What is a second brain app?

A second brain app is software for capturing and retrieving the information you would otherwise forget — articles, videos, highlights, notes, and ideas. Instead of trying to remember what you read, you save it to a trusted external system and let that system do the remembering. Two things define a good one: capture is instant, and retrieval works even when you’ve forgotten the title.

Go deeper

For the full landscape — how second brain apps work, note-first versus save-first tools, and how to build one from the bookmarks you already have — read the in-depth guide: what is a second brain app? On how AI changed the category, see what is an AI second brain?

How Marqly approaches it

Marqly is a save-first second brain built as an AI bookmark manager: one-click capture from the browser extension, automatic AI tagging and summaries, and semantic search that finds a save from a half-remembered description. On Pro you can ask AI about your saved content and get answers drawn from what you’ve saved.