GST billing that's fast at the counter and right at month‑end.
Billing OS brings GST invoicing, barcode POS, inventory with batch & expiry, purchases and customer credit into one app — built for Indian retailers, pharmacies and distributors. Works without internet. One simple yearly price.
The daily headaches of running a shop — fixed
Notebooks, calculators and generic software cost you time at the counter and money at month-end. Here's what changes with Billing OS.
Long queues at the billing counter
Typing every item and calculating GST by hand during rush hour.
Scan, press F2, print
Barcode auto-add and keyboard shortcuts produce a GST bill in seconds.
Expired stock sold or thrown away
Batch numbers and expiry dates live in a register nobody checks.
Expiry alerts before it's too late
Every batch tracked with alerts for near-expiry and low stock.
Udhar you forget to collect
Customer credit scattered across a khata, WhatsApp and memory.
Digital khatabook with reminders
Credit limits, balances and one-click WhatsApp payment reminders.
Month-end GST chaos
Your CA chases bills; figures don't match; filing gets delayed.
GSTR-ready exports
HSN-wise, rate-wise sales with GSTR-1 and 3B exports for your consultant.
No idea of real profit
Sales feel good, but purchases, returns and write-offs never add up.
Daily sales & profit dashboard
See sales, margins, top items and slow movers every day.
Internet down = billing down
Cloud-only apps stall when the connection drops.
Offline-first by design
Runs on your computer with a local database. Optional cloud database.
Everything to bill, stock and grow — in one place
Every module included in every paid plan. No add-ons to buy later.
Fast POS billing
Keyboard-first counter billing built for rush hours.
- Barcode scan auto-adds items
- F1 search · F2 pay · F10 print · Esc clear
- Hold cart and resume later
GST invoicing
Compliant tax invoices with HSN, rate-wise CGST/SGST/IGST.
- B2B invoices with buyer GSTIN
- B2C retail bills
- Split tender: Cash, UPI QR, Card, Udhar
Printing & sharing
Silent printing on the printers shops already use.
- 2-inch & 3-inch thermal (ESC/POS)
- A4 / A5 invoice formats
- Share bill on WhatsApp
Inventory management
A live view of every item and its stock.
- SKU, barcode, HSN, MRP & tax per item
- CSV import of opening stock
- Low-stock alerts
Batch & expiry tracking
Essential for pharmacy and FMCG.
- Batch-wise stock
- Near-expiry alerts
- Damaged / expired write-offs with reasons
Purchases & vendors
Stock updates itself when you record a purchase.
- Purchase entry auto-updates stock
- Vendor ledger & payables
- Purchase returns
Udhar / Khatabook
Replace the paper khata for good.
- Credit limit per customer
- Running balance & repayments
- WhatsApp reminder links
Returns & write-offs
Accurate stock and profit, even when things go back.
- Sales returns restore stock
- Reason-coded adjustments
- Reflected in P&L
Reports & analytics
Know your numbers every day.
- Daily sales & net-profit dashboard
- GSTR-1 & GSTR-3B exports
- Item, category and customer reports
Multi-counter
Grow from one counter to many (Business plan).
- Multiple billing counters
- Shared stock across counters
- Local or cloud MySQL database
Backup & restore
Your data stays yours.
- One-click backup to file
- Restore without technical help
- Data stored on your machine
Secure licensing
Protected, hassle-free activation.
- Machine-bound encrypted license
- Grace period & in-app renewal
- Clock-tamper protection
See Billing OS on desktop and mobile
The screens your team will use every day.
Mobile view
One system for walk-in customers and business buyers
Bill retail customers at the counter and trade customers with full GST details — from the same stock and the same books.
Counter billing for consumers
Speed matters most when there's a queue.
- Barcode POS with keyboard shortcuts
- MRP-inclusive pricing and GST auto-split
- UPI QR, cash, card or split payment
- Thermal receipt or WhatsApp bill
- Udhar for regular customers with credit limits
- B2C sales summarised for GSTR-1
Kirana & supermarkets · Pharmacies · Garment & footwear · Electronics · Hardware
Tax invoices for business customers
Accuracy matters most when your buyer claims input credit.
- Buyer GSTIN, billing & shipping details on invoice
- Automatic CGST/SGST vs IGST by place of supply
- HSN-wise tax summary on A4/A5 invoices
- Customer credit and outstanding tracking
- Purchase entry & vendor ledger for your supply side
- B2B invoices exported for GSTR-1
FMCG distributors · Wholesalers · Stockists · Trade suppliers
Faster checkout
Barcode scanning and shortcuts mean fewer keystrokes per bill.
