Spec coverage

Following the Bank of Thailand / Thai Bankers’ Association / KASIKORN BANK Thai QR Payment supplement layered on top of EMVCo Merchant-Presented-Mode QR Code Specification v1.1:

Root TLV tags

Tag	Field	Status	Notes
00	Payload Format Indicator	✓	always 01
01	Point of Initiation	✓	11 static / 12 dynamic, auto-flipped on amount presence
29	Merchant Account Info — PromptPay	✓	GUID …0111 (standard), …0114 (OTA); shared by TrueMoney Wallet QR
30	Merchant Account Info — BillPayment	✓	GUID …0112 (domestic), …012006 (cross-border)
31	Merchant Account Info — KShop	reserved	constant exported; no builder helper yet
52	Merchant Category Code	✓	4-digit ISO 18245
53	Transaction Currency	✓	always 764 (THB)
54	Transaction Amount	✓	up to 9,999,999,999.99 — 2 decimals — satang input also supported
55	Tip / Convenience Indicator	✓	01 prompt / 02 fixed / 03 percentage
56	Tip Fixed	✓	THB
57	Tip Percentage	✓	2 decimals
58	Country Code	✓	always TH
59	Merchant Name	✓	up to 25 chars (auto-truncated)
60	Merchant City	✓	up to 15 chars
61	Postal Code	✓	up to 10 chars
62	Additional Data Field Template	✓	all 9 sub-fields
63	CRC-16/CCITT-FALSE	✓	poly 0x1021, init 0xFFFF, no reflect, no XOR out
64	Merchant Information Language Template	not implemented	open issue if you need it
80	VAT TQRC (BoT tax-qualified extension)	✓	3 sub-fields — promotes a payment QR to an e-tax-receipt source
81	Personal message	✓	UTF-16BE-as-hex; carried by TrueMoney Wallet QR

PromptPay merchant template (under tag 29)

Sub-tag 00 carries one of two AIDs:

• A000000677010111 — standard PromptPay credit transfer
• A000000677010114 — PromptPay credit transfer with One-Time Authorization (OTA)

The OTA AID is auto-selected when .ota(code) is set on the builder. Scanners route the payload through the single-use flow.

Sub-tag	Field	Status
00	GUID — A000000677010111 or A000000677010114 (OTA)	✓
01	Mobile Number — 13 chars 0066xxxxxxxxxx	✓
02	National ID — 13 chars	✓
03	e-Wallet ID — 15 chars	✓
04	Bank Account — 3-digit bank code + account no, 1–43 chars	✓
05	OTA code — fixed 10 chars	✓

TrueMoney Wallet layout (also tag 29)

Shares the PromptPay AID (A000000677010111) but the e-wallet sub-tag 03 carries a 14-prefixed 15-char identifier (14 + 13-char zero-padded mobile). The literal 14 prefix is the sole disambiguator at parse time. The optional personal message rides on tag 81 as UTF-16BE-encoded hex.

BillPayment merchant template (under tag 30)

Sub-tag 00 carries one of two AIDs:

• A000000677010112 — domestic cross-bank bill payment
• A000000677012006 — cross-border bill payment (ASEAN PayNow / DuitNow / QRIS interop)

When the cross-border AID is set, the additional-data purposeOfTransaction (tag 62 sub-tag 08) carries an opaque 18-char triple — currencyCode (3) + localAmount (13) + countryCode (2). The builder treats it as a raw string; compose / parse at the call site.

Sub-tag	Field	Status
00	GUID — A000000677010112 or A000000677012006 (cross-border)	✓
01	Biller ID	✓
02	Reference 1	✓
03	Reference 2	✓

VAT TQRC template (under tag 80)

Bank of Thailand tax-qualified extension. Promotes the surrounding payment QR to an e-tax-receipt source. Sub-tag order on the wire is 00 → 01 → 02.

Sub-tag	Field	Notes
00	sellerTaxBranchId	exactly 4 chars
01	vatRate	1–5 chars (optional)
02	vatAmount	1–13 chars

Additional Data Field Template (under tag 62)

Sub-tag	Field	Builder method
01	Bill Number	additionalData({ billNumber })
02	Mobile Number	additionalData({ mobileNumber })
03	Store Label	additionalData({ storeLabel })
04	Loyalty Number	additionalData({ loyaltyNumber })
05	Reference Label	additionalData({ referenceLabel })
06	Customer Label	additionalData({ customerLabel })
07	Terminal Label	additionalData({ terminalLabel })
08	Purpose of Transaction	additionalData({ purposeOfTransaction })
09	Additional Consumer Data Request	additionalData({ consumerDataRequest })

QR Code spec (ISO/IEC 18004 Model 2)

Aspect	Status
Versions 1-40	✓ all
Error correction L / M / Q / H	✓ all
Encoding modes (numeric / alphanumeric / byte)	✓ all + auto-detect
Reed-Solomon over GF(2^8) with primitive 0x11D	✓
Mask patterns 0-7 + penalty scoring	✓
Format info (BCH 15,5)	✓
Version info (BCH 18,6) for v7+	✓
Alignment patterns per Annex E	✓ pinned via regression tests after v0.1.0 bug
Quiet zone	configurable (default 4 modules)

Non-EMVCo envelopes

These wire formats share no tag space with the payment QR — different envelopes, different CRC tags (or none). They live in @thai-qr-payment/payload alongside the main TLV machinery.

Slip Verify Mini-QR

Printed on bank transfer slips. Resolves a transaction via bank Open APIs after slip OCR. Same EMVCo TLV grammar, different root tags.

Tag	Field	Notes
00	Root template (nested)	carries sub-fields 00 API type, 01 sending bank, 02 transRef
51	Country code	always TH
91	CRC-16/CCITT-FALSE	same algorithm as tag 63; positioned at tag 91 here

A TrueMoney variant uses a different sub-field layout under tag 00 and emits a lowercase hex CRC. See Slip Verify for the builder / parser API.

Bank of Thailand 1D bill-payment barcode

Counter-payment barcode scanned at bank tellers and 7-Eleven cashier stations. Not EMVCo TLV — a |-prefixed, \r-delimited ASCII string with no CRC.

|<billerId>\r<ref1>\r<ref2>\r<amount>

• billerId — 15 chars (Tax ID + suffix), zero-padded on emit
• ref1 — mandatory customer / invoice reference
• ref2 — empty string when unused
• amount — integer satang, or literal 0 when the cashier keys it in

See BOT barcode for the builder / parser API.

Reference standards

• EMVCo QR Code Specification for Payment Systems — Merchant Presented Mode v1.1
• ISO/IEC 18004:2015 — Information technology — Automatic identification and data capture techniques — QR Code bar code symbology specification
• Bank of Thailand “Thai QR Payment” supplement (referenced via the KBank API portal — not publicly indexed)