For students, professionals and the curious

Your notes, as a podcast.

Snap a page, drop a PDF or type any topic. castify ai turns it into a podcast with hosts who actually explain it, then lets you ask them anything.

Free to try right here, no download. Your first podcast is on us.

Download for iPhone See how it works

70,000+ learners

★★★★★4,000+ reviews

On your feed

castify keeps going viral.

20M+ views across TikTok and Instagram, and dozens more videos with 50K+.

@studyw.tok · 17.8M@juiceditup · 1.9M@professor_bill_goat · 500K+@ccx.study · 460K across 3 videos

Step 1 · Add anything

Whatever you're studying, drop it in.

Lecture slides, a chapter, a photo of the whiteboard, a link, or just a topic you're curious about. Try it right here.

Snap a page

Notes, textbooks, whiteboards

Files

PDFs, slides, docs

Paste text

Anything you've copied

Links

Articles and web pages

or type a topic and press go

🔎 Flip on Deep research and your host digs through the web for you

Step 2 · Pick your hosts

Learn from someone you actually like listening to.

Every host teaches their own way: memory tricks, stories, questions, or just plain clear. Tap one to hear them, pick your favorites, and make one with them.

Conversation · two hosts talk it through Teacher & student · one explains, one asks Solo · one voice, straight to it Quiz · test yourself as you go Debate · both sides of the argument

Step 3 · Press play

Study on the walk to class.

Turn the time you already have, the commute, the gym, the twenty minutes before bed, into time you're learning.

On the wayYour reading, done before you get there

On the busEyes free, mind on it

Before bedOne more pass before the exam

Step 4 · Ask your host

Lost for a second? Hit “Huh?”

Your host knows exactly where you are in the episode. One tap and they jump in to explain that moment, then pick up right where you left off.

What's that?The term you just heard, in plain words
SimplerThe same idea, explained like you're new to it
ExampleOne concrete example that makes it click
Go deeperThe next layer the episode skipped

Ancient China · Part 2

The P.S.W.I. Journey

Max
So remember the acronym PSWI. That's our timeline.
Dan
Okay, but wait. Pre-dynastic? What does that actually mean? Were there no rulers yet?
Max
Great question. Picture a wild garden before anyone plants in rows…

⇪ Share✨ Make it better

4:12-6:48

15151×

Tap Huh? on the phone, then pick one. Sound on.

Pharmacology4 parts · Max & Dan

✓

Part 1 · How drugs move through the body

Listened

✓

Part 2 · Receptors, agonists, antagonists

Listened

Part 3 · Beta blockers, explained simply

12 min left

Snap your next notes

Same hosts, same format, one tap

Collections

A whole course, one part at a time.

Episodes about the same class find each other. Add next week's notes and Part 4 picks up where Part 3 left off, with the same hosts.

Biology

Law

Chemistry

Economics

By the numbers

Loved in 50+ countries.

20M+views on TikTok & Instagram

70,000+downloads

★★★★★

4,000+App Store reviews

50+countries

70+languages castify episodes are made in

★★★★★This app is phenomenal! I use this app when I am sick of music on a drive and want to learn about something new.

Arne Rosenthal · App Store

I built castify for the version of me who missed a class at UMass and had to read three lectures of slides to catch up. Six hours of work for what should have been a one-hour lecture.

Upload your slides, get a podcast, listen on a walk. That's the whole idea. A year later a study creator showed it on TikTok and 17.8 million people watched.

I still read every review. Tell me what you'd make it better at.

Nate SullivanFounder, castify ai · nate@natesullivan.ai

Why it exists

Built by a student who missed class.

2023First version, built at night after a banking job

Dec 2024The TikTok: 17.8M views in a week

2025Full-time on castify

Today70,000+ downloads in 50+ countries

Questions

Good to know

What can I turn into a podcast?+

PDFs, slides, documents, photos of notes or textbook pages, pasted text, links to articles, or simply a topic you type in. Deep research mode can also gather sources on the web for you.

Is it free?+

You can try it for free, right here in your browser or in the iPhone app. Pro unlocks more episodes and extras like talking to your host. Prices are shown in the app.

Does it stick to my material?+

Episodes are built from what you add, so your hosts explain your notes, not a generic version of the topic.

Can I ask the hosts questions?+

Yes. Tap “Huh?” for a quick explanation of the moment you're on, or tap your host to talk it through out loud.

Is it only for students?+

Students use it most, from nursing to law school, but plenty of people use it to learn on the commute, prep for work, or dig into something they're curious about.