Compliance & Business Tier 1 Ready POST /v1/invoice-validator

Invoice Math & EU EN 16931 / Peppol Validator API — Verify Totals & VAT Rules

Audit extracted invoices for line-item math errors, VAT mismatches, and Peppol compliance. Validate extracted invoice JSON for line-item arithmetic, VAT rate compliance, reverse-charge rules, IBAN/VAT syntax, and EU EN 16931 / Peppol conformance.

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1. Interactive Sandbox & Sample JSON Output

200 OK · Ready

Editable Request JSON (`POST /v1/invoice-validator`)

Live 200 OK Response Envelope

{
  "ok": true,
  "data": {
    "valid": true,
    "verdict": "valid",
    "math_valid": true,
    "en16931_conformant": true,
    "computed_totals": {
      "subtotal_net": 100,
      "total_vat": 0,
      "total_gross": 100,
      "vat_breakdown": [
        {
          "vat_rate": 0,
          "taxable_net": 100,
          "vat_amount": 0,
          "gross_amount": 100
        }
      ]
    },
    "issues": []
  },
  "meta": {
    "request_id": "req_inv_01",
    "ms": 1
  }
}

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2. Quickstart Code Examples

Full TypeScript & Python SDK →

curl -X POST "https://api.tinplate.dev/v1/invoice-validator" \
  -H "Content-Type: application/json" \
  -H "X-RapidAPI-Key: YOUR_RAPIDAPI_KEY" \
  -d '{"invoice":{"invoice_number":"INV-2026-0412","issue_date":"2026-11-14","currency":"EUR","seller":{"name":"Acme GmbH","vat_number":"DE123456789","country_code":"DE"},"buyer":{"name":"Client BV","vat_number":"NL123456782B01","country_code":"NL"},"line_items":[{"description":"Cloud API Pro","quantity":2,"unit_price":50,"net_amount":100,"vat_rate":0,"vat_amount":0,"gross_amount":100}],"subtotal_net":100,"total_vat":0,"total_gross":100,"reverse_charge":true},"check_en16931":true}'

import { TinplateClient } from "@tinplate/sdk"; // npm install @tinplate/sdk

const tinplate = new TinplateClient({
  rapidApiKey: process.env.RAPIDAPI_KEY!,
});

const { data, meta } = await tinplate.call("/v1/invoice-validator", {
  "invoice": {
    "invoice_number": "INV-2026-0412",
    "issue_date": "2026-11-14",
    "currency": "EUR",
    "seller": {
      "name": "Acme GmbH",
      "vat_number": "DE123456789",
      "country_code": "DE"
    },
    "buyer": {
      "name": "Client BV",
      "vat_number": "NL123456782B01",
      "country_code": "NL"
    },
    "line_items": [
      {
        "description": "Cloud API Pro",
        "quantity": 2,
        "unit_price": 50,
        "net_amount": 100,
        "vat_rate": 0,
        "vat_amount": 0,
        "gross_amount": 100
      }
    ],
    "subtotal_net": 100,
    "total_vat": 0,
    "total_gross": 100,
    "reverse_charge": true
  },
  "check_en16931": true
});
console.log(`[${meta.ms} ms]`, data);

import requests

response = requests.post(
    "https://api.tinplate.dev/v1/invoice-validator",
    headers={
        "Content-Type": "application/json",
        "X-RapidAPI-Key": "YOUR_RAPIDAPI_KEY",
    },
    json={
  "invoice": {
    "invoice_number": "INV-2026-0412",
    "issue_date": "2026-11-14",
    "currency": "EUR",
    "seller": {
      "name": "Acme GmbH",
      "vat_number": "DE123456789",
      "country_code": "DE"
    },
    "buyer": {
      "name": "Client BV",
      "vat_number": "NL123456782B01",
      "country_code": "NL"
    },
    "line_items": [
      {
        "description": "Cloud API Pro",
        "quantity": 2,
        "unit_price": 50,
        "net_amount": 100,
        "vat_rate": 0,
        "vat_amount": 0,
        "gross_amount": 100
      }
    ],
    "subtotal_net": 100,
    "total_vat": 0,
    "total_gross": 100,
    "reverse_charge": true
  },
  "check_en16931": true
}
)
print(response.json())

const response = await fetch("https://api.tinplate.dev/v1/invoice-validator", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "X-RapidAPI-Key": "YOUR_RAPIDAPI_KEY",
  },
  body: JSON.stringify({
  "invoice": {
    "invoice_number": "INV-2026-0412",
    "issue_date": "2026-11-14",
    "currency": "EUR",
    "seller": {
      "name": "Acme GmbH",
      "vat_number": "DE123456789",
      "country_code": "DE"
    },
    "buyer": {
      "name": "Client BV",
      "vat_number": "NL123456782B01",
      "country_code": "NL"
    },
    "line_items": [
      {
        "description": "Cloud API Pro",
        "quantity": 2,
        "unit_price": 50,
        "net_amount": 100,
        "vat_rate": 0,
        "vat_amount": 0,
        "gross_amount": 100
      }
    ],
    "subtotal_net": 100,
    "total_vat": 0,
    "total_gross": 100,
    "reverse_charge": true
  },
  "check_en16931": true
}),
});
const result = await response.json();
console.log(result);

