Finance & Payments
Invoicing and Billing Management System
A billing system for quotations, one-off and recurring invoices, credit notes, receipts and customer statements, with ageing reports and automatic reminders for overdue accounts.
- Web-based
- Android
Overview
Invoicing and Billing Management System
Businesses that bill from word-processor templates or spreadsheets often lose track of what has been invoiced, what is overdue and which payments relate to which invoice. Recurring charges are forgotten, invoice numbers are duplicated, and chasing debtors depends on memory. An Invoicing and Billing Management System makes billing consistent and collections visible.
Extrion Tech develops the system around how you charge: fixed price lists, hourly or metered services, monthly subscriptions, contracts with milestones, or a combination. Quotations convert into invoices, recurring invoices generate on schedule, and taxes, discounts and multiple currencies are applied according to rules agreed with you. Invoices are emailed as branded PDFs, and fiscal receipt generation through an EFD or VFD service can be included where the provider offers an API and it is within project scope.
Payments received by bank, cash, card or mobile money are recorded against invoices, and customer statements and ageing reports show exactly who owes what. Automatic reminders go out before and after due dates by email or SMS. The system suits service companies, property managers, schools and utilities in Zanzibar and across Tanzania, and can pass invoices and receipts to an accounting system so the books stay aligned.
Business problems it addresses
- Invoices are prepared in templates, causing duplicated numbers and calculation errors.
- Recurring monthly charges are missed or billed late.
- Payments cannot easily be matched to the invoices they settle.
- Debtors are chased inconsistently, so cash collection is slow.
- Customers request statements that take time to compile by hand.
Interface
Five screens of the system
Illustrative mockups with sample data — not screenshots of a client’s system.
Workflow
From quotation to paid invoice
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1
Customer and price setup
Customers, price lists, tax rules and billing terms are recorded once.
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2
Quotation
A branded quotation is issued and tracked until accepted or expired.
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3
Invoice generation
Accepted quotes, deliveries or recurring schedules produce numbered invoices.
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4
Fiscal receipt, if required
Where integrated, the invoice is submitted to the fiscal service and its reference stored.
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5
Delivery to customer
The invoice is emailed as a PDF or shared through the customer portal.
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6
Payment and receipting
Payments are recorded against invoices and receipts are issued automatically.
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7
Reminders and statements
Overdue invoices trigger reminders, and statements summarise each account.
Functions covered
Modules and what they do
01 Billing
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Customers and price lists
Holds customer accounts, credit terms and product or service prices.
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Quotations
Creates, sends and tracks quotations through to acceptance.
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Invoices
Issues one-off, recurring and milestone invoices with sequential numbering.
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Credit notes
Reverses or adjusts invoices with an approval and reason.
02 Collections
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Receipts and allocation
Records payments and allocates them to one or more invoices.
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Statements and ageing
Produces customer statements and debtors ageing by period.
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Reminders
Sends scheduled email or SMS reminders before and after due dates.
03 Integrations
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Fiscal receipt service
Optional / subject to scope
Submits invoices to an EFD/VFD service where an API is available.
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Online and mobile payments
Optional / subject to scope
Accepts payment links or mobile money where the provider offers an API.
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Customer portal
Optional / subject to scope
Lets customers view invoices, statements and download receipts.
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Accounting export
Optional / subject to scope
Passes invoices and receipts to the accounting system.
Technology stack
Technology selected for this solution
These are the technologies planned for this type of system. The final stack depends on scale, performance, licensing, infrastructure, integrations and your requirements.
Frontend
Backend
Database
Infrastructure
Integrations
Security & data integrity
Protecting your data and its accuracy
Customer billing and payment records are commercially sensitive, so issuing credit notes and editing prices are restricted to authorised roles. Invoice retention and tax record requirements are agreed with the client for the relevant jurisdiction.
Standard protections
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Role-based access control
Each user sees only what their role allows.
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Authentication and authorisation
Every request is checked for a signed-in, permitted user.
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Fine-grained permissions
Permissions per module and action, such as view, edit or approve.
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Secure password storage
Passwords are stored using strong one-way hashing, never in plain text.
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Encryption in transit
HTTPS/TLS protects data between users and the server.
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Server-side input validation
All input is validated on the server before it is saved.
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Protection against common web vulnerabilities
Defences against injection, cross-site scripting and request forgery.
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Database constraints and transactions
Constraints and transactions keep related records consistent.
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Audit logs
Important actions are recorded with who, what and when.
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User activity history
A history of each user’s activity for supervisors and administrators.
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Backup and restoration
Scheduled backups with tested restoration procedures.
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Session management
Session time-outs and the ability to sign out other devices.
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Secure API access
Authenticated, rate-limited access for integrations.
Optional advanced protections
- Multi-factor authentication A second sign-in step for selected or all users.
- Encryption at rest Sensitive data encrypted on disk where the infrastructure supports and is configured for it.
- Data retention and deletion policies Retention periods and deletion rules agreed with you.
- Data export controls Exports limited to authorised roles and recorded.
Data integrity
Invoice numbers are allocated by the database in an unbroken sequence, and issued invoices are never edited, only adjusted by credit notes. Receipt allocations must equal the amount received, and customer balances are recalculated from transactions so statements always reconcile with ageing reports.
Security controls are configured for each project. We do not claim certification, compliance or immunity from attack unless independently verified for your deployment.
Customisation & integration
Tailored to how you work
We tailor modules, reports, permissions, workflows, branding and integrations to your organisation. Tell us which features you need when you request a quote.
- Invoice, quotation and receipt templates with branding
- Billing models: recurring, metered or milestone
- Tax, discount and currency rules
- Reminder schedule and message wording
- Fiscal, payment and accounting integrations
Deployment & support
From go-live to continuous improvement
Onboarding, data migration, training, maintenance, technical support and future enhancements are services we scope into your project.
Bringing records from spreadsheets or older systems, checked and reconciled.
Role-based training for users, supervisors and administrators.
Technical support and maintenance under an agreed support plan.
New modules, reports and integrations as your organisation grows.
Pricing
Pricing tailored to your requirements
Every organisation has different workflows, users, infrastructure, and integration needs. Request a quotation for a solution designed around your requirements.
- Number of users, branches and modules
- Customisation and integrations
- Hosting: cloud, your server or hybrid
- Data migration and training
- Support and maintenance plan
Finance & Payments
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