Building an Automated Approval Workflow System with Blazor, .NET and Token-Based Actions
Introduction
Many business applications require processes where an action cannot be completed immediately and needs approval from another user or department.
Common examples include:
- Document approvals
- Purchase requests
- Change requests
- Service requests
- Internal workflows
Without automation, these processes often rely on emails, manual follow-ups, and disconnected systems.
This project focused on designing a reusable approval workflow system using Blazor, .NET, automated notifications, and secure token-based actions.
The goal was to create a flexible workflow where requests could be submitted, reviewed, approved, rejected, and tracked through their complete lifecycle.
The Challenge
Traditional approval processes often have several problems:
- Manual communication between users
- Lack of visibility into request status
- No centralized approval history
- Difficulty enforcing business rules
- No secure way for external users to respond
The system needed to provide:
- Automated approval routing
- Controlled state transitions
- Secure response links
- Notification handling
- Clear workflow tracking
System Architecture
The application was built using a layered architecture:
Blazor Frontend
|
|
Application Services
|
|
Workflow Engine
|
|
Database
|
|
Notification Service
Main components:
- Request Management UI
- Workflow Service
- Validation Layer
- Approval Handler
- Notification Service
- Token Validation System
Workflow Design
The workflow dynamically determines the required approval path based on predefined rules.
Example:
Request Created
|
↓
Validation
|
├── Approval Not Required
|
└── Approval Required
|
↓
Await Approval Decision
|
├── Approved
|
└── Rejected
This allows different workflows to be implemented without changing the core application structure.
State-Based Workflow Management
The system uses explicit states to control the lifecycle of each request.
Example:
Created
|
↓
Pending Approval
|
├── Approved
|
├── Rejected
|
↓
Completed
State management prevents invalid actions.
Examples:
- A rejected request cannot continue.
- A completed request cannot be modified.
- An approval step cannot be skipped.
This approach makes workflows easier to maintain and extend.
Secure Token-Based Actions
To simplify external approval scenarios, users can perform actions through secure email links without requiring a full application login.
Example:
/response?token=xxxx&action=approve
Each token includes:
- Random generated value
- Expiration timestamp
- Purpose identifier
- Usage status
Before processing a response, the system validates:
Token Exists ✓
Token Not Expired ✓
Token Not Used ✓
Correct Context ✓
After a successful action:
Token Used = True
This ensures that every approval action is secure and can only be performed once.
Component Architecture
The application was structured into reusable components.
Request Creation Component
Responsibilities:
- Data input
- Validation
- Workflow initialization
- Submission handling
Request Editing Component
Responsibilities:
- Loading existing requests
- Updating information
- Applying workflow restrictions
- Managing available actions
Response Component
Responsibilities:
- Token validation
- Processing approval decisions
- Updating workflow state
- Displaying feedback
Notification Service
Responsibilities:
- Sending automated emails
- Generating action links
- Informing users about workflow changes
Business Rule Enforcement
Rules were implemented at the application layer to ensure consistency.
Validation Rules
IF requirements are satisfied
Allow submission
ELSE
Request additional approval
Locking Rules
After reaching a final workflow stage:
Status = Completed
Result:
Read-only mode
This prevents unwanted changes after completion.
Technology Stack
Frontend
- Blazor
- Razor Components
- Component-based architecture
Backend
- .NET
- C#
- Service-oriented architecture
Data Layer
- Entity Framework Core
- SQL Database
Integration
- Email Services
- Token Authentication
- REST-based communication
Engineering Decisions
Why State Machines?
Using explicit workflow states provides:
- Better control
- Easier debugging
- Clear business rules
- Improved maintainability
Why Token-Based Actions?
Benefits:
- No additional login requirement
- Simple user experience
- Secure temporary access
- Audit-friendly actions
Benefits
The workflow system provides:
Automation
Reduces manual communication and repetitive tasks.
Transparency
Every request has a clear status and history.
Security
Approval actions are controlled through expiring one-time tokens.
Scalability
New workflow scenarios can be added without redesigning the entire system.
Conclusion
A modern approval system is more than a database record with a status field. It requires controlled state transitions, secure user actions, notifications, and clear business rules.
By combining Blazor, .NET, workflow logic, and token-based approvals, it is possible to build flexible enterprise applications that automate complex processes while maintaining security and traceability.
The same architecture can be applied to many scenarios, including document approvals, purchase workflows, change management, and internal request systems.