Bring your own key
Paste an Anthropic, OpenAI, Google, or OpenRouter key. It stays in your browser and talks straight to the provider — there's no server of ours in between, and no subscription on top of what you already pay for tokens.
Bring your own modelThe tutor that
The tutor that
writes on the board
Upload your notes, slides, or lecture recording. Get a 1:1 lesson taught step by step on a live whiteboard — and interrupt it whenever you're lost. It runs on your own API key, so you pick the model and pay cents, not a subscription.
✓ No account✓ Nothing uploaded to a server✓ Live voice — it talks, you ask✓ Claude · GPT · Gemini · open models
Calculus II — lecture 9.pdfteaching
Ask anything
teach me integration by parts
Okay — integration by parts. It's just the product rule, run backwards.
wait, where did that 2 come from
Organic chemistryLinear algebraThermodynamicsMicroeconomicsCell biologyStatisticsUS historyDiscrete mathGeneticsCalculus IICircuit analysisMacroeconomicsOrganic chemistryLinear algebraThermodynamicsMicroeconomicsCell biologyStatisticsUS historyDiscrete mathGeneticsCalculus IICircuit analysisMacroeconomics
Three steps, then it teaches
Upload what you're actually studying
Lecture PDFs, slide decks, a Word doc, a photo of the notes you took in the margin, even a recording of the lecture. It gets read, split by page or slide or timestamp, and kept ready to cite.
Get taught, and interrupt
The tutor plans the lesson, then works it out on a live whiteboard — equations line by line, diagrams drawn edge by edge, plots sketched. Cut in whenever. It keeps its place.
Every other tutor app
marks up your tokens
They bundle one model into a monthly fee and eat the inference cost — which means they choose the cheapest model that survives a demo, and you pay whether you study or not.
Chalk asks for your key instead. Use a frontier model for a proof and a cheap one for flashcards. Watch the running cost in the corner. When you stop studying, you stop paying.
Paste a key, start teachingAnthropic
Claude Opus 5, Sonnet 5, Haiku 4.5
OpenAI
GPT-4.1, 4o, o4-mini
Gemini 2.5 Pro & Flash
OpenRouter
DeepSeek, Llama, Qwen, Mistral
Keys are held in your browser and sent only to the provider you chose. Uploaded material is parsed on your machine and stored in your browser's own database. Delete it any time from Settings — there's no copy anywhere else.
What studying with it feels like
“I uploaded four weeks of lecture slides the night before a midterm and it taught me the whole unit off my own deck. It cited slide numbers. I could check it.”
“The interrupt thing is what got me. I asked 'wait, where did that 2 come from' and it circled the exact line and re-derived it.”
“I already pay for an API key for work. Running my tutor on it costs about eleven cents an hour, which is roughly nothing.”
“It plots the function while it explains the function. My textbook doesn't do that.”
“Quiz generation from my own papers, then it walks me through the ones I missed on the board. That loop is the whole product.”
“Photographed my handwritten notes and it read them. Actually read them, badly-written arrows and all.”
“I uploaded four weeks of lecture slides the night before a midterm and it taught me the whole unit off my own deck. It cited slide numbers. I could check it.”
“The interrupt thing is what got me. I asked 'wait, where did that 2 come from' and it circled the exact line and re-derived it.”
“I already pay for an API key for work. Running my tutor on it costs about eleven cents an hour, which is roughly nothing.”
“It plots the function while it explains the function. My textbook doesn't do that.”
“Quiz generation from my own papers, then it walks me through the ones I missed on the board. That loop is the whole product.”
“Photographed my handwritten notes and it read them. Actually read them, badly-written arrows and all.”