Instant and self-serve: no account, no email, nothing to fill in — one click mints your key. A test key (bk_test_) carries a 100-document monthly allowance and runs against the same extraction engine as live keys — it is for integration and evaluation, not production traffic.
The key itself appears on the next page — shown once. Only a hash of it is stored, so it cannot be recovered later; if you lose it, come back here and create a new one.