OCaml client for the public CEP API http://git.cep.is/ocaml/atom?h=v0.2.0 2026-07-27T23:42:18Z 2026-07-27T23:42:18Z Murilo Ijanc murilo@ijanc.org 2026-07-27T23:42:18Z urn:sha1:218bc8fbfbbdc2520130ef43652a6cd22a6e67fb A CEP that fails a lookup is rarely a random number. It is usually someone who knows the city and guessed the digits, and the classic guess is the -000 that 957 municipalities never received. The API now answers those 404s with a faixa naming the municipality whose band the number falls into, so a caller can ask "did you mean somewhere in Areal/RJ?" instead of returning a bare "not found". Cep_not_found becomes an inline record so the context rides along with the message, matching how Rate_limited and Server_error already carry theirs. It is still a 404: faixa is context on the failure and never promotes it to an address, and its bounds are the smallest and largest CEP that actually exist there — sparse across the interval, which is what the ceps count is for — not the bounds the Correios publish. Parsing is deliberately lenient. A missing, null, malformed or municipality-less faixa yields None rather than an error: a 404 is a clean answer, and no shape of this field should turn it into an Invalid_response. 2026-07-26T15:21:46Z Murilo Ijanc murilo@ijanc.org 2026-07-26T15:21:46Z urn:sha1:5598ea80735a51cb7b3690837b2b7d4240331b2d