Any recording, understood
Anything explained, turned
into a navigable library.
Chalk records your lecture, your meeting, or that hour-long tutorial and turns it into a clickable table of contents. Tap a topic and you jump straight to it. Clip just the part you need. And every note comes from what was actually said, nothing invented.
The Android beta is here
Everything also works right here in the browser. No account needed for the demo.
- 00:00Course logistics & today's roadmap
- 04:12Recap: limits and continuity
- 11:38The derivative, defined from scratch
- 23:05Rules of differentiation
- 35:50Worked example: optimization
- 48:20Q&A and exam pointers
Wherever someone’s explaining
Record anything. Understand everything.
If someone’s talking and you need to understand it later, it belongs in Chalk.
Live chapters
09:14Loss surfaces, learning rate
14:32Gradient descent, step size
Live captions
so Q3 spend shifts from acquisition to retention
From a pasted link
90 min → 12 chapters
Jump straight to the part you need
The 9am that moved too fast
Your professor is three slides ahead and you're still copying the last one. Hit record, put the pen down, and just listen. The chapters build themselves while the lecture happens, and the part you missed is waiting for you after class.
See it work
The real product, doing real work.
No mockups. These are the actual screens, replaying real flows.
Clean up a messy transcript
One click fixes stutters, punctuation, and obvious mishears. Not happy with a line? Run it again. The original always stays saved.
Remember it later
Watching it once isn’t studying.
Chalk builds a study pack from the recording itself, tuned to what this recording covered, not a generic review sheet.
Spaced-repetition flashcards
Grade a card and Chalk schedules the next one. Miss it and it comes back sooner.
A glossary anchored to the video
Every key term links to the second it was explained.
Quizzes that target what's easy to get wrong
Questions aimed at what people usually get wrong, not the easy recall.
Study pack
Calculus I · Lecture 12
Flashcard 3 of 18
What does the derivative measure at a point?
The instantaneous rate of change, the slope of the tangent line.
Key terms
Derivative
The rate at which a function changes at a single point.
For teachers
Record once. Hand your class a library they’ll actually use.
- No AV cart, no studio booking. Record from the browser and the class is live.
- Every lecture becomes a chaptered, searchable reference students can move through.
- Share one link. The chapters, notes, quizzes, and flashcards come with it, nothing to set up per student.
- See which chapters the class replays and which quiz questions they miss, all from that one link.
What we’re building next for departments and whole institutions:
Canvas & Moodle
Push a finished lecture straight into your LMS, so it lands where your students already are.
Whole-class rollups
Engagement and confusion across every lecture in a course, not just one at a time.
The gap
A recording isn’t the same as being able to find anything in it.
A screen recorder gives you a video. A notes app gives you a wall of text. Neither one lets you jump to the part you’re stuck on.
You scrub a three-hour recording to find five minutes, and re-watching it costs you the whole hour again. The knowledge was always there. A way to navigateit wasn’t.
The old way
Scrub & hope
Notes
Miss the nuance
Chalk
Tap to the moment
See it run
Drop in a recording. Get a clickable, searchable library in minutes.
Audio, transcript, AI chapters, and a clickable player, all built for you in a couple of minutes. No account, no setup.