Case study: purchase bills from photos, checked by the e-invoice QR
A manufacturer joining Dravyaa had about 200 paper vendor bills to enter. Typing them meant weeks of work. Reading them from photos meant trusting AI with invoice numbers. The answer was the QR code already printed on the bill.
At a glance
- Each bill is photographed and read into a draft purchase bill: vendor, invoice number, date, lines, HSN, tax and total.
- On e-invoiced bills, the signed QR code carries the seller's GSTIN, invoice number, date and value. Dravyaa reads it and uses it over the AI's reading.
- In the first live test, the AI misread the invoice number on both bills. The QR corrected both.
- Missing vendors and items are proposed, not created silently. A person confirms them.
- A confirmed bill posts its stock and its accounting voucher like any bill entered by hand. A re-sent photo is caught as a duplicate.
AI can read a purchase bill. It can't be trusted on its own with the invoice number, which is the one field that must be exactly right. This manufacturer had about 200 vendor bills on paper to bring into Dravyaa when they started, and more arriving every week.
Why not just use OCR?
Reading a bill is the easy part. The hard part is everything the bill depends on. If the vendor or item doesn't exist in your masters yet, the bill can't be saved. And a single wrong character in an invoice number creates a bill your vendor's statement will never match. In the first live test, the model returned TMPL/4795/26-27 and AKC/2023-27582. Both were wrong.
What does the e-invoice QR code have to do with it?
Since e-invoicing, a B2B invoice from a larger supplier carries a QR code signed by the GST invoice registration portal. It encodes the supplier's and buyer's GSTINs, the document number and date, the invoice value, the main HSN code and the IRN. Dravyaa decodes that QR from the photo and uses it over anything the AI read. Both of the misread numbers above were corrected this way.
How does the flow work?
| Step | What Dravyaa does | Who decides |
|---|---|---|
| Photo | Takes the bill from a chat message or the mobile app's Scan Bill screen, at full resolution | Operator |
| Read | Extracts vendor, number, date, lines, HSN, tax and totals; decodes the e-invoice QR if there is one | Automatic |
| Check | Reconciles line totals, tax and the bill total, and compares with the QR | Automatic |
| Masters | Proposes any missing vendor or item | Operator confirms |
| Post | Creates the bill, adds the stock and posts the voucher | Operator confirms, or automatic when every check passes |
A bill posts without a tap only when all four checks pass, every master is already known and the QR was read. Anything else stops for review. The mobile app always shows the bill first, because a phone can.
Practical lessons
- Send the original image. Re-compressed photos, such as those forwarded through a messaging app, often destroy the QR.
- Confirm masters once. After the first bill from a vendor, its vendor and items are known, and later bills from them go faster.
- Duplicates are caught. Photographing the same bill twice doesn't create two bills.
Frequently asked questions
Can Dravyaa create a purchase bill from a photo?
Yes. A photo of a vendor bill is read into a draft purchase bill with vendor, invoice number, date, lines, HSN, tax and totals. After it passes its checks and is confirmed, it posts stock and the accounting voucher.
What information is in an e-invoice QR code?
The signed QR code on an e-invoice carries the supplier and buyer GSTINs, document number, type and date, the invoice value, the number of items, the main HSN code and the IRN.
What happens if a vendor isn't in Dravyaa yet?
Dravyaa proposes the missing vendor or item from the bill and waits for a person to confirm it. It never creates masters silently.
Why do forwarded photos sometimes fail?
Messaging apps often re-compress images, which can make the QR code unreadable. Send the original photo or a PDF.
About this case study
Customer names are withheld at the customer's request. Figures are taken from the customer's own Dravyaa account and source documents, not estimated. The flow was verified on the customer's real bills in September 2026.
Sources
Facts checked as of October 21, 2026. Rules change: confirm current requirements with the official source or your tax adviser.
Stop typing purchase bills
See a photographed bill become a posted purchase bill in a 20-minute walkthrough.