CEI Format Validator

CEI registration: the legacy INSS number, now replaced by CAEPF and CNO

The CEI (Cadastro Específico do INSS) was a 12-digit registration, written NN.NNN.NNNNN/NN, issued to people and entities that had social-security obligations but no CNPJ — rural producers, individual employers, and especially construction works (obras). This tool checks that 12-digit format. The CEI was the key the old INSS used to collect contributions where a company registration didn't exist.

Since 2019 the CEI has been retired and split into two successors: the CAEPF (Cadastro de Atividade Econômica da Pessoa Física) for individuals with economic activity, and the CNO (Cadastro Nacional de Obras) for construction works. Old CEI numbers still appear on legacy documents and historical filings, so validating the format remains useful.

Who used a CEI

• Construction works: each obra got its own CEI to track INSS on the payroll of the build → now the CNO.
• Rural producers (segurado especial) and individual employers without a CNPJ → now the CAEPF.
• Domestic employers: historically registered via CEI before eSocial Doméstico.

Where it still matters

• Historical filings: GFIP/SEFIP records and old GPS guides reference the CEI.
• Migration: mapping a legacy CEI to its CAEPF/CNO successor during data conversion.
• Audits: reconciling INSS contributions from the pre-2019 period.
• Mock data / testing: validating the NN.NNN.NNNNN/NN mask in legacy importers.

Common pitfalls

• CEI is deprecated: don't issue new ones — use CAEPF (people) or CNO (works).
• CEI ≠ CNPJ: it was precisely for those without a CNPJ; don't validate it with CNPJ rules.
• Punctuation is cosmetic: normalise dots and slash before comparing.
• Format ≠ active: a well-formed CEI from a closed obra is historical, not current.

FAQ

Is the CEI still issued? No — it was replaced in 2019 by CAEPF (for individuals) and CNO (for construction works).

What replaced the CEI for a construction site? The CNO (Cadastro Nacional de Obras).

Why validate an old CEI at all? Legacy documents, GFIP/SEFIP history and migration mapping still carry CEI numbers.