UdhaarBill data API: GST invoices and udhaar

Collibet India · Business

Khatabook Credit Account Book is Collibet India's digital khata and GST billing app for Indian kirana shops, garment traders and other MSMEs who still keep customer udhaar on paper. Listed on Play under package com.udhaarbill and branded inside the client as Billy, it replaces the bahi-khata with a customer and supplier ledger, GST or non-GST invoices, a product catalogue with HSN codes and unit types, WhatsApp payment reminders, a UPI QR on the bill, and Bluetooth thermal-printer receipts. Books live first in an encrypted on-device database so creating parties and invoices works offline; Google Sign-In unlocks cloud backup, multi-device sync, analytics (top debtors, collection efficiency, GST summary, payment-mode mix) and reminder templates as a Razorpay-billed Premium plan. The shop-profile screen stores logo, signature, GSTIN and invoice prefix so every PDF is ready to share, and the UI ships in English plus ten Indian languages (Hindi, Bengali, Gujarati, Kannada, Malayalam, Marathi, Odia, Punjabi, Tamil, Telugu). It sits in the same MSME billing niche as Khatabook, OkCredit, Vyapar and myBillBook, aimed at owners who want a phone-sized credit book rather than a desktop Tally setup.

Party outstanding on the khata stamps balance_due and outstanding_amount against customer_gstin, while GST bills carry invoice_number, gst_total and line-level hsn_code. Cloud sync copies those ledger rows between devices; Razorpay Checkout then flips is_premium and premium_expiry so backup, analytics and reminder templates stay on. Collection dashboards, GSTR-1 workbooks and a second billing counter all read the same party and invoice fields. openData Studio turns that surface into callable open data.

Screenshots

API surface

The endpoints and request/response examples below are reconstructed from the app's interface — illustrative, not a live capture.

Sign in with Google id_token
POST /v1/sessions/exchange osint
Exchanges a Google Sign-In id_token for the merchant session used by profile, device, sync and Razorpay calls. The returned auth_token is the Bearer value on every later request.
Auth: Unauthenticated bootstrap. Body carries the Google Sign-In id_token; the response auth_token is sent as Authorization: Bearer on later calls, with X-App-Version.
- id_token
- device_id
- auth_token
- refreshToken
- uid
- email
- displayName
- is_premium
- premium_expiry
```
POST /v1/sessions/exchange HTTP/1.1
Content-Type: application/json
X-App-Version: 1.1.2

{
  "id_token": "eyJhbGciOiJSUzI1NiIsImtpZCI6Imdvb2dsZS1leCJ9.example",
  "device_id": "a1b2c3d4e5f6"
}
```
```
{
  "auth_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.example",
  "refreshToken": "rt_7c11ab",
  "uid": "usr_9f2a",
  "email": "[email protected]",
  "displayName": "Ramesh Kirana",
  "is_premium": false,
  "premium_expiry": null
}
```

Read signed-in merchant profile

GET /v1/merchant/shop-profile osint

Returns the signed-in merchant card shown on Settings: shop identity, GSTIN, UPI id, premium flag and last successful cloud sync.

Auth: Authorization: Bearer <auth_token> from POST /v1/sessions/exchange, plus X-App-Version.

uid
email
displayName
shop_name
shop_phone
shop_address
gstin
upi_id
is_premium
premium_expiry
last_sync_at

GET /v1/merchant/shop-profile HTTP/1.1
Authorization: Bearer <auth_token>
X-App-Version: 1.1.2

{
  "uid": "usr_9f2a",
  "email": "[email protected]",
  "displayName": "Ramesh Kirana",
  "shop_name": "Ramesh Kirana Store",
  "shop_phone": "9876543210",
  "shop_address": "12 MG Road, Pune",
  "gstin": "27AABCU9603R1ZX",
  "upi_id": "ramesh@okaxis",
  "is_premium": true,
  "premium_expiry": "2027-03-14T00:00:00Z",
  "last_sync_at": "2026-10-17T08:12:00Z"
}

