Second Brain

Second Brain is a web-based AI knowledge base (with a Chrome extension) for productivity enthusiasts, creators, marketers, researchers, designers, and developers who want to capture and reuse everything they read, watch, and save.

Key capabilities include:

• Multi-format ingestion and understanding: paste links or upload content from TikToks, Instagram Reels, YouTube (shorts and long-form), LinkedIn posts, X threads, podcasts/audio, PDFs, articles, images/screenshots, and GitHub repos, with video processing that watches frames, transcribes audio, and reads on-screen text.
• Chat and semantic retrieval: chat with a single item or the entire library, combine sources in one query, and use semantic search to find ideas by meaning rather than keywords.
• Spatial workflows: an AI Visual Board (infinite canvas) for multi-threaded thinking with parallel chat nodes, sources, and notes visible together, plus auto-generated mind maps to reveal connections.
• Rich Pages for knowledge compounding: save AI outputs into Notion-like pages with headings, lists, images, and code blocks, and keep everything AI-searchable.

Pricing: Paid, with plans starting at $6/month (Basic $6/mo, Pro $20/mo, Ultimate $55/mo; credits-based).

Notable for supporting content types that many note apps and chat assistants do not fully ingest (especially short-form video and social posts), while keeping a persistent, searchable library instead of isolated chat sessions.