I Built an AI Writing Tool That Works With Any Provider — Here's How

I was tired of paying for multiple AI subscriptions just to handle different writing tasks. So I built Lubb Writer — an open-source tool that gives you 13 different text enhancement modes through a single interface.

Home page: https://lubb-writer.adelpro.us.kg/

The Problem

Most AI writing tools are:

• Expensive ($20-50/month)

• Single-provider (you're locked in)

• Desktop-only or require copy-pasting

I wanted something that:

• Works with any AI provider

• Integrates into my browser

• Costs nothing if I already have API keys

• Can be self-hosted

The Solution

Lubb Writer — a full-stack project with:

lubb-writer/
├── api/           # Express + TypeScript REST API
├── extension/     # Plasmo framework (Chrome, Firefox, Edge)
└── docker-compose.yml

Key Technical Features

Multi-Provider Abstraction

// provider-adapter.ts (simplified)
interface AIProvider {
  enhance(text: string, mode: WritingMode): Promise<EnhancedText>;
}

class ProviderFactory {
  static create(provider: ProviderType): AIProvider {
    switch (provider) {
      case 'openai': return new OpenAIAdapter();
      case 'anthropic': return new ClaudeAdapter();
      case 'gemini': return new GeminiAdapter();
      case 'custom': return new CustomAdapter();
    }
  }
}

Each adapter handles:

• API authentication

• Request/response transformation

• Error handling

• Token counting

Browser Extension with Plasmo

Plasmo makes cross-browser extensions painless:

// popup.tsx
function Popup() {
  const [text, setText] = useState('');
  
  return (
    <div className="w-80 p-4">
      <textarea 
        value={text}
        onChange={(e) => setText(e.target.value)}
        placeholder="Enter text to enhance..."
      />
      <ModeSelector onSelect={handleMode} />
      <EnhanceButton onClick={() => enhance(text)} />
    </div>
  );
}

One-Command Deployment

# Deploy the API
git clone https://github.com/YOUR_USERNAME/lubb-writer.git
cd lubb-writer/api
cp .env.example .env
# Add your API keys
docker compose up -d

# Install the extension
# Chrome: Load from build/chrome directory
# Firefox: Load from build/firefox directory

13 Writing Modes

Mode	Use Case
rewrite	Paraphrase while keeping meaning
summarize	Condense text
humanize	Make AI text sound natural
grammar	Fix errors
formal	Professional tone
casual	Conversational tone
academic	Scholarly writing
SEO	Optimize for search
persuasive	Marketing copy
creative	Creative writing
Twitter	Character-limited posts
LinkedIn	Professional content
story	Narrative content

What I Learned

1. Provider abstraction is 60% of the work — each AI has different quirks

2. Keyboard shortcuts > click paths — Ctrl+Shift+Y is much faster than navigating menus

3. Docker is non-negotiable for easy self-hosting

4. Plasmo > vanilla extension APIs — cross-browser support without the headache

Try It

GitHub: https://github.com/adelpro/lubb-writer

Clone it, run it, break it, improve it. PRs welcome!

What's Next?

• [ ] Streaming responses for longer texts

• [ ] Team collaboration features

• [ ] API key management dashboard

• [ ] More writing modes

What features would you want to see? Drop a comment!