Verify formal proofs with Lean
Compile the generated Lean code and check whether the formal proof passes verification.
What math are you working on?
Ask a mathematics question in your own words.
No account needed. Up to 3 free messages a day, including clarifications.
02 / The workspace
Tools for studying a proof.
Paid plans let you organize questions and formal proofs in projects.
Read the explanation with the code
Hover over a mapped Lean code line to highlight its corresponding explanation.
Keep related questions together
Paid plans let you save chats in projects to keep related questions in one place.
03 / Getting started
Start with a question.
Try PALS for free, then create an account for your workspace.
Paid plans differ in their utilization allowance and per-request maximum. Utilization tokens measure weighted AI input and output usage, not the number of questions. These planned allowances are provisional and may change before launch.
Guest
Free
3 messages per day
Questions and clarification replies share this daily limit. Guest chats are separate from your account history.
Try PALSFree account
Free
3 initial requests in total
Save your conversations. Creating projects requires a paid plan. The initial free allowance does not renew daily.
Sign upPlus
USD $10 / month
Provisional allowance: 1,000,000 utilization tokens per billing period
Provisional maximum: 100,000 utilization tokens per request
Create projects to organize related chats with a paid plan.
Check subscription availability in your account’s Billing settings.
Pro
USD $20 / month
Provisional allowance: 3,000,000 utilization tokens per billing period
Provisional maximum: 300,000 utilization tokens per request
Create projects to organize related chats with a paid plan.
Check subscription availability in your account’s Billing settings.
Research
USD $100 / month
Provisional allowance: 15,000,000 utilization tokens per billing period
Provisional maximum: 1,500,000 utilization tokens per request
Create projects to organize related chats with a paid plan.
Check subscription availability in your account’s Billing settings.
A few things to know.
Can I try PALS without an account?
Yes. You can send up to 3 free messages a day without logging in, including questions and clarification replies. Creating an account gives you a separate workspace with saved chats. Creating projects requires a paid plan.
Does every answer have a formally verified proof?
No. The guest experience provides AI-generated explanations and proof arguments. An ordinary answer is not a guarantee of Lean verification. AI answers can contain mistakes, so check the reasoning and assumptions.
Will my guest chat appear in my account?
Guest chats are separate from your saved account history and are not automatically transferred when you sign up or log in.
Can I purchase a paid plan now?
Monthly prices are Plus at USD $10, Pro at USD $20, and Research at USD $100. Check subscription availability in your account’s Billing settings.