Generate GST-Compliant Invoices in Seconds — Never Miss a Filing Again

GST billing requires more than just putting a tax percentage on an invoice. You need the correct HSN/SAC code per product, the right tax calculation for intra-state vs inter-state transactions, proper invoice formatting meeting the Invoice Rules under CGST Act, and a data trail that feeds directly into your monthly GSTR-1 return. ASTech ERP's GST billing module handles every requirement automatically from the moment you create a customer invoice. GST billing in India has three distinct complexity layers: the calculation layer (getting the right rate on the right transaction), the compliance layer (e-invoices, e-way bills, filing GSTR-1 and GSTR-3B), and the reconciliation layer (matching your GSTR-2A with vendor invoices to claim the correct ITC). ASTech ERP addresses all three layers in a single integrated system, so you are not juggling billing software, a separate GST filing tool, and spreadsheets for reconciliation.

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How GST Billing Works in ASTech ERP

Every product in ASTech ERP is configured with its HSN code and applicable GST rate. When you create a sales invoice, the system determines the GST treatment automatically: if your GSTIN state code matches the buyer's, it applies CGST+SGST; if they are different states, it applies IGST. For services, SAC codes are used and the 18% standard service tax rate (or the applicable special rate) is applied. The resulting invoice shows each tax component separately on the face of the document as required by GST law. The invoice number follows a sequential series as mandated, and the invoice contains all mandatory fields — your GSTIN, buyer's GSTIN (for B2B), place of supply, invoice date, HSN code, and tax breakdown. You can email or WhatsApp the PDF invoice to your customer directly from the system.

From Invoice to GST Return in Clicks

The most tedious part of GST compliance for small businesses is not creating invoices — it is extracting and formatting data for GST return filing. ASTech ERP eliminates this entirely. All your sales invoices flow automatically into the GSTR-1 data, correctly categorised by document type (B2B invoice, B2C invoice, export invoice, credit note) and party-wise B2B summary. At month end, you go to the GST Reports section and download the GSTR-1 JSON file. Upload it to the GST portal — done. GSTR-3B is even simpler: the system calculates your output tax liability and eligible ITC from your purchase entries, giving you the figures to fill in your monthly GSTR-3B return. Businesses that used to spend 3 days per month on GST work typically get this down to under an hour with ASTech ERP.

E-Invoice and E-Way Bill Integration

India's e-invoicing mandate has been progressively extended to smaller businesses since 2020. If your annual turnover is above ₹5 crore, you are required to generate Invoice Reference Numbers (IRN) for every B2B invoice via the Invoice Registration Portal (IRP). ASTech ERP integrates with the IRP API — when you save a qualifying invoice, the system automatically sends the invoice data to the IRP, receives the IRN and signed QR code, and embeds both on the invoice PDF. You never need to log into the IRP portal separately. For goods consignments above ₹50,000, e-way bills are generated from the same invoice screen. The e-way bill number is recorded on the invoice and can be extended or cancelled directly from ASTech ERP if the shipment is delayed.

Frequently Asked Questions

Can ASTech ERP handle GST on both goods and services in the same invoice?+
Yes. A single invoice can contain line items for goods (with HSN codes and goods GST rates) and services (with SAC codes and service GST rates). The system calculates the correct tax on each line item and shows the consolidated tax in the invoice footer.
How does the system handle reverse charge mechanism (RCM) transactions?+
When you record a purchase from an unregistered vendor or from specific categories that attract RCM (legal services, GTA, import of services), you mark it as an RCM transaction. The system creates the RCM GST liability in your GSTR-3B and also records the eligible ITC in the same return period.
Does ASTech ERP support the composition scheme?+
Yes. If your business is registered under the Composition Scheme, you can configure this in settings. The system then creates bills of supply (no GST charged to customers), calculates your 1% or other applicable composition tax on sales, and generates the quarterly CMP-08 return data.
How do I handle GST rate changes mid-year?+
When the government changes a GST rate on a particular HSN code, you update the GST rate in the product master for that product. From that date, all new invoices use the new rate. Old invoices retain the rate that was applicable at the time they were created, maintaining a correct historical record.
Can I generate a GST invoice for advance payments received?+
Yes. ASTech ERP supports advance receipts for future supply. When an advance is received, a receipt voucher records it and the GST liability on the advance (since GST is payable on advances for services under certain conditions) is tracked. When the final invoice is raised, the advance is adjusted and the tax is settled correctly.

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