How It's Made

The technology, tools, and people behind SidePen.

Technology

SidePen is built on a modern stack chosen for speed, reliability, and a great writing experience.

Next.js

React framework powering the frontend and API layer.

React

Component-driven UI with server and client rendering.

Editor.js

Block-based editor providing a clean, distraction-free writing experience.

Supabase

Authentication, database, and real-time sync for documents.

Google Gemini

AI model powering inline suggestions, slash commands, and writing assistance.

Langfuse

LLM observability and prompt management for reliable AI features.

Tailwind CSS

Utility-first CSS for a fast, consistent design system.

Google Analytics

Usage analytics and insights to understand how writers use SidePen.

Google Fonts

Custom typography with Poppins and Geist Mono for a polished reading and writing experience.

Vercel

Hosting and deployment with edge performance.

Tools

SidePen was built with the help of these tools that made development faster and more enjoyable.

Claude Code

Anthropic's CLI for Claude. An AI-powered coding assistant used throughout development for writing features, debugging, refactoring, and maintaining code quality across the entire codebase.

Visual Studio Code

The primary code editor used for all development — lightweight, extensible, and integrated with Claude Code for an AI-assisted workflow.

Figma

Design and prototyping tool used for UI exploration, component design, and visual planning before implementation.

RT Plugins

A custom suite of Claude Code plugins built by Ryan Turner for streamlined development workflows — including blueprint-driven project planning, parallel subagent execution, and smoke testing.

Letter from Ryan

Hey there,

I'm Ryan Turner.

I built SidePen because writing with AI never really felt right to me. It always fell into one of two modes. Either I wrote something and asked the AI to polish it, or the AI dumped out a draft that I had to rewrite anyway. Lots of copy pasting, lots of context switching, and never a real sense of teamwork. Even tools like Notion, Obsidian, Google Docs, Claude, Gemini, and GPT felt clunky for actual writing.

So I decided to try something different. I hacked together a quick prototype of what I thought a good writing experience with AI should feel like. One day in, I was hooked.

That inspired me to make SidePen.

The goal is simple. AI should feel like a writing partner, not a separate tool you wrestle with. No jumping between apps. No pasting chunks of text around. Just writing, with AI right there, fully aware of the whole document.

Here's the basic idea:

The best part is that the AI understands the entire document, not just the paragraph you are working on.

That's it. SidePen is about staying in your flow and making writing with AI feel natural and genuinely collaborative.

Best,

Ryan