kunshort-django-wallet 1.0.0

Django wallet module with wallet models and services

kunshort-django-wallet 1.0.0

This repository contains a reusable Django app named wallets plus a small local-only Django project for development.

The installable package is intended for service consumption: wallet creation, beneficiary management, transfers, spending limits, activity history, and stable numeric error codes.

Package identity:

• Distribution name: kunshort-django-wallet
• Version: 1.0.0
• Python import path: wallets

What is included

• A Wallet model owned by user_id
• Automatic owner-beneficiary creation for every wallet
• Wallet creation accepts a 3-letter currency code
• Support for multiple wallets per user
• Dedicated wallet activity history via WalletActivities
• Dedicated beneficiary activity history via WalletBeneficiaryActivity
• Stored spending usage rows via WalletSpending
• Custom limit windows via CustomPeriod
• A WalletService class for wallet creation and retrieval
• A WalletTopUpService class for atomic wallet funding
• A WalletDebitService class for atomic wallet withdrawals
• A WalletTransactionHistoryService class for reading transaction history
• A WalletBeneficiaryService class for managing wallet beneficiaries
• A WalletBeneficiaryHistoryService class for beneficiary audit history and spending history
• A WalletTransferService class for beneficiary-only wallet transfers
• A WalletSpendingLimitService class for wallet and beneficiary spending rules
• Local development files for migrations, test execution, and optional API exploration

Wallet model behavior

• user_id is stored as a normalized string identifier
• A single user can create multiple wallets
• Wallet names are unique per user
• Wallet currency is stored as a normalized 3-letter code such as XAF or USD
• Wallets always start with a 0.00 balance at creation time
• If currency_code is not supplied during creation, XAF is used
• If name is omitted during creation, a generated name such as PrimaryWallet001 is used
• The first wallet for a user is always created as the default wallet
• Only one wallet per user can be marked as the default wallet at a time

Data model summary

• Wallet: the owned balance container. Includes default_wallet, currency_code, and balance.
• WalletBeneficiary: wallet-scoped participants. The owner is automatically stored here as is_owner=True.
• WalletTransaction: immutable wallet ledger rows. Uses a single user_id plus transaction_by to distinguish owner vs beneficiary actions.
• WalletActivities: wallet-wide audit log for create, top-up, debit, transfer, and spending-limit events.
• WalletBeneficiaryActivity: beneficiary-focused audit log for beneficiary add/remove, transfer-out, and beneficiary spending-limit events.
• WalletSpendingLimit: wallet-level or beneficiary-level spending rules.
• WalletSpending: persisted spending usage rows used when evaluating limits over time.
• CustomPeriod: custom active windows linked to WalletSpendingLimit when period="custom".

Identity rules

• There is only one user identifier field per record for wallet actors.
• The wallet owner is also a beneficiary of that wallet by default.
• WalletBeneficiary.user_id identifies the participant user.
• WalletTransaction.user_id identifies the acting user for that wallet transaction.
• WalletTransaction.transaction_by indicates whether the acting user is the owner or a beneficiary.
• WalletBeneficiaryActivity.user_id identifies the beneficiary user the activity is about.

Run locally

uv run python manage.py migrate
uv run python manage.py runserver

Management command

Create zero-balance wallets for existing users in the configured Django auth model:

uv run python manage.py create_system_wallets
uv run python manage.py create_system_wallets --wallet-name "Primary Wallet"
uv run python manage.py create_system_wallets --wallet-name "Primary Wallet" --currency "XAF"

The command reads users from Django's active auth user model via get_user_model() and only creates a wallet for users who do not already have one.

Build the package

Build the installable distribution from the project root:

uv build

The built artifacts are written to dist/.

The wheel now contains only the reusable wallets package. Development-only files such as the local Django project in config/, the optional API module, and the repository test suite are kept out of the installable package.

The packaged library still includes wallets.admin, so consumers who add wallets to INSTALLED_APPS will be able to view and manage the wallet models from Django admin.

To consume the package in another Django project:

pip install kunshort-django-wallet==1.0.0

Then add wallets to INSTALLED_APPS, run migrations, and import the service layer from wallets.services.

A minimal consumer integration walkthrough is available in CONSUMER_GUIDE.md.

Optional Test API

The repository also includes a DRF-based test API for local development, but it is not part of the packaged library.

• The API implementation lives in dev_api.py.
• DRF and OpenAPI dependencies are optional extras.
• All routes are mounted under /api/.
• Wallet-domain failures return the same numeric error codes documented in this README.

