BillZap
GST bills in 30 seconds, even with no signal. Now live on Google Play.
Designed, built and grown by Dakshesh B, full-stack developer in Bangalore.
Sri Murugan Stores · Intra-state
- Sugar2 kg · HSN 1701 · 5%₹96.00
- Basmati rice5 kg · HSN 1006 · 5%₹475.00
- Sunflower oil1 L · HSN 1512 · 5%₹165.00
- to a finished GST bill
- 30s
- to a finished GST bill
- works without internet
- 100%
- works without internet
- Indian languages
- 12
- Indian languages
- forever, no trial
- ₹0
- forever, no trial
Overview
What is BillZap?
BillZap is a free GST billing and invoicing app for Android, made for small shops and traders in India, and it is now live on Google Play. It makes GST-compliant tax invoices with HSN codes and an automatic CGST, SGST or IGST split, prints a UPI QR code so the customer can pay on the spot, and shares the bill as a PDF on WhatsApp. It works fully offline, needs no sign-up, keeps every record on the phone and supports voice billing. I built the roughly 26,000-line Flutter app and its website end to end.
Features
What BillZap does
- 01
Offline GST invoices
Saved on the phone instantly with nothing waiting to sync, and no account, phone number or email needed.
- 02
Automatic CGST, SGST or IGST
Per-item GST at 0, 5, 12, 18, 28 or 40 percent, with the place of supply deciding the split and HSN/SAC codes on every line.
- 03
UPI QR on every unpaid bill
Customers scan and pay before they leave, and the money goes straight to your bank. BillZap is not in the middle of the payment.
- 04
WhatsApp PDF in two taps
Share the invoice as a PDF on WhatsApp, or print it on a WiFi or Bluetooth printer.
- 05
Voice billing
Speak the order, such as "do kilo chini", and BillZap turns it into a line item with HSN code and GST.
- 06
Reports and day close
GSTR-1 summary export (PDF and CSV), profit and loss, dues ledger with WhatsApp reminders, stock alerts and a daily cash close.
For engineers and recruiters
How I built it
- A roughly 26,000-line Flutter app that creates GST-compliant invoices fully offline, with no account or server.
- UPI QR codes, WhatsApp PDF sharing, WiFi and Bluetooth printing, voice billing and PIN or fingerprint app lock.
- The billzap.app website on Cloudflare Workers with a PostgreSQL-backed blog, JSON-LD and llms.txt, a Lighthouse performance score of 100 and a 500+ check Playwright suite on every deploy.
Tech stack
- Flutter
- Dart
- Riverpod
- go_router
- Hive
- PDF generation
- Speech to text
- local_auth
- Cloudflare Workers
- Neon PostgreSQL
- Playwright
- GitHub Actions
FAQ
BillZap questions
- Is BillZap available on Google Play?
- Yes. BillZap is live on Google Play as a free download for Android at play.google.com/store/apps/details?id=com.billzap.app.
- Is BillZap really free?
- Yes. There is no paid tier, no expiring trial and no invoice limit.
- Does BillZap work without internet?
- Completely. Everything is stored on the phone, so you can bill with no signal and nothing is queued to sync.
- How does the UPI QR work?
- Set your UPI ID once and every unpaid invoice carries a QR code any UPI app can scan. The money goes straight to your bank.
- Who built BillZap?
- BillZap was designed and built end to end by Dakshesh B, a full-stack and Flutter developer based in Bangalore.
More products
Hiring a developer in Bangalore?
I am open to full-time Full-Stack, Frontend and SEO Engineer roles, and ready to relocate anywhere. I also take on a few freelance projects.