What is the best knowledge base app for iPhone?

It depends on how you capture. If most of what you learn comes from videos, articles and PDFs, an app that saves them from the share sheet and makes them searchable, like BrainTube, needs the least upkeep.

Do I need to tag or file my notes?

No. BrainTube summarises each save and links related ones, and you find things by meaning rather than by folder.

Does it sync to my computer?

Your BrainTube account syncs with the web app at brain-tube.com, so what you save on iPhone is on your desktop too.

BrainTube is free with 30 credits a month plus credits you earn. Starter and Pro add more credits.

Guide · A knowledge base that fills itself

How to Build a Personal Knowledge Base on iPhone (2026)

Most note apps ask you to file and tag every note. Here is how to build a knowledge base on iPhone where saving takes one tap and finding things takes one question.

By Ilian Raykov, founder of BrainTube

The short answer

Share anything to BrainTube from the iPhone share sheet.
Each save is summarised and linked to related saves automatically.
Search by meaning, ask Cue, and let recall bring the important ideas back.

Step by step

1. Install BrainTube and sign in

Get BrainTube from the App Store and sign in. Your library is the same one you see on brain-tube.com.

2. Save from any app

Tap Share in YouTube, Safari, Files or Voice Memos and choose BrainTube. Videos, articles, PDFs, podcasts, screenshots and memos all go into one library.

3. Let it organise itself

Each save gets a summary and is linked to related saves, so there are no folders or tags to keep up.

4. Find and review

Search by what you remember, ask Cue a question across everything you saved, and review key ideas with FSRS spaced repetition.

Get started

Get BrainTube on the App Store.
Your library is also on brain-tube.com, and Claude, ChatGPT and Cursor can read it over MCP: setup guide.
Related: remember what you watch and read.

Frequently asked

What is the best knowledge base app for iPhone?: It depends on how you capture. If most of what you learn comes from videos, articles and PDFs, an app that saves them from the share sheet and makes them searchable, like BrainTube, needs the least upkeep.
Do I need to tag or file my notes?: No. BrainTube summarises each save and links related ones, and you find things by meaning rather than by folder.
Does it sync to my computer?: Your BrainTube account syncs with the web app at brain-tube.com, so what you save on iPhone is on your desktop too.
Is it free?: BrainTube is free with 30 credits a month plus credits you earn. Starter and Pro add more credits.

Save once. Query anywhere.

Your YouTube library, in the AI tools you already use.

Start free