Deriving it once is easy.
Remembering it cold is not.
Drop a textbook PDF or paste a problem set. Cortest builds cards for theorems, formulas, and derivations — with math rendered properly. Spaced repetition holds them through exam week.
Free to start. No credit card. ~60 seconds to your first deck.
Undergrad STEM · Grad quals · GRE Subject · Competitive exams
You solved it Tuesday. You forgot it by Friday.
Derivations, proofs, and formulas don't stick from a single pass. Problem sets build procedural memory — they don't build recall. That gap is where grades leak.
Close the gap with spaced recall, not more rereads.
- — Redo the same Griffiths problems twice
- — Copy lecture notes, reread them the night before
- — Memorize formula sheets the morning of
- — PDF + notes → cards for theorems, formulas, definitions
- — LaTeX renders $\int$, $\nabla$, $\lim_{x\to 0}$ cleanly *
- — FSRS resurfaces the ones drifting before the exam
Where it fits your week.
Proofs + definitions
Real analysis, abstract algebra, topology. Cards for definitions on one side, clean statement of the theorem on the other.
Physics formulas
E&M, quantum, stat mech. Formula on the front, derivation sketch on the back. Math rendering means $\hbar$ and $\psi$ look right.
CS concepts
Data structures, algorithms, operating systems, networks. Time complexity, edge cases, trade-offs — drilled at spaced intervals.
Calc + linear algebra
Integral tricks, matrix decompositions, eigenvalue problems. Fast recall for qualifiers and the GRE Math subject test.
Focus Lock
Problem-set blocks or formula drills. Timer on, distractions cost you. Works for study partners too — public session links.
Weak-spot radar
Miss the same type of convergence test three times? Cortest pushes more of them. Your exam = your weak spots.
Locked in, ahead of schedule.
“Dropped my Griffiths QM chapter on separation of variables. Got 34 cards with the PDEs rendered right. Focus Lock + 90 minutes = done what used to take me an afternoon.”
Physics undergrad, R1 universityJunior year“Algorithms qual prep. Fed it CLRS chapters on graph algorithms. The "explain differently" button on any card is the best feature — reformulates a proof sketch as pseudocode when I'm stuck.”
CS grad studentPhD candidate
Pricing that doesn't punish.
Start free. Upgrade when you need more.
Free
$0forever- 3 decks
- 100 AI generations / mo
- Focus Lock unlimited
- Spaced repetition
- Most popular
Pro
$9/ monthor $79 / year- Unlimited decks
- Unlimited AI generation
- Focus Lock + analytics
- Full FSRS + Anki import
Scholar
$19/ monthor $149 / year- Everything in Pro
- Canonical exam decks
- Voice mode
- Shared decks
Questions we get a lot.
Does it handle LaTeX / math notation?
LaTeX rendering is shipping in an upcoming release (KaTeX on web, math-view on mobile). Today you'll see raw TeX syntax — still readable, and the AI generates it correctly so your cards are future-proof.
Can it parse handwritten notes?
Yes — image upload (PNG / JPG / WebP) runs through GPT-4o vision. Whiteboards, handwritten notes, textbook photos all work.
What about code snippets?
Cards support monospace formatting with JetBrains Mono. Code blocks render fine. Syntax highlighting is on the roadmap.
Is it good for problem-solving, not just facts?
Facts and mechanisms first — then use the app's Application mode (shipping Phase 3) for higher-order questions. For now, it's strongest on recall.
Does it work for GRE Subject tests?
Yes. Drop the practice tests, build a deck per topic. Mastery trend plus weak-spot radar are designed exactly for this kind of prep.
Ready to lock in before quals?
Join STEM students building clean decks from their actual textbooks and problem sets.
Get Started for Free →No credit card required. Upgrade when you need more power.