Less stock loss
Expiry and low-stock alerts reduce wastage and missed sales.
Better collections
Every rupee of udhar is visible, with reminders one click away.
Stress-free GST
Clean, consistent data your consultant can file from directly.
How Billing OS compares
Against the main types of billing tools Indian shops use today.
| Billing OS | Cloud / mobile billing apps | Desktop accounting suites | Notebook / Excel | |
|---|---|---|---|---|
| Bills when internet is down | ✓ Fully offline | Limited / varies | ✓ | ✓ |
| Keyboard + barcode counter POS | ✓ | Varies | Often add-on | ✕ |
| Batch & expiry alerts | ✓ All paid plans | Higher plans | ✓ | ✕ |
| Udhar with WhatsApp reminders | ✓ | ✓ | Manual | ✕ |
| GSTR-1 / 3B ready exports | ✓ | ✓ | ✓ | ✕ |
| 2"/3" thermal printing | ✓ Silent print | Via phone / Bluetooth | Needs setup | ✕ |
| Data stays on your computer | ✓ | ✕ Vendor cloud | ✓ | ✓ |
| Learning curve for counter staff | Low | Low | High | Low |
| Local installation & training | ✓ Included | Usually self-serve | Through dealers, paid | — |
| Typical yearly cost, one store | ₹4,999 | Free tier to paid yearly plans | Higher one-time + yearly renewal | ₹0, high hidden cost |
Category comparison based on publicly available plan information as of November 2026. Features and prices of individual products vary — check each vendor's current plans before deciding.
Simple yearly pricing. Every module included.
No per-bill fees, no per-user charges within your plan, no feature paywalls. Start with a free 30-day trial.
Free Trial
Try every feature on your own data.
No card required
- All modules unlocked
- Unlimited bills during trial
- GST invoice printing
- Data carries over when you upgrade
Standard
Everything a single store needs.
≈ ₹417 a month, billed yearly
- 1 store, 1 billing counter
- All modules: POS, inventory, batch/expiry, purchases, udhar
- Unlimited invoices & items
- Thermal & A4/A5 printing
- GSTR-1 / 3B exports
- Remote installation & email support
- Free updates for the year
Business
For busy stores with several counters.
≈ ₹1,083 a month, billed yearly
- Everything in Standard
- Multiple billing counters
- Local or cloud database setup
- Priority phone support
- Data migration assistance
- Staff training session
- Dedicated account manager
Billing from day one
Install
We install it remotely on your Windows 10/11 PC, or a local partner does it on-site.
Add your items
Import products from Excel/CSV or add them with barcode, HSN and GST rate.
Connect printer
Plug in your thermal printer and barcode scanner — no drivers to fight with.
Start billing
Ring up sales, record purchases, track udhar and watch your reports fill in.
Are you a GST consultant, accountant or IT dealer?
Join the Reynrel Partner Program. Recommend Billing OS to your clients, request installations from your own dashboard and earn commission on every approved sale and renewal.
Questions shop owners ask
Does Billing OS work without internet?
Yes. It runs on your computer with a local database, so billing, printing and reports keep working when the internet is down. Internet is only needed for activation, updates and WhatsApp sharing.
Can I make both B2B and B2C invoices?
Yes. Add the buyer's GSTIN for a B2B tax invoice, or bill walk-in customers as B2C. The tax split (CGST/SGST or IGST) is handled automatically and both are included in the GSTR-1 export.
Which computers and printers are supported?
Windows 10 and 11 PCs. 2-inch and 3-inch ESC/POS thermal printers, standard A4/A5 printers, and USB barcode scanners.
Can I use it on my phone?
Billing OS runs on your billing computer. The mobile view lets owners check sales, stock and udhar on the go — ask us about mobile access when you book your demo.
Is my data safe? Who owns it?
You do. Data is stored on your machine (or your own cloud database on the Business plan). One-click backup and restore are built in.
Can I move my data from my current software?
Item masters and opening stock can be imported from Excel/CSV. On the Business plan our team assists with migration.
What happens after the 30-day trial?
Choose Standard or Business to continue. Everything you entered during the trial stays.
What happens when my yearly plan ends?
You get renewal reminders inside the app with a grace period. Renew to keep receiving updates and support.
Start your free trial or book a live demo
Leave your number. Our team will call you, install Billing OS and show your staff how to bill in under 10 minutes.
- 30-day free trial, all modules
- Remote installation & setup help
- Support in English, Hindi and Assamese