🔗 Offline QR Code Generation

🌐 Step 1: Select Environment

📘 Demo portal url Environment: https://einvoiceportaluat.impact.gr/

🟢 Production portal url Environment: https://einvoice.impact.gr

📋 Step 2: Collect Invoice Data

Gather the following parameters from your invoice json:

Parameter	Required	JSON fields	Example Value
`issuerTin`	✅ Yes	`issuer.registeredName`with country code	`EL036712001`
`customerTin`	⚠️ optional	`counterParty.vat` (can be empty for B2C)	`EL110099934`
`CustomerName`	⚠️ optional	`CounterParty.RegisteredName` (can be empty for B2C)	`Demo Company`
`invoiceType`	✅ Yes	`invoiceTypeCode` IAPR code	`1.1`
`series`	✅ Yes	Fiscal `series` of the document	`ΤΔΑ`
`number`	✅ Yes	Fiscal `number` of the document	`000028375`
`dateIssued`	✅ Yes	`dateIssued` in `yyyyMMddHHmmss` format	`20250621101302`
`totalAmount`	✅ Yes	`summaries.totalGrossValue` (with VAT)	`124`
`totalNetAmount`	✅ Yes	`summaries.totalNetAmount` (without VAT)	`100`
`totalVatAmount`	✅ Yes	`summaries.totalVATAmount`	`24`
`internalId`	✅ Yes	Must match `distributionDetails.internalDocumentId`	`ΤΔΑ1.100002837520250621101302`
`signature`	✅ Yes	SHA1 hash (see Step 3)	`f08035d66842456df2411a1ca0e738ff10376e4a`

🔐 Step 3: Generate Signature

3.1 Create String Signature

Concatenate the following fields in this exact order with - separator ( ⚠️ Important** except APIKey which has NO separator):

{issuerTin}-{customerTin}-{series}-{number}-{dateIssued}-{totalAmount}-{internalId}{APIKey}

Example Final String::

EL036712001-EL110099934-ΤΔΑ-000028375-20250621101302-124-ΤΔΑ1.100002837520250621101302c0e4a18d-d3b4-40e6-92d0-ac96becb01c8

3.2 Convert to UTF-8 Byte Array
Byte Array (128 bytes):

[69, 76, 48, 51, 54, 55, 49, 50, 48, 48, 49, 45, 69, 76, 49, 49, 48, 48, 57, 57, 57, 51, 52, 45, 206, 164, 206, 148, 206, 145, 45, 48, 48, 48, 48, 50, 56, 51, 55, 53, 45, 50, 48, 50, 53, 48, 54, 50, 49, 49, ...]

Expected Output:

Total Bytes: 128
First 10 bytes: [69, 76, 48, 51, 54, 55, 49, 50, 48, 48]
Last 10 bytes: [57, 54, 98, 101, 99, 98, 48, 49, 99, 56]

3.3 SHA1 Hash Calculation
SHA1 Hash Bytes (20 bytes):
[240, 128, 53, 214, 104, 66, 69, 109, 242, 65, 26, 28, 160, 231, 56, 255, 16, 55, 110, 74]

Algorithm: SHA-1 Output length: 160 bits = 20 bytes = 40 hex characters

3.4 Final Hexadecimal String
Final Signature (Hexadecimal):f08035d66842456df2411a1ca0e738ff10376e4a
Length: 40 characters - Charset: [0-9a-f]

🔗 Step 4: Construct Offline QR Code URL

4.1 URL Template

{portalUrl}/TransmissionFailure?issuerTin={issuerTin}&customerTin={customerTin}&customerName={customerName}&invoiceType={invoiceType}&series={series}&number={number}&dateIssued={dateIssued}&totalAmount={totalAmount}&totalNetAmount={totalNetAmount}&totalVatAmount={totalVatAmount}&internalId={internalId}signature={signature}

4.2 Complete Example

Demo URL:

https://einvoiceportaluat.impact.gr/TransmissionFailure?IssuerTin=EL036712001&CustomerTin=EL110099934&CustomerName=Demo+Company&InvoiceType=1.1&Series=%CE%A4%CE%94%CE%91&Number=000028375&DateIssued=20250621101302&TotalAmount=124&TotalNetAmount=100&TotalVatAmount=24&InternalId=%CE%A4%CE%94%CE%911.100002837520250621101302&Signature=f08035d66842456df2411a1ca0e738ff10376e4a

✅ Validation Checklist

Before finalizing, verify:

All required parameters are present

issuerTin include country code prefix (e.g., EL)

dateIssued is in yyyyMMddHHmmss format (NOT ISO format)

internalId matches distributionDetails.internalDocumentId exactly

URL is properly encoded (special characters in customerName, series)

Correct portal URL used (demo vs production)

🚨 Common Errors

Error	Cause	Solution
Invalid signature	Wrong concatenation order	Verify string format: `{issuerTin}-{customerTin}-...-{internalId}{APIKey}` (no `-` before APIKey)
QR code not working	Wrong portal URL	Verify demo vs production environment
Date format error	Using ISO format in URL	Use `yyyyMMddHHmmss` format (e.g., `20231010162042`)
Missing parameters	Incomplete URL	Ensure all 12 parameters are present
Signature too long/short	Wrong encoding	SHA1 hex string must be exactly 40 characters

📌 Quick Reference

Signature Formula:

{issuerTin}-{customerTin}-{series}-{number}-{dateIssued}-{totalAmount}-{internalId}{APIKey}
                                                                                    ↑
                                                                              NO HYPHEN

💡

The offline QR code is officially supported only for the provider. While it is technically supported for ERP e-invoice or documents that do not update MyData, the legalization of offline documents applies exclusively to provider-issued documents.

💡

The current implementation applies only to the transmission of invoices via a provider and does not cover cases of transmission through an ERP system.

Offline QR Code Instructions

🔗 Offline QR Code Generation#

🌐 Step 1: Select Environment#

📋 Step 2: Collect Invoice Data#

🔐 Step 3: Generate Signature#

🔗 Step 4: Construct Offline QR Code URL#

✅ Validation Checklist#

🚨 Common Errors#

📌 Quick Reference#