Second Brain – AI Visual Board and Knowledge Base

TL;DR

TL;DR: Second Brain is an AI-powered visual knowledge base for creators that lets you drop in TikToks, YouTube videos, podcasts, and PDFs, then chat with your entire content library on a visual board. Plans start at $6/month.

Source and Accuracy Notes

⚠️ This section is MANDATORY. All links must be verified from actual source, not guessed.

• Project page: thesecondbrain.io
• HN launch thread: news.ycombinator.com/item?id=44107398
• License: Proprietary (no open-source repo found)
• Source last checked: 2026-07-18

What Is Second Brain?

Second Brain is a solo-founded tool that combines AI chat with a visual, interconnected knowledge system. Built by Dom, a solo founder, it solves the problem of AI chats disappearing without structure or memory.

The core idea: instead of a flat chat log, you get a visual board where content nodes (YouTube, TikTok, PDF, podcast) and AI chat nodes coexist and cross-reference each other. You can organize everything with Projects and Smart Tags, then ask the AI questions with full context.

Key features (from the HN launch):

• Save AI responses into editable docs (Notion-style Pages)
• AI Visual board with multiple content and chat nodes (Miro meets ChatGPT)
• Chat with YouTubes, TikToks, Audio, PDFs, GitHub repos, Looms, websites
• Organize using Projects and Smart Tags, then chat with full context
• Chrome extension for saving anything in 1 click
• Built on GPT-4.1, Claude Sonnet 4, Grok 3, and DeepSeek R1
• Privacy: user data is never stored on AI providers or used for training

Setup Workflow

Second Brain is a web app with a Chrome extension. No self-hosted option.

Step 1: Sign Up

Visit thesecondbrain.io and create an account. The Basic plan starts at $6/month.

Step 2: Connect Your Content

You can add content in several ways:

• URL paste: Drop a TikTok, YouTube video, podcast episode, LinkedIn post, PDF, or any URL directly onto the board
• Chrome extension: Click the extension icon to save any page to your current project in one click
• File upload: Drag and drop PDFs or other supported files

Step 3: Chat With Your Content

Once content is on the board, click the AI chat node and ask questions. Second Brain reads every frame of a video, every word of a podcast, and every slide of a carousel — things that ChatGPT typically skips.

Step 4: Organize With Projects and Tags

Group content into Projects and apply Smart Tags. When you start a new chat, the AI has full context of everything tagged, letting you query your entire content library semantically.

Practical Evaluation Checklist

• Content ingestion: TikTok, YouTube, Instagram Reels, LinkedIn, podcasts, PDFs, GitHub repos, websites
• AI models: GPT-4.1, Claude Sonnet 4, Grok 3, DeepSeek R1
• Organization: Projects, Smart Tags, visual board layout
• Chrome extension: Available for quick saves
• Pricing: Basic from $6/month; Pro unlocks visual boards and premium AI
• Privacy: Data not stored on AI providers or used for training

Security Notes

User data is not sent to AI providers for training. The tool uses AI APIs for inference only. As a proprietary SaaS product, there is no self-hosted option — data lives on Second Brain’s servers.

FAQ

Q: Is there a free plan? A: Basic plan starts at $6/month with 500 credits. A free trial or free tier was not clearly documented on the site.

Q: Does it work with long videos or podcasts? A: According to the launch post, Second Brain watches every frame and listens to every word, including for videos over an hour long.

Q: Is the source code open source? A: No. Second Brain is a proprietary closed-source product. No public GitHub repository exists.

Q: What AI models does it use? A: GPT-4.1, Claude Sonnet 4, Grok 3, and DeepSeek R1 — selectable by the user in chat settings.

Conclusion

Second Brain targets creators and social media managers who consume large amounts of video and audio content and want an AI assistant that can actually reason over it. The visual board approach is distinctive — it feels more like Miro than a traditional chatbot, which makes organizing and revisiting ideas more natural.

If you produce a lot of video and audio content and find yourself screenshotting or transcribing highlights manually, Second Brain automates that workflow. At $6/month for the Basic tier, it’s priced within reach of individual creators.

The proprietary model means no self-hosting, and the data storage question is worth evaluating for sensitive content. But for general creator use cases, it fills a real gap that generic AI chat tools leave open.