Vinkius

NF-e Access Key Validator MCP. Stop processing bad fiscal data keys.

NF-e Access Key Validator checks Brazilian Electronic Invoice (NF-e) access keys for structural integrity and compliance. This MCP validates complex 44-digit tax keys, ensuring they pass mathematical checksums (Modulo 11) and adhere to current tax authority standards before your system uses them.

NF-e Access Key Validator MCP is compatible with Claude Claude
NF-e Access Key Validator MCP is compatible with ChatGPT ChatGPT
NF-e Access Key Validator MCP is compatible with Cursor Cursor
NF-e Access Key Validator MCP is compatible with Gemini Gemini
NF-e Access Key Validator MCP is compatible with Windsurf Windsurf
NF-e Access Key Validator MCP is compatible with VS Code VS Code
NF-e Access Key Validator MCP is compatible with JetBrains JetBrains
NF-e Access Key Validator MCP is compatible with Vercel Vercel
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Give Claude and any AI agent real-world access

Check Key Validity

Determines if a key's length and mathematical checksum are correct using the Modulo 11 algorithm.

Decompose Key Data

Splits a valid access key into its core components, such as CNPJ and State Code.

Audit Tax Compliance

Verifies that the extracted data fields follow current Brazilian tax authority regulations.

Waiting for input…

AI Agent
MCP Server

What AI agents can do with NF-e Access Key Validator MCP (3 Tools)

These three tools allow you to validate NF-e access keys by checking their mathematical structure, pulling out individual business data points, and auditing compliance with official tax authority standards.

Make your AI actually useful.

Add this MCP to Claude, Cursor, or Windsurf and your AI stops guessing. It gets real tools to look things up, take action, and handle the stuff you keep doing by hand.

Start using NF-e Access Key Validator MCP

Extract Key Metadata

Splits a working access key into its individual business parts like the CNPJ or State Code for inspection.

Validate Business Compliance

Checks if all components found in the key match current, allowed tax authority...

Verify Key Structure

Determines if an access key is valid by checking its length and running a...

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Pick your AI client below to get set up. Just create a Vinkius account, subscribe, and you're instantly up and running. We handle the entire backend infrastructure, delivering out-of-the-box support for HTTPS Streamable, SSE, and OAuth2—zero messy routing required.

NF-e Access Key Validator MCP is compatible with Claude

Claude AI

1

Open Claude Settings

Go to claude.ai, click your profile icon, then navigate to Customize → Connectors.

2

Add Custom Connector

Click the "+" button and select Add custom connector. Paste your Vinkius endpoint URL:

https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp

Replace [YOUR_TOKEN_HERE] with your token from cloud.vinkius.com. For OAuth-protected servers, expand Advanced settings to add credentials.

3

Start a conversation

Open a new chat. The NF-e Access Key Validator integration is available immediately — no restart needed.

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Start with NF-e Access Key Validator, then connect any of our 5,200+ other servers whenever your AI needs more. One click, no limits.

  • Use this MCP plus 5,200+ others, all in one place
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  • Works with Claude, ChatGPT, Cursor, and more
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The Constant Tax Headache

Every time a batch of invoices comes in from a partner, your team has to manually check the key format. You're copying and pasting these 44-digit strings into internal tools or spreadsheets, running validation checks that only catch half the problems—maybe the length is right, but the underlying CNPJ number might be outdated or non-compliant.

With this MCP, you pass the entire batch to your agent. The system runs a complete audit: first checking the mathematical integrity of the key, then decomposing it into usable parts like the State Code and CNPJ. You get back a clean list, separating what's ready for processing from what needs human tax review—all without leaving your workflow.

Access Key Validator MCP: Guaranteed Compliance

You eliminate the need to run multiple validation scripts. Instead of having one tool check the math, another check the CNPJ format, and a third checking compliance against current tax rules, this MCP handles all three in sequence.

The result is confidence. You don't just know if the key *looks* right; you know it passes every regulatory hurdle required by Brazilian law. It changes your process from reactive troubleshooting to proactive data ingestion.

What NF-e Access Key Validator MCP does for your AI

Dealing with Brazilian fiscal data means handling complicated keys that can't just be treated like normal strings of numbers. This MCP lets you validate those NF-e access keys, confirming they are both mathematically correct and legally compliant right out of the gate. You input a key, and it doesn't just tell you 'yes' or 'no.' It breaks down exactly what that key means—extracting crucial data points like the CNPJ number, state code, and document model.

Furthermore, it checks those components against official tax authority rules. If your system needs reliable fiscal data for invoicing, this is essential. You can connect to this MCP through Vinkius, accessing these specialized tools alongside thousands of others in one place.

Built · Hosted · Managed by Vinkius NF-e Access Key Validator - Validate Brazilian Tax Keys
Server ID 019ee7e4-2277-7213-9c5e-ff024edc5c50
Vinkius Inspector
Compliance Grade A+
Score 100/100
Vinkius Inspector Badge — Score 100/100

Frequently asked questions about NF-e Access Key Validator MCP

How does NF-e Access Key Validator check for structural validity? +

The MCP uses the verify_key_structure tool. This function checks both the required 44-digit length and runs a mathematical checksum using the Modulo 11 algorithm to ensure the key is mathematically sound.

What information can I get from extract_key_metadata? +

The extract_key_metadata tool breaks down the key into its core components. You'll receive distinct fields, including the CNPJ (company tax ID), State Code, Model number, and Series.

Does this MCP only check if the key is formatted correctly? +

No. It goes much further than format. While verify_key_structure checks the math, you also must use validate_business_compliance to ensure those components comply with actual tax authority rules.

Can NF-e Access Key Validator handle different types of invoices? +

It focuses specifically on Brazilian Electronic Invoice (NF-e) keys. The tools are designed around the required structure and compliance framework for that specific document type in Brazil.

Is this MCP faster than using a dedicated tax software tool? +

When integrated into an automated agent workflow, it is much faster. It lets you run validation checks against thousands of keys instantly without needing to switch between separate vendor platforms or manual interfaces.