Register device, FCM token and Play Integrity
POST /v1/account/devices osint
Binds the phone that holds the on-device books: FCM for reminder and sync-alert pushes, Play Integrity attestation, and the device_id used on later sync calls.
Auth: Authorization: Bearer <auth_token>. A Play Integrity attestation token and the device's FCM push token ride in the body.
- device_id
- device_name
- device_model
- fcm_token
- integrityToken
- status
- syncDeviceTelemetry
```
POST /v1/account/devices HTTP/1.1
Authorization: Bearer <auth_token>
Content-Type: application/json
X-App-Version: 1.1.2

{
  "device_id": "a1b2c3d4e5f6",
  "device_name": "Pixel 7",
  "device_model": "GP4BC",
  "fcm_token": "fcm-ex-44120",
  "integrityToken": "PI_TOKEN_EXAMPLE"
}
```
```
{
  "device_id": "a1b2c3d4e5f6",
  "status": "REGISTERED",
  "syncDeviceTelemetry": true
}
```
Sign out merchant session
POST /v1/sessions/revoke osint
Ends the Google session from the Settings log-out tile and drops the device binding so FCM reminder pushes stop.
Auth: Authorization: Bearer <auth_token> from POST /v1/sessions/exchange.
- device_id
- status
- uid
```
POST /v1/sessions/revoke HTTP/1.1
Authorization: Bearer <auth_token>
X-App-Version: 1.1.2
Content-Type: application/json

{
  "device_id": "a1b2c3d4e5f6"
}
```
```
{
  "status": "SIGNED_OUT",
  "uid": "usr_9f2a"
}
```

Push local khata, invoices and catalogue

POST /v1/ledger/changes openfinance

Uploads unsynced on-device ledger rows — customers, invoices, line items, products and payments — so Premium cloud backup can restore them on another device.

Auth: Authorization: Bearer <auth_token>. Premium cloud-sync entitlement (is_premium) is required; free mode keeps rows on-device only.

device_id
customer_id
customer_name
customer_phone
customer_gstin
is_supplier
outstanding_amount
invoice_number
due_date
subtotal
gst_percent
gst_amount
gst_total
total_amount
paid_amount
balance_due
hsn_code
qty
rate
is_synced
last_sync_at
hasUnsyncedChanges

POST /v1/ledger/changes HTTP/1.1
Authorization: Bearer <auth_token>
Content-Type: application/json
X-App-Version: 1.1.2

{
  "device_id": "a1b2c3d4e5f6",
  "customers": [
    {
      "customer_id": "c-88a1",
      "customer_name": "Mona Traders",
      "customer_phone": "9876501234",
      "customer_gstin": "27AAPCM1234F1Z5",
      "customer_address": "Lane 4, Camp, Pune",
      "is_supplier": false,
      "outstanding_amount": 12500.0,
      "is_synced": false,
      "updated_at": "2026-10-17T07:40:00Z"
    }
  ],
  "invoices": [
    {
      "invoice_id": "inv-441",
      "invoice_number": "KB-2026-0441",
      "invoice_date": "2026-10-16",
      "due_date": "2026-10-30",
      "customer_id": "c-88a1",
      "subtotal": 11800.0,
      "discount_percent": 0,
      "discount_amount": 0,
      "gst_percent": 18,
      "gst_amount": 2124.0,
      "gst_total": 2124.0,
      "total_amount": 13924.0,
      "paid_amount": 1424.0,
      "balance_due": 12500.0,
      "is_gst": true,
      "status": "pending",
      "payment_method": "upi",
      "is_synced": false
    }
  ],
  "invoice_items": [
    {
      "invoice_id": "inv-441",
      "product_id": "p-ata-1",
      "product_name": "Ashirvaad Atta 10kg",
      "hsn_code": "1101",
      "qty": 4,
      "rate": 2950.0,
      "gst_percent": 18,
      "gst_amount": 2124.0
    }
  ],
  "products": [],
  "payments": []
}

{
  "status": "ACCEPTED",
  "hasUnsyncedChanges": false,
  "last_sync_at": "2026-10-17T08:12:00Z",
  "synced": {
    "customers": 1,
    "invoices": 1,
    "invoice_items": 1,
    "products": 0,
    "payments": 0
  }
}

Pull cloud khata snapshot

GET /v1/ledger/snapshot openfinance

Downloads the cloud books after Google Sign-In or Restore from cloud, including shop GST settings and the customer / invoice / product rows that fill the home, Customers and Invoices tabs.

