Regime keys

main_tax.regime_key (AEAT's clave_regimen) declares the tax regime that applies to the operation. Most lines run under the general regime ("01") — that's the default if you don't set anything. The other codes appear in specific scenarios; this page is the canonical catalogue.

For the exemption_reason values referenced here, see Tax classification per line.

The catalogue

These are the values of the RegimeKey enum in the spec. Each is a two-character string. "03", "06" and "14" are in the enum but rejected on a line (see Keys that are not accepted); List tax types only offers the keys that are accepted.

Where it goes in the request

regime_key lives inside main_tax, not at the line root:

{
  "lines": [
    {
      "description": "...",
      "quantity": 1,
      "unit_price": 100,
      "main_tax": {
        "type": "IVA",
        "percentage": 21,
        "regime_key": "01"
      }
    }
  ]
}

High-signal cases

"02" — Exports of goods (non-EU)

Mandatory for exports and the operations assimilated to them. Pair it with exemption_reason: EXENTA_ART_21 (E2 — goods leaving the EU) or EXENTA_ART_22 (E3 — operations assimilated to exports, such as international transport). The rule works both ways: regime "02" needs one of those two reasons, and those two reasons cannot go under the general regime "01". Full payload example in International customers > Exports of goods.

"03" — REBU (used goods, art, antiques)

Not accepted: a line with regime_key: "03" is rejected with 422 REGIME_KEY_NOT_SUPPORTED. Under the used-goods regime the invoice must not show the tax separately (RD 1619/2012, art. 16.2.c), and a BeeL. invoice always does. See Keys that are not accepted.

"07" — Cash-basis IVA (criterio de caja)

If you've opted into the cash-basis regime (Art. 163 decies LIVA), every issued invoice carries regime_key: "07". The IVA accrues when payment is received, not when the invoice is issued. The invoice PDF carries the mention «Régimen especial del criterio de caja». A "07" line cannot carry reverse charge or a not-subject reason, and of the exemptions only EXENTA_ART_20 or OTRO.

"17" — OSS / IOSS

For B2C distance sales of goods or services to EU consumers above the 10,000 € annual threshold. The line keeps the destination country's IVA rate — regime_key: "17" widens the accepted rates beyond the Spanish menu, so 19 % (Germany) or 22 % (Italy) are valid here. Do not set percentage: 0, and do not add an exemption_reason: BeeL. classifies the line as N2 from the regime key alone, and any exemption reason would force the rate to 0 % and drop the destination IVA from the breakdown. You still settle it via Modelo 369. Full payload in International customers > B2C OSS.

"18" — Equivalence surcharge

Set on every line that carries equivalence_surcharge_rate. See Equivalence surcharge.

"19" — REAGYP / Canary Islands

Two unrelated cases share this code: REAGYP (the special regime for agriculture, livestock and fishing) and Art. 25 Ley 19/1994 for the Canary Islands Special Zone (Zona Especial Canaria). Pick "19" when either applies; if unsure, talk to your tax advisor.

Keys that are not accepted

A line with one of these keys is rejected with 422 REGIME_KEY_NOT_SUPPORTED when you create, edit or issue the invoice, and so is a default key set to one of them in the tax configuration:

• "03" (used goods, art, antiques): under this regime the invoice must not show the tax separately (RD 1619/2012, art. 16.2.c), and a BeeL. invoice always does.
• "06" (group of entities): AEAT requires a cost-based taxable base the invoice does not carry.
• "14" (VAT pending in public works certifications): AEAT requires an operation date after the issue date and a public-administration recipient.

A corrective invoice of an original that already carried one of these keys keeps it.

What AEAT requires with each key

Checked on IVA and IGIC lines when you create, edit or issue the invoice, before it is numbered:

Cross-field validations BeeL. applies

Related