India GST Compliance is where ERP discipline either begins or breaks.
GST Determination, Filing, and Remittance (India) looks operational from far away. In a real finance team, it is a chain of assertions: the right actor started the work, the required records existed, the control policy was applied, the state change was preserved, and the outcome can be explained later without rebuilding the transaction from emails and spreadsheets.
The expected business outcome is specific: GST filed and remitted monthly with reconciled ITC, zero manual HSN/SAC coding, and IRN compliance for mandated entities.
The control flow a finance team actually needs.
Step 1
HSN/SAC Code Mandatory On All Invoice...
Step 2
CGST/SGST/IGST Split Computed...
Step 3
E-Invoice Generation And IRN Stamping...
Step 4
GSTR-1 Data Transmitted To GSP Daily
Step 5
GSTR-2B Auto-Reconciliation Flags...
The ERP surface involved.
Module
India GST Compliance
Actors
Tax Manager, GST Suvidha Provider (GSP), GSTN Portal
Tier
Tier 2
Finance area
Tax & Regulatory Compliance
Region lens
US and UK finance teams
Publication date
April 16, 2026
HSN/SAC code mandatory on all invoice lines; CGST/SGST/IGST split computed automatically based on ship-from and ship-to states; e-invoice generation and IRN stamping via IRP for entities above the mandatory threshold; GSTR-1 data transmitted to GSP daily; GSTR-2B auto-reconciliation flags mismatches; GSTR-3B liability calculated from GSTR-1 minus GSTR-2B ITC; filing deadline alerts at D-5 and D-1.
US and UK teams have different compliance hooks, but the same control problem.
US teams usually care about clean evidence for audit support, vendor records, payment controls, tax reporting, and management review. UK teams usually care about VAT-ready records, approval evidence, digital-record discipline, and traceable postings. The country-specific details differ, but the operating pattern is the same: the ERP needs controlled records, explicit ownership, defensible state changes, and evidence that survives beyond the person who completed the task.
The control matrix.
| Control area | Requirement | Acceptance proof |
|---|---|---|
| Control 1 | HSN/SAC code mandatory on all invoice lines | Given a sales invoice with HSN/SAC code, ship-from state, and ship-to state |
| Control 2 | CGST/SGST/IGST split computed automatically based on ship-from and ship-to states | when the invoice is confirmed |
| Control 3 | e-invoice generation and IRN stamping via IRP for entities above the mandatory threshold | then CGST/SGST (intrastate) or IGST (interstate) is split and computed automatically, and if the entity is above the IRN threshold the e-invoice is generated with IRN stamp via IRP |
| Control 4 | GSTR-1 data transmitted to GSP daily | negative) when HSN/SAC code is absent on any invoice line then the invoice is rejected with RFC7807 problem+json error code TAX_HSN_REQUIRED before confirmation. |
| Control 5 | GSTR-2B auto-reconciliation flags mismatches | GST filed and remitted monthly with reconciled ITC, zero manual HSN/SAC coding, and IRN compliance for mandated entities. |
| Control 6 | GSTR-3B liability calculated from GSTR-1 minus GSTR-2B ITC | GST filed and remitted monthly with reconciled ITC, zero manual HSN/SAC coding, and IRN compliance for mandated entities. |
Audit evidence is a chain, not a folder.
| Evidence layer | What should be preserved |
|---|---|
| Business event | Each sales invoice includes CGST, SGST/UTGST (intrastate), or IGST (interstate) computed based on the place of supply rules, HSN/SAC code, and applicable GST rate from the GST rate schedule. Invoice data is pushed to the GST Suvidha Provider in real time for GSTR-1 (outward supplies). At month-end, the Tax Manager reconciles GSTR-2B (auto-populated input tax credit from suppliers) against purchase register and claims eligible ITC. GSTR-3B is prepared with net liability, reviewed, and filed on the GSTN portal. The net tax due is remitted via the Electronic Cash Ledger. |
| Control rules | HSN/SAC code mandatory on all invoice lines; CGST/SGST/IGST split computed automatically based on ship-from and ship-to states; e-invoice generation and IRN stamping via IRP for entities above the mandatory threshold; GSTR-1 data transmitted to GSP daily; GSTR-2B auto-reconciliation flags mismatches; GSTR-3B liability calculated from GSTR-1 minus GSTR-2B ITC; filing deadline alerts at D-5 and D-1. |
| Acceptance proof | Given a sales invoice with HSN/SAC code, ship-from state, and ship-to state; when the invoice is confirmed; then CGST/SGST (intrastate) or IGST (interstate) is split and computed automatically, and if the entity is above the IRN threshold the e-invoice is generated with IRN stamp via IRP; (negative) when HSN/SAC code is absent on any invoice line then the invoice is rejected with RFC7807 problem+json error code TAX_HSN_REQUIRED before confirmation. |
| Data record | |
| System event | |
| Lifecycle state | |
The useful version of this workflow is not only fast. It is inspectable. A controller, auditor, or operator should be able to move from source event to system record to state transition to final business outcome without guessing.
Implementation contracts.
Reference data model
`gst_invoice_line` { id: string, invoice_id: string, hsn_sac_code: string, supply_type: enum(INTRASTATE,INTERSTATE), cgst_minor: int64, sgst_minor: int64, igst_minor: int64, currency_code: char(3), irn: string, irn_stamped_at: timestamp, external_id: string }; `gstr1_record` { invoice_id, transmitted_at: timestamp, gstn_ack: string }; `gstr2b_reconciliation` { purchase_id, status: enum(MATCHED,MISMATCHED,MISSING) }; (reference, product may differ).API and events
`POST /v1/gst/invoices` { lines[{ hsn_sac_code, amount_minor, currency_code, supply_type }] } -> 201 { id, gst_lines[{ cgst_minor, sgst_minor, igst_minor, irn }] }; `POST /v1/gst/gstr1/transmit` { period } -> 202 { job_id }; `GET /v1/gst/gstr2b/reconciliation` { period }; emits `gst.invoice_created`, `gst.irn_stamped`, `gst.gstr1_transmitted` events; idempotent via `external_id`.State transitions
`DRAFT -> IRN_PENDING -> CONFIRMED`; terminal `CANCELLED`; guard: IRN stamp required for mandated entities before invoice is delivered to customer; HSN/SAC code must be present on all lines.Common implementation traps.
Treating the workflow as data entry
If the ERP only stores the final record, the team loses the decision trail that explains how the record became valid.
Hiding exception logic
Exceptions need owners, reason codes, and time stamps. A vague pending state is not a control.
Posting without recovery design
Retries, duplicate submissions, and partial failures must be explicit so the system does not create inconsistent records.
Skipping evidence design
A workflow that cannot produce evidence on demand will eventually push finance teams back into manual screenshots and spreadsheets.
Where Rivane fits.
Rivane is built for finance workflows where automation must stay tied to source documents, approvals, state transitions, ledger impact, reporting, and audit evidence. Use this guide as a checklist for evaluating whether an ERP workflow is merely digitized or actually controlled.
References and source basis.
These sources provide the standards, regulatory, or government context around the flow. They are included so the guide is useful to finance operators, auditors, and implementation teams, not only buyers reading software copy.