Issue GST e-invoices and e-way bills for Shopify orders via GSP and Google

# Issue GST e-invoices (IRN) and e-way bills for Shopify orders Who it's for: Indian Shopify sellers who must issue e-invoices or e-way bills and still copy order data into the government portal by hand. Mistakes mean rejected invoices, wrong IGST/CGST splits and penalties. ## How it works 1. When an order is paid, it works out place of supply, the CGST/SGST or IGST split, HSN codes and a unique document number. 2. B2B orders get an e-invoice (IRN and QR code) through your GSP. B2C orders over ₹50,000 get an e-way bill. Everything else is logged as not required. 3. If the IRN already exists, it is fetched instead of duplicated. 4. A tax invoice PDF is rendered, archived to Drive and emailed to the customer, and the IRN is saved on the Shopify order. 5. A small form cancels an IRN within the 24-hour window. Failures post to Slack with the reason. ## Setup steps 1. Create a Shopify custom app (write_orders), add its token as Header Auth on Save IRN & Tag Order in Shopify, and replace REPLACE_STORE there. Connect the Shopify trigger. 2. Add your GSP login as Custom Auth: {"body":{"client_id":"…","client_secret":"…","username":"…","password":"…","gstin":"…"}}. 3. Fill in Seller & GST Config: GSTIN, address, state code, pincode, GSP URLs and transporter. Replace REPLACE-GSP and the GSTIN in the two cancel-lane GSP nodes too. 4. Create HSN Map (sku, hsn, gst_rate, uqc, is_service) and GST Register tabs. Connect Google Sheets, Drive, Gmail and Slack. 5. Run Gotenberg (docker run -p 3000:3000 gotenberg/gotenberg:8) where n8n can reach it. 6. Test with your GSP's sandbox and a paid test order. ## Customization tips The e-way bill threshold, shipping HSN and document prefix are in Seller & GST Config.