CNPJ

CNPJ (Cadastro Nacional da Pessoa Jurídica) is Brazil’s national registry identifier for legal entities, issued by the Receita Federal (Brazil’s federal revenue service). This crate’s Cnpj type is a validated, allocation-free representation of it.

use ftracker_identifiers::Cnpj;

let cnpj = Cnpj::parse("00.000.000/0001-91").unwrap();
assert!(cnpj.is_root());
assert_eq!(cnpj.as_str(), "00000000000191");
assert_eq!(cnpj.formatted().as_str(), "00.000.000/0001-91");

If you hold a Cnpj, it is guaranteed to satisfy every structural rule and the Módulo 11 checksum described in this chapter — there is no partially validated or “trust me” state.

In this chapter

• Structure & Formats — the three segments of a CNPJ, and the 2026 move to alphanumeric identifiers.
• Parsing & Validation — what Cnpj::parse accepts, and the rules every constructor enforces.
• Formatting & Display — rendering the compact and punctuated forms without allocating.
• Error Handling — the CnpjError variants and how to match on them.
• Feature Flags — optional serde, schemars, arbitrary, and proptest integrations.
• Examples — end-to-end usage, including sorting, deduplication, and use as a map/set key.

API reference

This book explains how and why to use Cnpj. For the full, generated API reference — every method signature, trait implementation, and doc-tested example — run:

cargo doc --open --all-features