As a User, I want to register using my email/mobile and password, so that I can securely access my expense data.

• Email/Mobile must be unique
• Password must satisfy minimum strength rules
• Mandatory fields missing হলে registration complete হবে না

As a User, I want to log in securely, so that I can manage my expenses and budgets.

• Wrong credentials → generic error message
• Multiple failed attempts → optional lock/delay (security)

As a User, I want to recover my password, so that I don’t lose access to my data.

• OTP / email verification required
• Reset token time-bound

As a User, I want to create expense category, so that I can organize my expenses and budgets according to my specific needs, and these categories will be available for selection during budget planning and expense entry.

Acceptance Criteria:

• Category name must be unique (case-insensitive validation)
• Category name cannot be empty or contain only whitespace
• Successfully created categories are marked as "Active" by default
• User receives confirmation message upon successful category creation
• Appropriate error messages are displayed for validation failures
• Maximum character limit for category name is defined (e.g., 50 characters)

As a User, I want to deactivate or reactivate expense categories (by selecting one from the list, see US-6), so that I can control which categories are available for new expense entries and budget planning while preserving historical data integrity.

Acceptance Criteria:

• Deactivated categories are hidden from selection lists during new expense entry and budget planning
• Deactivated categories remain visible in historical reports and existing expenses
• Existing expenses associated with a deactivated category retain their category assignment
• User can reactivate a previously deactivated category
• The system displays a confirmation prompt before deactivating a category
• Category status (Active/Inactive) is clearly indicated in the category list
• Deactivation does not delete the category or associated data

As a User, I want to view a comprehensive list of all categories with their current status, so that I can efficiently manage my category structure by updating names, activating, or deactivating categories as needed.

Acceptance Criteria:

• Display all categories in a list/table format with columns for: Category Name, Status (Active/Inactive), and Action (Edit)
• Provide search/filter functionality to find specific categories
• Category name uniqueness validation applies during updates
• Sort categories alphabetically or by status
• Changes are saved with appropriate confirmation messages

As a User, I want to record an expense with date, amount, and category.

• Amount must be positive
• Date cannot be in the future
• Category is mandatory

As a User, I want to be warned if I accidentally enter the same expense twice.

• Same Date + Amount + Category + Description → show warning (not block)

As a User, I want to edit or delete expenses if I made a mistake.

• Current year expenses → editable
• Previous year expenses → restricted / approval required (optional)

As a User, I want to define my budget for a specific category for a year, so that I can control my spending limits per category and track whether my expenses stay within the planned budget.

Acceptance Criteria:

• Budget amount must be a positive number (greater than zero)
• Only one budget can be set per year per category (duplicate year-category combination is not allowed)
• If no budget is set for a category in a given year, spending is treated as "Unlimited" (no restriction applied)
• User must select an active category and a valid year when setting the budget
• Deactivated categories are hidden from the category selection list during budget creation
• Users can update an existing budget only for the current year and are not allowed to update budgets from any previous year.
• Appropriate error messages are displayed for validation failures (e.g., non-positive amount, duplicate budget, etc)
• User receives a confirmation message upon successful budget creation or update
• Budget amount should support decimal values (e.g., 15000.50)
• The system displays the currency format consistently when showing budget amounts

As a User, I want to view the budget setup for the current year and also select a previous year to review past budgets, so that I can monitor my planned spending limits across all categories and make informed financial decisions.

Acceptance Criteria:

• By default, the system displays the budget setup for the current year
• User can select a different year from a dropdown/selector to view that year's budget
• Display budgets in a list/table format with columns for: Category Name, Budget Amount, and Status (Set/Unlimited)
• If no budget is set for a category in the selected year, the amount is displayed as "0" and marked as "Unlimited"
• Deactivated (hidden) categories are only displayed if they have a budget amount set for the selected year; otherwise, they are excluded from the list
• Deactivated categories with a budget value should be visually distinguished (e.g., grayed out or labeled as "Inactive")
• Provide search/filter functionality to find specific categories in the budget list
• Sort categories alphabetically or by budget amount
• Budget amounts are displayed in a consistent currency format

As a User, I want the system to enforce overspending rules based on policy.

• Soft Limit: allow expense, but mark as Over Budget
• Hard Limit (optional): beyond 100% requires approval note/document

As a User, I want to receive alerts when important budget events happen.

• In-app notifications default
• Email/SMS optional
• Anti-spam: same threshold/alert once per period

As a User, I want a monthly summary of my expenses, so that I can understand my spending patterns.

• Total spent
• Category breakdown
• Budget vs Spent vs Remaining
• Over-budget categories highlight

As a User, I want corrections handled properly, so that reporting stays accurate.

• Refund ≠ Negative Expense
• Use Adjustment entry instead (audit-friendly)

As a User, I want to filter expenses by date, category, or amount.

• Start date ≤ End date
• Invalid filters rejected

As a User, I want to see spending trends, so that I can make better decisions.

• Top spending categories
• High spending months
• Spending increase/decrease compared to previous period

As an Owner, I want to create a group with members, so that we can track shared expenses.

• Role-based access: Owner vs Member
• Owner sets budgets & policies

As an Owner, I want to approve over-budget expenses, so that spending stays controlled.

• Over-budget entries require owner approval (policy-based)
• Approval note/document may be required

এই প্রজেক্ট যদি SaaS এ Transform করা হয় তাহলে প্রতিদিন লক্ষ লক্ষ Expense Entry হবে, এক্ষেত্রে আমরা কিভাবে Daily Expense report এর লোডিং টাইম ১ মিনিটের পরিবর্তে ৩-৫ সেকেন্ডে নামিয়ে আনবো