Validate Brazilian Nota Fiscal Eletrônica (NF-e, mod 55), NFC-e (mod 65), and CT-e (mod 57) XML against current SEFAZ schemas — and get back the exact element paths that failed, not a cryptic rejection code. Built for fiscal-tech developers, ERPs, and e-commerce checkout integrations that need to catch malformed fiscal documents before SEFAZ does.
Most Brazilian fiscal APIs (Focus NFe, Webmania, NFe.io) are full emission stacks — heavy, priced for issuers, and overkill if you already hold the XML and only need to validate it. This is a pure-data validator: POST the XML, get a structured pass/fail with typed errors. The schema rules and per-município NFS-e quirks are not replicated by generic global validators.
/NFe/infNFe/ide/nNF with typed codes (MISSING_REQUIRED, INVALID_FORMAT, CROSS_FIELD, UNSUPPORTED_VERSION, INVALID_ROOT).400 for malformed XML, 422 for schema-valid-but-content-invalid, 200 for valid./v1/ API, and daily SEFAZ schema-drift monitoring.{
"valid": true,
"errors": [],
"schema_version": "4.00",
"schema_kind": "nfe",
"municipality_specific_warnings": []
}
{"valid":true,"errors":[],"schema_version":"4.00","schema_kind":"nfe","municipality_specific_warnings":[]}
curl --location --request POST 'https://zylalabs.com/api/12732/nf-e+xml+validation+service+api/24631/validate+nf-e+xml' --header 'Authorization: Bearer YOUR_API_KEY'
--data-raw '
35
00000001
VENDA
55
1
1
2026-05-19T10:00:00-03:00
1
1
3550308
1
1
0
2
1
0
1
0
1.0
11222333000181
EMPRESA TESTE LTDA
RUA TESTE
100
CENTRO
3550308
SAO PAULO
SP
01000000
123456789012
3
22333444000172
CLIENTE TESTE LTDA
'
| Header | Description |
|---|---|
Authorization
|
[Required] Should be Bearer access_key. See "Your API Access Key" above when you are subscribed. |
No long-term commitment. Upgrade, downgrade, or cancel anytime. Free Trial includes up to 50 requests.
The API returns a JSON response that includes a validity flag, a list of per-element errors (with paths and error codes), the auto-detected schema version, the document kind, and any municipality-specific warnings.
Key fields in the response include "valid" (boolean), "errors" (array of error objects), "schema_version" (string), "schema_kind" (string), and "municipality_specific_warnings" (array).
The response is structured as a JSON object with top-level keys for validity, errors, schema version, schema kind, and municipality warnings, allowing easy access to each component.
The API provides validation results for NF-e, NFC-e, and CT-e XML documents, including error details, schema version, and municipality-specific warnings, ensuring comprehensive validation feedback.
Data accuracy is maintained through daily monitoring of SEFAZ schema updates, ensuring that the API uses the most current validation rules and structures for NF-e, NFC-e, and CT-e documents.
Typical use cases include validating supplier NF-e before ledger import in ERP systems, pre-validating CT-e/NF-e during e-commerce checkout, and ensuring compliance in document-intake pipelines.
Users can utilize the returned data by checking the "valid" flag to determine if the XML is valid, reviewing the "errors" array for specific issues, and addressing any municipality-specific warnings for compliance.
Standard data patterns include a "valid" flag of true for valid documents, an empty "errors" array, and specific error codes like MISSING_REQUIRED or INVALID_FORMAT for invalid documents, providing clear feedback on issues.
To obtain your API key, first sign in to your account and navigate to the API you want to use. From the API's Pricing section, choose a plan and complete the subscription process. Once subscribed, return to the API page and you will see your API Access Key displayed at the top of the documentation page. You can use this key to authenticate your requests.
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The free trial lasts for 7 days and allows you to make up to 50 API requests.
No, the free trial is available only once, so we recommend using it on the API that interests you the most. Most of our APIs offer a free trial, but some may not include this option.
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