B2B GSTIN Detection & Verification

Capturing buyer GST numbers on standard Shopify plans can be challenging because checkout fields cannot be freely modified without Shopify Plus.

SuperGST solves this by inspecting order payloads across 5 fallback tiers in priority order:

• 1
  Tier 1 - Order Custom Metafield: custom.gstin
• 2
  Tier 2 - Customer Metafield: customer.metafields.custom.gstin or custom.buyerGstin
• 3
  Tier 3 - Note Attributes: Cart attributes populated by theme extensions or custom forms (normalized matching for gstin, buyergstin, gstnumber, gst, taxid, _gstin, and Company Name).
• 4
  Tier 4 - Order Notes: Explicit prefix matches (e.g., "GSTIN: 27AABCU9603R1ZX" or "TAX ID - 27AABCU9603R1ZX") and standalone 15-character valid GSTIN extraction.
• 5
  Tier 5 - Customer Notes: Static notes saved in the Shopify customer profile.

Shopify Native B2B Fallback:

If no GSTIN is found, SuperGST also checks native Shopify B2B company fields (company, company_location, billing company, and B2B order tags) to flag commercial orders.

Every extracted candidate is tested against the official GST Council algorithmic pattern:

^[0-9]{2}[A-Z]{5}[0-9]{4}[A-Z]{1}[1-9A-Z]{1}Z[0-9A-Z]{1}$

• Digits 1–2: 2-digit State Code (01 to 38, or 97).
• Digits 3–12: 10-character PAN of the business entity.
• Digit 13: Entity code representing the number of registrations under this PAN in the state (1–9 or A–Z).
• Digit 14: Default letter 'Z'.
• Digit 15: Algorithmic check code digit.

Sandbox & Government Testing Support:

For development and test environments, SuperGST also safely accommodates sandbox and government test registrations with alphanumeric check suffixes.

When a customer provides a valid GSTIN:

• The customer's legal business name and GSTIN are prominently displayed in the Bill To section.
• The document header is formally labeled TAX INVOICE (as mandated by Section 31 for B2B supplies).
• The invoice provides full CGST, SGST, and IGST breakdowns so the buyer can claim Input Tax Credit (ITC) seamlessly on the GST portal.