit support for a wider variety of regional languages to empower even more authors globally.
• Advanced Storyboarding: Adding visual corkboards for character and plot development.
• Direct Publishing Integrations: Connecting directly to Amazon KDP and other self-publishing platforms.
• Expanded Monetization: Rolling out optional premium tiers for users who prefer a managed AI experience instead of the BYOK route.

Built With

• antigravity