// IMMO.QUICK · GATETAXEXECUTION · GATE 18 · USTG § 12 · § 15 · § 13A/B

The POS receipt is now the attestation point.

gateTaxExecution deterministically seals the VAT calculation at the point of sale and attests that four tax preconditions are met and the booking is irrevocable. Support for tax authorities and businesses, never a replacement for a regulator's own recognition as evidence.

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In one sentence: gateTaxExecution recomputes the expected VAT, seals it at the point of sale, and locks the write window, so a later correction would be forensically disprovable.

✓ RELEVANT IF...

You need to make VAT calculation at the point of sale irrevocably provable
You need to forensically prove input tax deduction and reverse-charge recognition

✕ NOT RELEVANT IF...

You expect a tax office to automatically recognise the result as evidence
No VAT-liable supply or service at the point of sale is involved

// The problem

Until now, POS booking was contestable, legally possible, forensically barely re-computable.

VAT becomes due at the point of sale, when the supply or service is rendered. The gate deterministically seals the VAT calculation at the POS, the POS transaction, not the bookkeeping entry, becomes the legally relevant attestation point.

// Architecture

Four sub-gates, at the point of sale.

The deterministic check of the tax mathematics itself leaves no room and no estimation.

SUB-GATE 1

VAT Calculation (§12 UStG)

Recomputes the expected VAT from the gross amount and VAT rate and compares it against the VAT reported by the POS. A discrepancy triggers a block.

vat_rate · vat_amount_expected · vat_amount_reported

SUB-GATE 2

Input Tax Deduction (§15 UStG)

Confirms that the input tax is deduction-eligible and seals the invoice hash. The linked invoice remains forensically bound to the receipt via its hash.

input_tax_eligible · invoice_hash

SUB-GATE 3

Seller Verification (§13a/b UStG)

Checks the seller's LEI and the place of supply. If the place of supply is unclear or lies abroad, the gate checks reverse-charge recognition.

seller_lei_verified · place_of_supply · reverse_charge_recognized

SUB-GATE 4

Ledger Irrevocability

Confirms that the POS transaction is irrevocably booked and the write window is locked. A later change would violate the seal.

pos_write_locked

// Test results

Six tested scenarios.

All values on this page are fictional test data and serve only to illustrate the gate logic.

Scenario	SG1	SG2	SG3	SG4	Verdict
Fully clean	PASS	PASS	PASS	PASS	TAX_SEALED
VAT rate mismatch	FAIL	not evaluated	not evaluated	not evaluated	BLOCK_TAX_VAT_RATE_INVALID
Input tax not eligible	PASS	FAIL	not evaluated	not evaluated	BLOCK_TAX_INPUT_TAX_INELIGIBLE
Place of supply ambiguous	PASS	PASS	FAIL	not evaluated	BLOCK_TAX_PLACE_OF_SUPPLY_AMBIGUOUS
Write window not locked	PASS	PASS	PASS	FAIL	BLOCK_TAX_LEDGER_NOT_LOCKED
Seller LEI missing	PASS	PASS	FAIL	not evaluated	NO_DECISION

Test result: TAX_SEALED in 540 ms. Gross amount EUR 119, VAT EUR 19 (19%), input tax deduction eligible, seller LEI verified, place of supply DE, ledger irrevocably booked.

// Clarification

What gateTaxExecution is not.

Not automatic recognition by a tax office. The gate delivers a cryptographic proof, not regulatory admission as evidence.
Not an independent point-of-sale or bookkeeping system. The gate seals the POS attestation, it does not replace an existing cash register system.

The POS receipt is now the attestation point.

Until now, POS booking was contestable, legally possible, forensically barely re-computable.

Four sub-gates, at the point of sale.

Six tested scenarios.

What gateTaxExecution is not.

For tax authorities and businesses that want to make VAT execution at the point of sale provable.