Start the server with:

uv sync --extra api
uv run python manage.py runserver

Open the interactive documentation at:

http://127.0.0.1:8000/api/docs/

The raw OpenAPI schema is available at:

http://127.0.0.1:8000/api/schema/

Example request:

curl -X POST http://127.0.0.1:8000/api/wallets/ \
	-H "Content-Type: application/json" \
	-d '{
		"user_id": "user-123",
		"name": "Primary Wallet",
		"currency_code": "XAF"
	}'

API endpoints

Wallets

Method	Path	Purpose
GET	/api/wallets/?user_id=...	List wallets for a user
POST	/api/wallets/	Create a wallet with zero opening balance
POST	/api/wallets/default/	Set a wallet as default
POST	/api/wallets/top-up/	Top up a wallet
POST	/api/wallets/debit/	Debit a wallet
GET	/api/wallets/history/?user_id=...&wallet_id=...	List wallet transaction history
GET	/api/wallets/user-history/?user_id=...	List all transactions for a user
GET	/api/wallets/activities/?user_id=...&wallet_id=...	List wallet-wide activity logs

Beneficiaries

Method	Path	Purpose
GET	/api/wallets/beneficiaries/?user_id=...&wallet_id=...	List beneficiaries for a wallet
POST	/api/wallets/beneficiaries/	Add a beneficiary
POST	/api/wallets/beneficiaries/remove/	Remove a non-owner beneficiary
GET	/api/wallets/beneficiary-wallet-history/?user_id=...&wallet_id=...&beneficiary_user_id=...	List beneficiary transactions inside one wallet
GET	/api/wallets/beneficiary-activities/?user_id=...&wallet_id=...	List beneficiary activity logs
GET	/api/wallets/beneficiary-spending-history/?user_id=...&wallet_id=...	List beneficiary spending-related activities

Transfers

Method	Path	Purpose
POST	/api/wallets/transfers/	Transfer funds from a wallet to a beneficiary-owned destination wallet

Spending limits

Method	Path	Purpose
GET	/api/wallets/spending-limits/?user_id=...&wallet_id=...	List wallet-level and beneficiary-level limits for a wallet
POST	/api/wallets/spending-limits/	Create or update a wallet-level spending limit
POST	/api/wallets/spending-limits/update/	Update a wallet-level spending limit by id
GET	/api/wallets/beneficiary-spending-limits/?user_id=...&wallet_id=...&beneficiary_user_id=...	List spending limits for one beneficiary
POST	/api/wallets/beneficiary-spending-limits/	Create or update a beneficiary-level spending limit
POST	/api/wallets/beneficiary-spending-limits/update/	Update a beneficiary-level spending limit by id

API response notes

• Successful responses return plain JSON objects or { "results": [...] } collections.
• Wallet-domain business errors return the documented wallet error payload with numeric codes.
• Basic request-validation failures return a generic request error payload from DRF-style validation handling.

Example service usage

from uuid import uuid4

from wallets.services import (
	WalletBeneficiaryHistoryService,
	WalletBeneficiaryService,
	WalletDebitService,
	WalletService,
	WalletSpendingLimitService,
	WalletTopUpService,
	WalletTransferService,
	WalletTransactionHistoryService,
)

from wallets.exceptions import serialize_wallet_error

wallet = WalletService.create_wallet(
	user_id=uuid4(),
	name="Primary Wallet",  # optional
	currency_code="XAF",   # optional, defaults to XAF
)

wallets = WalletService.list_wallets_for_user(user_id=wallet.user_id)

wallet = WalletService.set_default_wallet(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
)

wallet = WalletTopUpService.top_up_wallet(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
	amount="1500.00",
)

wallet = WalletDebitService.debit_wallet(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
	amount="250.00",
)

history = WalletTransactionHistoryService.list_wallet_history(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
)

beneficiary = WalletBeneficiaryService.add_beneficiary(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
	beneficiary_user_id=uuid4(),
	label="Trusted Recipient",
)

beneficiaries = WalletBeneficiaryService.list_wallet_beneficiaries(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
)

beneficiary_history = WalletBeneficiaryHistoryService.list_beneficiary_history(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
	beneficiary_user_id=beneficiary.user_id,
)

beneficiary_spending_history = WalletBeneficiaryHistoryService.list_beneficiary_spending_history(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
	beneficiary_user_id=beneficiary.user_id,
)

limit_rule = WalletSpendingLimitService.set_wallet_spending_limit(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
	limit_type="amount",
	period="daily",
	amount="5000.00",
)

beneficiary_limit_rule = WalletSpendingLimitService.set_beneficiary_spending_limit(
	user_id=wallet.user_id,
	wallet_id=wallet.id,
	beneficiary_user_id=beneficiary.user_id,
	limit_type="percentage",
	period="per_transaction",
	percentage="25.00",
)

source_transaction, destination_transaction = WalletTransferService.transfer_to_beneficiary(
	user_id=wallet.user_id,
	source_wallet_id=wallet.id,
	beneficiary_user_id=beneficiary.user_id,
	destination_wallet_id=uuid4(),  # replace with an actual beneficiary wallet id
	amount="100.00",
)

try:
	WalletDebitService.debit_wallet(
		user_id=wallet.user_id,
		wallet_id=wallet.id,
		amount="-10.00",
	)
except Exception as error:
	payload = serialize_wallet_error(error, flat=True)
	# {'erc': 303, 'msg': 'Amount must be greater than 0.'}

Django admin support

The installable package keeps the admin registrations for all wallet models.

