App spotlight

ECHO

A private, on-device “second brain” for your iPhone—capture ideas, connect notes, and surface what matters when you need it.

iOS · Apple Intelligence (on-device)

Second brain · Notes · Private AI

Karpathy-style second brain—on your device.

ECHO turns scattered thoughts into a searchable knowledge system. Capture notes fast, let on-device intelligence summarize and connect ideas, and build a personal memory you can rely on—without a cloud account.

What ECHO does

ECHO is a “second brain” app inspired by modern personal knowledge workflows: capture quickly, organize lightly, and rely on search + summaries to retrieve the right idea at the right time.

Core capabilities

  • Fast capture for ideas, meeting notes, study notes, and daily thoughts.
  • Search-first retrieval so you can find anything you’ve written.
  • AI summaries & highlights generated on-device to reduce rereading.
  • Connections between notes to surface related concepts and recurring themes.
  • Personal knowledge library that grows over time into your own reference system.

Why on-device matters

Your “second brain” is deeply personal. ECHO uses Apple Intelligence on-device so the intelligence can be helpful while keeping your notes private.

Designed for creators, students, and builders who want a private, durable memory system—on device.