GST engine and GSP roadmap
From section 22 turnover exemptions to CGST, SGST and IGST splits, Deku prepares GSTR-1 and GSTR-3B as offline JSON for you to upload. Direct filing, e-invoices and e-way bills go through a GST Suvidha Provider; that connection is built, but none is connected yet.
Statutory thresholds
Below the turnover limit, a business doesn't have to register for GST. Deku lets it work in pure accounting mode, issuing bills of supply, without a GSTIN.
| Supplier | Annual turnover limit | Applies to |
|---|---|---|
| Service providers | ₹20 lakh | Professionals, consultants, designers, software and other service businesses in most states. |
| Goods suppliers | ₹40 lakh | Traders and manufacturers of goods in states that adopted the higher limit (Notification 10/2019-Central Tax). |
| Special category states | ₹10 lakh | Manipur, Mizoram, Nagaland and Tripura, under the proviso to section 22. |
General guidance only. The limit depends on what you supply and where, and Deku doesn't work out your own position; check it with your tax adviser.
Tax engine
When you sell within your own state, the tax is split in half: CGST to the centre and SGST to the state. When the buyer's place of supply is another state, the whole rate is charged as IGST. The total the buyer pays is the same either way.
Deku reads the state code from the place of supply and compares it with your company's registered state, so each line gets the right split. If an invoice's tax type and place of supply disagree, the returns flag it before anything is exported.
In pure accounting mode, the same sale is a bill of supply with no tax lines.
27 Maharashtra to 27 Maharashtra · Tax invoice, SAC 9983 at 18%
| Taxable value | ₹1,00,000 |
|---|---|
| CGST at 9% (central tax) | ₹9,000 |
| SGST at 9% (state tax) | ₹9,000 |
| Invoice total | ₹1,18,000 |
The customer's debtors account is debited ₹1,18,000.
The invoice register on the demo's sample books: every invoice carries its supply type.
Input tax credit
The GST you pay on purchases can usually be set off against the GST you collect on sales. That is input tax credit. Some credit is blocked by section 17(5) of the CGST Act, for example on food and beverages or on goods for personal use, and some is ineligible for other reasons, such as a late claim.
In Deku each purchase bill is marked eligible, blocked under 17(5) or ineligible. Blocked and ineligible credit needs a reason and is added to the cost of the purchase, and GSTR-3B reports each kind in its own table.
Nothing in Deku matches your credit against GSTR-2B yet; it comes from your purchase register, so check it against the portal before you file.
Purchase bill: ITC eligibility
Example: ₹1,00,000 same-state purchase, ₹18,000 GST
The tax goes to the input GST ledgers and is reported as eligible credit in GSTR-3B.
| Input CGST and SGST ledgers | ₹18,000 |
|---|---|
| GSTR-3B 4(A)(5), credit available | ₹18,000 |
| Reduces the tax you pay by | ₹18,000 |
GST Suvidha Provider
Deku doesn't file on the government portal with scrapers or shared passwords. Filing, e-invoices and e-way bills go through a GST Suvidha Provider. The connection is built into Deku, but no GSP is connected in this deployment and it hasn't yet been run against a real provider, so those buttons stay disabled and say why.
Built, not connected
Once the server is set up with a licensed GSP, you add your GST portal username in Settings and verify it with an OTP. Your portal password is never asked for.
Built, not connected
From an issued invoice, Deku sends the invoice to the GSP and keeps the IRN, acknowledgement number and signed QR code with it.
Built, not connected
Add the vehicle number, transporter ID and distance. The invoice details aren't typed again on another portal.
On an issued invoice
E-invoice and e-way bill
No GST Suvidha Provider is configured on this server.
This is what an issued invoice shows today: the buttons are there, disabled, with the reason beside them. Once a GSP is configured and your portal is connected, the same block shows the IRN, acknowledgement number, signed QR code and e-way bill number.
Your portal username and GSP session are stored encrypted with AES-256-GCM.
Offline JSON availableGSP not connected
Return exports
If you file on the GST portal yourself, Deku builds both returns from posted invoices and purchase bills for the month, in the portal's offline JSON format. You review them, download the JSON and upload it.
Outward supplies: invoices you issued
Monthly summary of tax and credit
1
Pick the month.
2
See anything that blocks the return, with a link to fix it.
3
Check the summary, and what the return doesn't cover yet.
4
Save the JSON and upload it on the GST portal.
Each return also lists what it doesn't cover yet, such as B2C large invoices, amendments, advances and reverse-charge inward supplies, so you know what to add on the portal.
Raise a sample GST invoice, record a purchase bill and find both in the returns, in the demo. No account or login needed.