Auth: Authorization: Bearer <auth_token>. Same Premium cloud-sync gate as /v1/ledger/changes.

last_sync_at
shop_name
gstin
invoice_prefix
invoice_counter
default_gst_rate
customers
outstanding_amount
invoices
invoice_number
balance_due
gst_total
products
hsn_code
rate
payments

GET /v1/ledger/snapshot?device_id=a1b2c3d4e5f6&last_sync_at=2026-10-16T18:00:00Z HTTP/1.1
Authorization: Bearer <auth_token>
X-App-Version: 1.1.2

{
  "last_sync_at": "2026-10-17T08:12:00Z",
  "shop_name": "Ramesh Kirana Store",
  "gstin": "27AABCU9603R1ZX",
  "invoice_prefix": "KB",
  "invoice_counter": 441,
  "default_gst_rate": 18,
  "customers": [
    {
      "customer_id": "c-88a1",
      "customer_name": "Mona Traders",
      "customer_phone": "9876501234",
      "customer_gstin": "27AAPCM1234F1Z5",
      "is_supplier": false,
      "outstanding_amount": 12500.0,
      "is_synced": true
    }
  ],
  "invoices": [
    {
      "invoice_id": "inv-441",
      "invoice_number": "KB-2026-0441",
      "balance_due": 12500.0,
      "gst_total": 2124.0,
      "status": "pending",
      "is_gst": true
    }
  ],
  "products": [
    {
      "product_id": "p-ata-1",
      "product_name": "Ashirvaad Atta 10kg",
      "hsn_code": "1101",
      "rate": 2950.0,
      "gst_percent": 18
    }
  ],
  "payments": []
}

Read Razorpay checkout config

GET /v1/premium/checkout-config openbanking

Returns the Razorpay key and Premium plan amounts that the upgrade screen feeds into Checkout before creating an order.

Auth: Authorization: Bearer <auth_token>. Used before the Premium upgrade sheet opens Razorpay Checkout.

key_id
currency
name
description
theme_color
plan_id
amount
period

GET /v1/premium/checkout-config HTTP/1.1
Authorization: Bearer <auth_token>
X-App-Version: 1.1.2

{
  "key_id": "rzp_test_<key_id>",
  "currency": "INR",
  "name": "UdhaarBill Premium",
  "description": "Cloud backup, analytics, reminder templates",
  "theme_color": "#0783B4",
  "plans": [
    {
      "plan_id": "premium_annual",
      "amount": 99900,
      "currency": "INR",
      "period": "yearly"
    }
  ]
}

Create Razorpay Premium order

POST /v1/premium/orders openbanking

Creates the Razorpay order the Checkout sheet charges; order_id is posted back on the verify call after payment.

Auth: Authorization: Bearer <auth_token> from POST /v1/sessions/exchange.

plan_id
order_id
amount
currency
receipt
status

POST /v1/premium/orders HTTP/1.1
Authorization: Bearer <auth_token>
Content-Type: application/json
X-App-Version: 1.1.2

{
  "plan_id": "premium_annual",
  "amount": 99900,
  "currency": "INR"
}

{
  "order_id": "order_N7example",
  "amount": 99900,
  "currency": "INR",
  "receipt": "ub-prem-usr_9f2a",
  "status": "created"
}

Verify Razorpay payment and unlock Premium
POST /v1/premium/confirmations openbanking
Confirms the Checkout signature on the server and flips is_premium so cloud sync, analytics and reminder templates unlock. A failed verification surfaces as a payment error on the upgrade screen.
Auth: Authorization: Bearer <auth_token>. Body is the Checkout success payload (razorpay_order_id, razorpay_payment_id, razorpay_signature).
- razorpay_order_id
- razorpay_payment_id
- razorpay_signature
- status
- is_premium
- premium_expiry
- subscriptionActiveUntil
```
POST /v1/premium/confirmations HTTP/1.1
Authorization: Bearer <auth_token>
Content-Type: application/json
X-App-Version: 1.1.2

{
  "razorpay_order_id": "order_N7example",
  "razorpay_payment_id": "pay_N8example",
  "razorpay_signature": "a1b2c3d4e5f6signature"
}
```
```
{
  "status": "VERIFIED",
  "is_premium": true,
  "premium_expiry": "2027-10-17T00:00:00Z",
  "subscriptionActiveUntil": "2027-10-17T00:00:00Z"
}
```

Data categories

parties
invoices
gst
inventory
payments
sync

Where teams use this data

AR collection queue from the khata
A collections bot reads outstanding_amount, balance_due, due_date and customer_phone from the synced party rows, then opens the same WhatsApp reminder the shopkeeper sends from the customer-detail screen — without re-keying the ledger.
GST return prep from invoice lines
A CA workbook joins invoice_number, customer_gstin, hsn_code, gst_percent, gst_amount and gst_total on is_gst invoices so GSTR-1 line items match the PDFs the shop already shared.
Catalogue rate card across counters
A second billing counter pulls product_name, hsn_code, rate and gst_percent from the cloud catalogue after a sync pull, so HSN and GST% stay identical to the owner's phone.
Premium entitlement after Razorpay
Billing ops matches razorpay_payment_id and razorpay_order_id against is_premium and premium_expiry to confirm cloud-sync seats without opening the upgrade screen.