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "tinplate_invoice_validator",
    "arguments": {
      "invoice": {
        "invoice_number": "INV-2026-0412",
        "issue_date": "2026-11-14",
        "currency": "EUR",
        "seller": {
          "name": "Acme GmbH",
          "vat_number": "DE123456789",
          "country_code": "DE"
        },
        "buyer": {
          "name": "Client BV",
          "vat_number": "NL123456782B01",
          "country_code": "NL"
        },
        "line_items": [
          {
            "description": "Cloud API Pro",
            "quantity": 2,
            "unit_price": 50,
            "net_amount": 100,
            "vat_rate": 0,
            "vat_amount": 0,
            "gross_amount": 100
          }
        ],
        "subtotal_net": 100,
        "total_vat": 0,
        "total_gross": 100,
        "reverse_charge": true
      },
      "check_en16931": true
    }
  }
}

OpenAPI 3.0.3 Schema Contract

Request Parameters & Response Schema Reference

Request Body Parameters (`POST /v1/invoice-validator`)

Parameter	Type & Constraints	Description
`invoice`required	`object`	Field 'invoice'
`rounding_tolerance`optional	`number` min: 0, max: 1, default: 0.02	Allowed rounding difference per line or total in currency units (default 0.02).
`check_en16931`optional	`boolean` default: true	Verify mandatory EN 16931 / Peppol BIS Billing 3.0 fields (BT-1..BT-115).

Response `data` Object Fields (`200 OK`)

Field	Type	Description
`valid`	`boolean`	Field 'valid'
`verdict`	`"valid" \| "warnings_only" \| "invalid"`	Field 'verdict'
`math_valid`	`boolean`	Field 'math_valid'
`en16931_conformant`	`boolean`	Field 'en16931_conformant'
`computed_totals`	`object`	Field 'computed_totals'
`issues`	`object[]`	Field 'issues'

3. What Invoice & EU EN 16931 / Peppol Validator API Detects & Validates

Line-item arithmetic: quantity × unit_price - discount = net_amount (with configurable rounding tolerance)
Tax breakdown verification: sum of net amounts, per-rate VAT buckets, and net + VAT = gross total
EU EN 16931 & Peppol BIS Billing 3.0 mandatory fields (supplier/buyer VAT IDs, issue date, currency, tax exemption reason for 0% VAT)
Cross-border EU B2B reverse-charge validation

Honest Engineering Boundaries

4. Known Limitations & Test Verification

Release Version: v1.0.7 · Last Verified / Benchmarked: 14 November 2026 · Latency Note: Sub-millisecond figures measure in-Worker V8 compute time (typical client HTTPS network RTT to the nearest Cloudflare PoP is 15–65 ms) · See Full Portfolio Benchmarks & Corpora →

Validates structured JSON extracted from invoices (e.g. from an LLM or OCR pipeline); does not perform raw PDF/image OCR itself.
Tested v1.0.4 (14 November 2026).

5. Marketplace Plans & Payload Quotas

Plan	Monthly Price	Included Requests	Rate Limit	Max Request Payload	Best For
BASIC	$0.00 / month	500 / month (hard limit)	10 req / min	64 KB	Evaluation, local development & CI smoke tests
PRO	$9.99 / month	15,000 / month	60 req / min	128 KB	Solo developers & production apps
ULTRA	$29.99 / month	100,000 / month	300 req / min	256 KB	Growing SaaS & multi-agent pipelines
MEGA	$79.99 / month	500,000 / month	1,000 req / min	256 KB	High-volume enterprise workloads

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6. Frequently Asked Questions

Why validate invoices after LLM / Document AI extraction?

Vision LLMs and OCR models frequently misread a digit or hallucinate totals. Running deterministic math and EN 16931 checks catches extraction errors before ERP import.

Does it handle penny-rounding differences?

Yes, you can configure rounding tolerance (default ±0.02) to distinguish rounding conventions from real arithmetic errors.

Does it check supplier IBAN and EU VAT IDs?

Yes, it validates supplier and customer VAT IDs and payment IBANs automatically.

Zero Payload Logging

7. Data Handling, Privacy & Marketplace Proxy Disclosure

Stateless in-memory invoice verification. Zero financial data is logged or retained.

Worker Zero-Logging Guarantee: Cloudflare Workers Observability and invocation logging are disabled in configuration (observability.enabled = false, head_sampling_rate = 0, invocation_logs = false). Payloads are processed strictly in volatile V8 memory and never logged or stored by Tinplate.

Marketplace Proxies vs. Direct Bearer Key: Requests sent via RapidAPI or Zyla API Hub pass through those marketplaces' proxy infrastructure (subject to their respective privacy policies). Security-sensitive workloads requiring end-to-end zero-intermediary processing can connect directly to https://api.tinplate.dev using a Direct Bearer Key (Authorization: Bearer <API_KEY>). Read our full Privacy Notice and OpenAPI 3.0.3 JSON Schema.