Self-hosted Docker API for technical e-invoice workflows. It generates, validates, inspects, and normalizes Factur-X/ZUGFeRD CII and XRechnung UBL documents without uploading invoice data to a hosted service.

Factur-X Engine is a technical document-processing component. A successful API call is not a tax, accounting, legal, or regulatory opinion. Your application remains responsible for supplier matching, duplicate detection, purchase-order matching, tax policy, payment approval, filing, and acceptance decisions.

Validation results only describe the rules and layers that actually ran. Check validation_completeness, layers_executed, and layers_skipped before using a result.

docker run -d -p 8000:8000 --name facturx-engine \
  facturxengine/facturx-engine:2.1.0

Open http://localhost:8000/docs for the runtime OpenAPI documentation.

/v1/extract is useful for inspection and troubleshooting. It may expose missing, coerced, or truncated values and must not be used as an automatic accounting import decision.

/v1/serialize returns HTTP 200 only when validation is complete and the document can be represented by schema version 2.0.0 without recovery or fallback values. A successful response deliberately routes the caller to its own remaining controls:

The former Factur-X Engine Intake evaluation ended on 24 August 2026. No new evaluation or commercial keys are issued. In the published image, the endpoint returns FEATURE_NOT_ENABLED without a previously issued, unexpired key. The published source remains MIT licensed and may be forked and adapted without any support or maintenance commitment from this repository.

{
  "success": true,
  "schema_version": "2.0.0",
  "execution_status": "complete",
  "mapping_status": "complete",
  "validation_status": "passed",
  "suggested_route": "continue_client_checks",
  "client_checks_required": [
    "supplier_master_match",
    "duplicate_invoice_check",
    "purchase_order_match",
    "tax_policy_check",
    "payment_approval"
  ]
}

Invalid, incomplete, or unsupported documents return HTTP 422 with stable diagnostics containing code, source, path, and message.

The generation metadata model includes VAT exemption reason text, document and line billing periods, purchase-order and preceding-invoice references, and an optional VAT total in a distinct tax-accounting currency:

{
  "tax_details": [{ "exemption_reason": "Reverse charge" }],
  "billing_period": { "start": "20260701", "end": "20260731" },
  "purchase_order_reference": "BC-1234",
  "preceding_invoices": [
    { "reference": "FA-2026-0042", "issue_date": "20260715" }
  ],
  "tax_accounting_currency_code": "GBP",
  "tax_accounting_currency_amount": "85.00"
}

The two tax-accounting currency fields must be provided together, and that currency must differ from currency_code.

Example:

curl -X POST "http://localhost:8000/v1/validate" \
  -F "file=@invoice.xml"

curl -X POST "http://localhost:8000/v1/extract" \
  -F "file=@invoice.pdf"

curl -X POST "http://localhost:8000/v1/serialize" \
  -F "file=@invoice.xml"

curl -X POST "http://localhost:8000/v1/xml" \
  -F "metadata=$(cat examples/simple_invoice.json)" \
  -o invoice.xml

The API is local by design, but deployment security remains the operator's responsibility. Put it behind an authenticated reverse proxy or private network; do not expose an unauthenticated container directly to the internet.

• API reference
• OpenAPI specification
• Strict serialization schema
• Security policy
• Changelog

All code published in this repository is licensed under the MIT License. The commercial evaluation has ended. There is no checkout, new key issuance, paid offer, SLA, custom support, security response commitment, or compliance commitment. Existing copies remain available as-is under MIT; see the discontinuation notice.