Frequently asked questions

How does the app authenticate merchants?

Google Sign-In mints an id_token that POST /v1/sessions/exchange swaps for auth_token and refreshToken. Later calls send Authorization: Bearer plus X-App-Version. POST /v1/account/devices then binds device_id, fcm_token and a Play Integrity token.

Which fields describe a customer's udhaar balance?

Synced party rows expose customer_name, customer_phone, customer_gstin, is_supplier, outstanding_amount and, on each invoice, balance_due, paid_amount, due_date and status (pending, paid, overdue).

How are GST invoices represented?

Each invoice has invoice_number, is_gst, gst_percent, gst_amount, gst_total, subtotal and total_amount. Line items add hsn_code, qty, rate and product_name. Shop defaults live as gstin, default_gst_rate, invoice_prefix and invoice_counter.

What does Razorpay unlock?

GET /v1/premium/checkout-config and POST /v1/premium/orders start Checkout; POST /v1/premium/confirmations returns is_premium and premium_expiry, which gate POST /v1/ledger/changes and GET /v1/ledger/snapshot cloud backup.

Apps similar to Khatabook Credit Account Book

Khatabook — Khatabook is a digital ledger for Indian micro and small merchants that records debit and credit, takes UPI and QR payments, and sends automatic payment reminders with a payment link.
OkCredit — OkCredit is a paperless udhar bahi-khata for Indian shopkeepers that logs customer credit and payments on the phone and sends collection reminders over WhatsApp and SMS.
Vyapar Invoice GST Billing App — Vyapar is an Indian GST billing, accounting and inventory app for MSMEs that creates tax invoices, tracks stock and payments, and syncs books between a phone and a desktop client.
myBillBook Invoice Billing App — myBillBook is GST billing software for Indian small businesses that creates GST and non-GST invoices with HSN/SAC codes, tracks inventory, and sends WhatsApp or SMS payment reminders with UPI links.
TallyPrime — TallyPrime is Tally Solutions' business-management software for Indian firms, covering books, GST invoices and returns, inventory and connected banking in a desktop-first setup.
Zoho Books — Zoho Books is Zoho's GST-compliant cloud accounting product for Indian businesses, covering invoicing, e-invoicing, inventory, banking and GST filing from web and mobile apps.
Swipe — Swipe is GST invoicing, POS and inventory software for Indian SMEs that creates invoices and quotations, shares bills on WhatsApp, and records stock-in and stock-out.
BUSY — BUSY is accounting and GST billing software for Indian MSMEs, with invoicing, inventory, e-invoicing, e-way bills and a mobile app for quotations, orders and invoices.

More Business apps

Topics

udhaarbill api
billy khata
gst invoice fields
balance_due
customer_gstin
hsn_code
razorpay premium
india msmes billing

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UdhaarBill data API: GST invoices and udhaar

Screenshots

API surface

Sign in with Google id_token

Read signed-in merchant profile

Register device, FCM token and Play Integrity

Sign out merchant session

Push local khata, invoices and catalogue

Pull cloud khata snapshot

Read Razorpay checkout config

Create Razorpay Premium order

Verify Razorpay payment and unlock Premium

Data categories

Where teams use this data

AR collection queue from the khata

GST return prep from invoice lines

Catalogue rate card across counters

Premium entitlement after Razorpay

Frequently asked questions

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UdhaarBill data API: GST invoices and udhaar

Screenshots

API surface

Sign in with Google id_token

Read signed-in merchant profile

Register device, FCM token and Play Integrity

Sign out merchant session

Push local khata, invoices and catalogue

Pull cloud khata snapshot

Read Razorpay checkout config

Create Razorpay Premium order

Verify Razorpay payment and unlock Premium

Data categories

Where teams use this data

AR collection queue from the khata

GST return prep from invoice lines

Catalogue rate card across counters

Premium entitlement after Razorpay

Frequently asked questions

Related apps

Apps similar to Khatabook Credit Account Book

More Business apps

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Need this app's data API integrated?