To make the models visible in django-admin in a consuming project:

1. Install the package.
2. Add wallets to INSTALLED_APPS.
3. Ensure django.contrib.admin is enabled.
4. Run python manage.py migrate.
5. Create or use a superuser and open /admin/.

The following models are registered in admin:

• Wallet
• WalletTransaction
• WalletBeneficiary
• WalletActivities
• WalletBeneficiaryActivity
• WalletSpendingLimit
• WalletSpending
• CustomPeriod

Top-up validation

• The top-up service validates that the wallet belongs to the supplied user
• The top-up amount must be a valid decimal value greater than 0
• The balance update runs inside a database transaction and locks the wallet row during the update

Withdrawal and history

• The debit service uses the same ownership and amount validation rules as top-ups
• The debit service raises an error if the wallet balance is insufficient
• Every top-up and withdrawal writes a transaction history record with the amount, balance before, and balance after
• The history service can return all wallet transactions or filter by transaction type
• Beneficiary-linked transfers are also stored as wallet transactions, with the beneficiary user id written directly on the transaction row

Default wallet rules

• The first wallet created for a user is always the default wallet.
• Any later wallet created for the same user starts with default_wallet=False.
• A user cannot have two default wallets at the same time.
• Calling WalletService.set_default_wallet(...) makes the requested wallet the default and automatically sets the previous default wallet to False.

Beneficiaries

• Wallet owners can add beneficiaries to a specific wallet
• Beneficiary creation validates that the wallet belongs to the supplied user
• The wallet owner cannot be added manually as their own beneficiary because they already exist as the default owner-beneficiary
• The same beneficiary cannot be added twice to the same wallet
• The beneficiary service can list all beneficiaries attached to a wallet
• The beneficiary service can also remove a beneficiary from a wallet
• The owner-beneficiary cannot be removed from the wallet
• Beneficiary add, remove, transfer-out, and beneficiary limit events are written to the dedicated WalletBeneficiaryActivity history model using a single beneficiary user_id
• The beneficiary history service can return all beneficiary actions or only beneficiary spending history
• The wallet transaction history service can also return beneficiary-linked wallet transactions directly

Transfers and limits

• Transfers are only allowed to users already attached as beneficiaries on the source wallet
• The destination wallet used for a transfer must belong to the beneficiary user
• Transfers create matching transfer_out and transfer_in history records with the same reference id
• Wallet-level spending limits can be configured by fixed amount or percentage
• Beneficiary-level spending limits can be configured independently per wallet beneficiary
• Spending limits can be updated explicitly with dedicated update services
• Limits support per_transaction, daily, weekly, monthly, and custom periods
• Active beneficiary percentage limits for the same wallet and period cannot exceed 100%
• Re-running the same spending-limit rule updates the existing rule instead of creating duplicates
• Beneficiary limits are caps, not reserved balances, so the wallet owner can still spend from the wallet as long as the actual balance and wallet-level limits allow it

Error payloads

• Every wallet-domain exception now carries a stable error code and message
• Use serialize_wallet_error(error) for a nested payload: {"error": {"code": 303, "message": "..."}}
• Use serialize_wallet_error(error, flat=True) for a flat payload: {"erc": 303, "msg": "..."}
• The canonical message for a code is available through get_wallet_error_message(code) or the WALLET_ERROR_MESSAGES mapping
• Codes are stable identifiers for client applications and localization, even if the default English messages change later

Error code reference

The wallet module uses numeric codes so clients can localize messages independently of the default English text.

General

Code	Name	Default message
300	GENERIC	Wallet operation failed.

Amount and currency validation

Code	Name	Default message
301	INVALID_AMOUNT_FORMAT	Amount must be a valid decimal value.
302	INVALID_AMOUNT_NEGATIVE	Amount must be greater than or equal to 0.
303	INVALID_AMOUNT_NON_POSITIVE	Amount must be greater than 0.
304	INVALID_PERCENTAGE_FORMAT	Percentage must be a valid decimal value.
305	INVALID_PERCENTAGE_RANGE	Percentage must be greater than 0 and at most 100.
306	INVALID_CURRENCY_CODE	Currency code must be a valid 3-letter alphabetic code.

