Finance · Module
Billing & Invoicing
GST invoices with e-invoice IRN, payment links and governed reminders from one flow
Billing & Invoicing turns won deals, subscriptions, rentals and timesheets into GST-compliant invoices with e-invoice IRN and payment links. A lite version is planned inside Year 1 (W2), growing to the full module in W3.
What it does
Billing & Invoicing is the first Finance module on the plan and the only one inside the Year-1 boundary, in a lite scope. It takes a billable event from elsewhere in One3 (a won deal or accepted quote in CRM, a subscription period, a closed agent-rental month, and from W3 approved timesheets or milestones) and produces a GST invoice, delivers it with a payment link, records the payment and, once Accounts arrives, posts it to the ledger.
Customers are a billing role on the shared party record, so the company you sold to in CRM is the company you bill. Items reference the shared product record with HSN or SAC codes. GST is computed per line as CGST and SGST or IGST by place of supply, with cess and rounding stored and totals checked against lines.
Statutory controls
Number series are gap-controlled per document type, financial year and prefix, and allocated inside the issue transaction. Issuing locks the invoice: corrections go only through credit notes, which need R4 approval. Where e-invoicing applies, the invoice is submitted to the IRP through one GSP adapter and the IRN, acknowledgement and signed QR are stored and printed on the PDF. A retry queue handles failures. IRN cancellation is allowed only inside the statutory window (verify window rules and e-way bill interaction).
Agencies and agent rentals
Two lines of business are planned in from day one. Agent-rental invoices show rent, usage credits, pass-through costs and an optional capped performance bonus (verify tax treatment). Agency tenants can rebill client sub-accounts at their own price list with agency branding.
Year-1 and later
In Year 1 there is no ledger. Sales, credit-note and payment registers and a GST summary by rate and place of supply export to CSV or XLSX for your CA. From W3 the module delegates tax determination to the Tax Engine, payment links and mandates to the Payments Hub, and posts to Accounts. GA features add usage-based lines from metering, proformas, debit notes, advance receipts, bill of supply and export invoices, multi-GSTIN billing, a customer portal, time and milestone billing, multi-currency invoicing, proration and coupons, and bulk invoicing runs.
Features
What Billing & Invoicing includes
Billing customers
Billing role on the shared party record with billing email, address, payment terms, default currency, credit limit field and status.
Tax profiles
Effective-dated GSTIN, registration type (regular, composition, unregistered, SEZ, export, overseas) and place-of-supply state, with GSTIN format checks.
Items with HSN/SAC
Invoice lines reference shared products with HSN or SAC, unit, default price and tax rate; free-text lines still need HSN/SAC where mandatory.
Invoice drafting from any source
Draft manually or from a won deal or quote, a subscription period or a rental contract, with line discounts, notes and attachments.
GST computation
CGST/SGST versus IGST by place of supply, cess and rounding, stored per line with totals verified against lines.
Gap-controlled numbering
Number series per document type, financial year and prefix (and per GSTIN in W3), allocated in the issue transaction.
Issue and immutability
Issue assigns the number, snapshots the bill-to, renders the PDF and locks the document; corrections only through credit notes.
E-invoice IRN via GSP
Submit to the IRP through one GSP adapter, store IRN, acknowledgement and signed QR, print the QR on the PDF, with a retry queue; sandbox first (verify).
Credit notes
Against an issued invoice with reasons, R4 approval, tax reversal and e-invoice reporting where applicable (verify).
Recurring subscriptions
Subscriptions with lines, monthly, quarterly or yearly interval, anchor day, trial, pause and cancel at period end.
Agent-rental and agency rebilling invoices
Rent, usage credits, pass-through costs and capped bonus lines, plus agency-branded invoices to client sub-accounts.
Payment links
UPI and card link per invoice via one gateway with expiry, shown on the PDF, email and WhatsApp; webhook payments allocated automatically.
Dunning policies
Steps by offset days, channel, template and autonomy level, with quiet hours, pause on dispute and a cap on messages per invoice.
Registers and exports for the CA
Sales, credit-note and payment registers and GST summary by rate and place of supply, exported to CSV or XLSX as the Year-1 ledger substitute.
Workflow
Billable event to paid invoice
- 1
A won deal, subscription period or rental month creates a draft.
- 2
Validation checks tax profile, HSN/SAC and address.
- 3
Approval rules route large invoices or discounts to the Approvals Inbox.
- 4
Issue locks the invoice and, where applicable, gets the IRN via the GSP.
- 5
The invoice goes out by email or WhatsApp with a payment link.
- 6
The gateway webhook records and allocates the payment.
Workflow
Correcting an issued invoice
- 1
A billing executive raises a credit note against the issued invoice with a reason.
- 2
A different person approves it as an R4 Action with step-up authentication.
- 3
Tax is reversed and the credit note is reported for e-invoice where applicable (verify).
AI
AI skills and Digital Employees
Reminder drafting
Personalised reminders per dunning step inside approved templates, with disclosure and amounts inserted from records.
HSN/SAC suggestion
Suggests codes for free-text lines and new items; a human confirms.
GSP error explanation
Explains e-invoice errors in plain language with the failing field and fix steps.
Pre-issue anomaly checks
Flags unusual amounts or discounts, possible duplicates of a deal or period, and customer GSTIN status risk.
Unallocated payment matching
Suggests which open invoices an unallocated payment belongs to; a human allocates.
Billing copilot
Summarises a customer's payment history, answers "why is this overdue?" and drafts follow-ups.
Digital Employees that use this module
- Collections Reminder Assistant
- Invoice & Payment-link Agent
They act through the same governed Actions as people; risky steps wait for approval.
Frequently asked questions
Is Billing & Invoicing part of Year 1?
Yes, in a lite scope planned for W2. The full module, with Tax Engine and Payments Hub delegation and ledger posting, is planned for W3.
Can I edit an invoice after issuing it?
No. Issued invoices are locked. Corrections go through credit notes, which need a separate approver.
Which GSP will generate IRNs?
One GSP adapter is planned, starting in sandbox and moving to production only after access and rules are verified.
How does my CA get the data without a ledger in Year 1?
Sales, credit-note and payment registers and a GST summary export to CSV or XLSX for your CA's accounting software.
See Billing & Invoicing in your workflow
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