A library that answers
Thousands of nonfiction books — distilled, indexed, and cross-wired into one searchable brain. Type a real question. Get the shelf that answers it, in seconds.
Catalog slip · ask the stacks
The literal reader
BM25 keyword search across every passage of every book. If a book says it, this reader finds the exact place it's said.
The intuitive reader
Every passage is embedded into vector space, so "why do I sabotage my goals" finds chapters that never use those words.
The librarian
Both readers vote; reciprocal-rank fusion merges them into one ranked shelf. Precision when you quote, intuition when you wonder.
It has a wallet. Book402 speaks native HTTP 402 — the x402 protocol. An agent hits the API, gets a price, pays a cent in USDC on Base, and reads. No signup. No API keys. No subscription.
$ curl book402.com/search/hybrid?q=pricing+strategy HTTP/1.1 402 Payment Required { "accepts": { "scheme":"exact", "price":"$0.01", "network":"eip155:8453", "payTo":"0x6B19…0Aba" } } $ curl -H "X-PAYMENT: …signed-usdc…" \ book402.com/search/hybrid?q=pricing+strategy HTTP/1.1 200 OK ✓ paid · settled on Base { "data": [ "Confessions of the Pricing Man", "$100M Offers", "Priceless", … ] }
Settled in USDC on Base via the x402 protocol. A serious research session costs less than the coffee you'd read a book with. Humans welcome; agents expected. Explore the library as a 3-D galaxy while you're here.