Pricing
One credit is one Easy problem.
A Medium costs 2, a Hard costs 4. A harder problem is a longer conversation. Spend your credits on whatever mix you want.
Build a month
Add the problems you want. The bar is what they cost.
28 credits of 30 · 2 to spare
Starter covers this: 30 credits every month at $19/mo.
Monthly credits refresh with each payment and don’t carry over. Credit packs are $12 for 12 credits, kept in reserve until your monthly credits run out, and expire 90 days after purchase. The free trial’s 6 credits are reserve credits too. They never expire and stay with you when you subscribe. The trial draws from a fixed 9-problem starter set (the same problems for everyone, in the same order), and 6 credits covers about six of them. Paid plans draw from the full curated library and follow the topic you ask for.