Ownership and beneficiary errors

Code	Name	Default message
307	WALLET_OWNERSHIP_MISMATCH	Wallet does not belong to the supplied user.
308	BENEFICIARY_NOT_FOUND	User is not attached to the supplied wallet.
312	OWNER_ALREADY_DEFAULT_BENEFICIARY	Wallet owner is already the default beneficiary.
313	DUPLICATE_BENEFICIARY	Beneficiary already exists for this wallet.
314	OWNER_BENEFICIARY_REMOVAL_FORBIDDEN	Wallet owner cannot be removed from the wallet beneficiaries.

Transfer errors

Code	Name	Default message
309	TRANSFER_DESTINATION_WALLET_MISMATCH	Destination wallet does not belong to the beneficiary user.
311	INSUFFICIENT_BALANCE_TRANSFER	Wallet balance is insufficient for this transfer.
328	TRANSFER_SOURCE_EQUALS_DESTINATION	Source and destination wallets must be different.

Balance and spending errors

Code	Name	Default message
310	INSUFFICIENT_BALANCE_DEBIT	Wallet balance is insufficient for this debit.
315	SPENDING_LIMIT_NOT_WALLET_LEVEL	The supplied spending limit is not a wallet-level limit.
316	SPENDING_LIMIT_NOT_BENEFICIARY_LEVEL	The supplied spending limit is not a beneficiary-level limit.
317	SPENDING_LIMIT_AMOUNT_REQUIRED	Amount is required for amount-based spending limits.
318	SPENDING_LIMIT_PERCENTAGE_REQUIRED	Percentage is required for percentage-based spending limits.
319	SPENDING_LIMIT_TYPE_UNSUPPORTED	Unsupported spending limit type.
320	SPENDING_LIMIT_VALIDATION_FAILED	Wallet spending limit configuration is invalid.
321	SPENDING_LIMIT_CUSTOM_PERIOD_REQUIRED	Custom period limits require both active_from and active_to.
322	SPENDING_LIMIT_CUSTOM_PERIOD_INVALID	active_to must be greater than active_from.
323	SPENDING_LIMIT_WALLET_MISMATCH	The supplied spending limit does not belong to the supplied wallet.
324	SPENDING_LIMIT_TOTAL_BENEFICIARY_PERCENTAGE_EXCEEDED	Total active beneficiary percentage limits for the same wallet and period cannot exceed 100%.
325	SPENDING_LIMIT_PER_TRANSACTION_EXCEEDED	Requested spend exceeds the configured per-transaction limit.
326	SPENDING_LIMIT_PERIOD_EXCEEDED	Requested spend exceeds the configured spending limit for the active period.
327	SPENDING_LIMIT_NO_ACTIVE_CUSTOM_PERIOD	No active custom period is configured for this spending limit.

Service reference

• WalletService.create_wallet(...): creates a wallet with zero opening balance, auto-creates the owner beneficiary, uses XAF when currency is omitted, auto-generates a name when one is not provided, and sets only the first wallet as default.
• WalletService.set_default_wallet(...): switches the default wallet for a user.
• WalletService.list_wallets_for_user(...): lists a user’s wallets.
• WalletTopUpService.top_up_wallet(...): credits a wallet owned by the supplied user.
• WalletDebitService.debit_wallet(...): debits a wallet owned by the supplied user and enforces spending limits.
• WalletTransactionHistoryService.list_wallet_history(...): returns wallet transaction history.
• WalletTransactionHistoryService.list_beneficiary_wallet_history(...): returns wallet transactions for a beneficiary user within one wallet.
• WalletBeneficiaryService.add_beneficiary(...): adds a new beneficiary to a wallet.
• WalletBeneficiaryService.remove_beneficiary(...): removes a non-owner beneficiary from a wallet.
• WalletBeneficiaryService.list_wallet_beneficiaries(...): lists all beneficiaries, including the owner-beneficiary.
• WalletBeneficiaryHistoryService.list_beneficiary_history(...): returns beneficiary activity history.
• WalletBeneficiaryHistoryService.list_beneficiary_spending_history(...): returns beneficiary spending-related activity only.
• WalletSpendingLimitService.set_wallet_spending_limit(...): creates or updates a wallet-level spending rule.
• WalletSpendingLimitService.set_beneficiary_spending_limit(...): creates or updates a beneficiary-level spending rule.
• WalletSpendingLimitService.update_wallet_spending_limit(...): updates a wallet-level spending rule by id.
• WalletSpendingLimitService.update_beneficiary_spending_limit(...): updates a beneficiary-level spending rule by id.
• WalletSpendingLimitService.list_wallet_spending_limits(...): lists all spending limits for a wallet.
• WalletSpendingLimitService.list_beneficiary_spending_limits(...): lists spending limits for one beneficiary in a wallet.
• WalletTransferService.transfer_to_beneficiary(...): transfers funds from a wallet to a beneficiary-owned destination wallet.