Products and tax engine

Product registry

POST /v1/produtos registers the company's product with its code (SKU). Validation happens at registration, not on the invoice:

Refusal	Official table
ncm_inexistente, ncm_fora_de_vigencia	Current Siscomex nomenclature (Resolução Gecex nº 926/2026)
cest_inexistente, cest_incompativel_ncm	Convênio ICMS 142/18, CONFAZ consolidated text
gtin_invalido, gtin_digito_invalido, gtin_prefixo_invalido	GS1 rules for check digits and reserved prefixes

SEFAZ homologação may even authorize a nonexistent NCM; production rejects the invoice. That is why registration checks it first. Each table comes from an official source, with the date of the copy and the SHA-256 of the source file.

The GTIN is also looked up in the SEFAZ Cadastro Centralizado de GTIN (centralized GTIN registry), with the company's certificate: if SEFAZ knows the GTIN with a different NCM, registration is refused with gtin_ncm_divergente. What SEFAZ returned is stored in gtin_sefaz. A GTIN unknown to SEFAZ, or a lookup that is down, does not block registration.

The invoice keeps a copy of the product as it was at issuance: changing the product later does not change an issued invoice.

Tax profile and approval

The product's tax profile states its ICMS treatment (tributado, base_reduzida, isento, nao_tributado, imune, st_retida, st_substituto), its PIS/COFINS treatment (tributado, monofasico, aliquota_zero, outros) and its IBS/CBS CST and classification. The company's profile (PUT /v1/nfe/perfil-fiscal/{empresa_id}) states its PIS/COFINS regime, whether it is an IPI taxpayer and, under Simples Nacional, the month's credit rate (CSOSN 101). Nothing is calculated without a profile approved by a person from the company or the accounting firm: POST /v1/produtos/{codigo}/aprovacao-perfil and POST /v1/nfe/perfil-fiscal/{empresa_id}/aprovacao record who approved it and when. Changing a tax field clears the approval.

Sandbox with its own registry. The sdr_test_ key creates, changes and approves products and profiles in a separate registry of its own: nothing it stores appears to the production key, and it neither sees nor changes the production registry. This lets you test the whole calcular mode without touching what issues for real. The product's ambiente field says which registry it belongs to.

Wholesaler Termo de Acordo (Bahia)

For a wholesaler accredited under Decreto 7.799/2000, record the accreditation in the company profile (termo_acordo with number, item of the Anexo Único and validity period) and set termo_acordo: true on the products covered. The engine applies the 41.176% base reduction (CST 20) only where the decree applies: within the accreditation period, intrastate outbound to a taxpayer registered in Bahia or a non-taxpayer legal entity (art. 1º and §3º), sale or bonus, goods at the general rate (art. 5º), without ST (art. 4º), excluding toilet paper (art. 2º-A). Otherwise, the invoice goes out without the reduction and the reason comes in ajustes (termo_acordo_nao_aplicado). The period conditions (share of sales to taxpayers, revenue, transfers) belong to the accreditation: whoever approves the profile declares that they hold.

ICMS-ST

• Resale with ST previously withheld (CST 60 / CSOSN 500): the withheld-ST fields come from the purchase invoices Sudrel already captures, through the link between the product and the purchase item (POST /v1/produtos/{codigo}/vinculos-entrada, by GTIN, by supplier code or manually), from the latest acquisitions and proportional to the quantity going out (Convênio ICMS 142/18, cláusula décima quinta, §3º). Without a link, send st_retido on the item; with neither, the invoice goes out as you provide it, with a warning in ajustes.
• Substitute taxpayer on intrastate sales (st_substituto): ICMS10 (or ICMS70 with reduction), MVA from Anexo 1 of RICMS/BA and the intrastate rate. A sale to a final consumer has no subsequent operation and goes out as ICMS00. Anexo 1 items that require review, with FECP or with adjusted MVA are outside coverage.
• Interstate ST is outside coverage.

7% for ME/EPP (Bahia)

On an intrastate sale by a manufacturer to an ME or EPP opting for Simples Nacional and registered in Bahia, the rate is 7% and the benefit goes as an explicit discount on the invoice (Lei 7.014/96, art. 16, I, "c", and §1º): the engine calculates the discount, puts it in vDesc and explains it in infAdProd. The recipient's size comes from what you provide in destinatario.optante_simples; otherwise, from the CNPJ lookup, with the source in ajustes (nfe_destinatario_porte_consulta_cnpj). What you provide takes precedence.

PIS/COFINS and ICMS in the base

The company profile has exclui_icms_base_pis_cofins (default true, STF Tema 69): the PIS/COFINS base excludes the ICMS shown on the invoice and, on resale with ST, the withheld ICMS-ST. With false, ICMS stays in the base, which is the conservative choice for those not yet applying the exclusion.

Operations

operacao resolves CFOP, purpose and nature: venda, venda_consumidor_final, remessa (with subtipo: conserto, demonstracao, industrializacao or outras), transferencia, bonificacao and devolucao (with chave_referenciada and subtipo comercializacao or industrializacao).

What the engine calculates

Tax	Coverage
ICMS	Sudrel turns on the rule of the issuer's state when the company joins, in minutes and with no action from you. Bahia already comes with the full set, described here: intrastate operation, or interstate with a taxpayer recipient (12%, or 4% for imported goods). Simples Nacional: CSOSN 101 (with the month's credit), 102, 103, 300 and 500 (with ST withheld on purchases). Normal regime: CST 00, 20 (objective base reductions under BA law and the wholesaler Termo de Acordo), 40, 41, 60 (with ST withheld on purchases), 10 and 70 (substitute's ST on intrastate sales) and 7% for ME/EPP, with the BA FECP.
IPI	IPI taxpayer, own production, TIPI rate. Under Simples Nacional, not shown.
PIS/COFINS	Cumulative or non-cumulative regime, base without the ICMS shown (or with it, per the company profile) and without withheld ICMS-ST; zero rate. Under Simples Nacional, CST 49 not shown.
IBS/CBS	Normal regime, through the Receita Federal's official calculator.

Never a guessed value. Anything the engine does not resolve yet returns 422 fora_de_cobertura, with the fora_de_cobertura list (item, tax and reason), and the invoice can proceed in informado mode, which serves every state. If you need the calculation by Sudrel in that case, talk to support: the rule goes in within minutes. Examples: interstate ST, DIFAL, issuer in a state whose rule Sudrel is about to turn on, an intrastate sale by a manufacturer to a taxpayer whose size neither you nor the CNPJ lookup provided (Bahia has 7% for ME/EPP), PIS/COFINS on resale with ICMS-ST without the value withheld on purchases, and single-phase (monofásico) PIS/COFINS. If the official IBS/CBS calculator does not respond, fora_de_cobertura comes with temporario: true and retentavel: true: try again.

Conferir mode

The invoice goes out with YOUR values, and each difference comes back in ajustes with acao: "divergente" and the rule nfe_conferencia_divergencia. With recusar_divergencias: true in the company profile, an invoice with a difference is refused with 422 conferencia_divergente and the divergencias list.