---
title: "Build Your First Approval Workflow in ASP.NET Zero"
description: "Learn how to build, test and run a leave request approval workflow with the new workflow and approval builder in ASP.NET Zero v15.5, using a form, role-based approvals, a condition and notifications, without writing any code."
url: "https://aspnetzero.com/blog/build-your-first-approval-workflow-in-aspnet-zero"
image: "https://aspnetzero.com/Images/Blog/workflow-approval-builder-cover_f698.webp"
---

[Blog](https://aspnetzero.com/blog)

# Build Your First Approval Workflow in ASP.NET Zero

04 November 2026 9 min read

![Build Your First Approval Workflow in ASP.NET Zero](https://aspnetzero.com/Images/Blog/workflow-approval-builder-cover_f698.webp)

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Almost every business application eventually needs approvals. Someone requests leave, a purchase or a document review, and one or more people have to decide on it. These processes often start in email and spreadsheets, or they turn into custom code that has to change every time the process does.

[ASP.NET Zero v15.5](https://aspnetzero.com/blog/introducing-asp.net-zero-v15.5) includes a **built-in workflow and approval builder** for exactly this. Tenant administrators design request types in a visual designer, employees start requests from a catalog, and approvers decide on them from their inbox. The feature works the same way in the MVC, Angular and React UIs.

In this post, we will build a **leave request** workflow from scratch, publish it and run it end to end, without writing any code.

![The finished leave request workflow](https://aspnetzero.com/Images/Blog/workflow-designer-flow.png)

## The Scenario

Employees should request leave in the application instead of by email, with these rules:

- Every request is approved by a **team lead**.
- Requests for **more than 5 days** are also approved by **HR**.
- An approver who spots a mistake can send the request **back to the requester for changes** instead of rejecting it.
- The employee is notified when the leave is approved.

We will use four users:

| User | Role | Purpose |
| --- | --- | --- |
| `admin` | Admin | Designs and publishes the workflow |
| `alice` | Employees | Requests leave |
| `bob` | Team Leads | Team lead approval |
| `carol` | HR | HR approval |

## Step 1: Prepare Roles and Users

Workflow pages are tenant pages, so log in to a tenant as `admin`. Under **Administration > Roles**, create three roles and grant these permissions:

| Role | Permission |
| --- | --- |
| **Employees** | Workflows > Workflow Requests > **Starting workflow requests** |
| **Team Leads** | Workflows > Approval Inbox > **Acting on workflow tasks** |
| **HR** | Workflows > Approval Inbox > **Acting on workflow tasks** |

Then create `alice`, `bob` and `carol` under **Administration > Users** and assign each user their role.

> By default, nobody can approve their own request, so use separate users for the requester and the approvers.

## Step 2: Create the Workflow

Go to **Workflows > Workflow Administration > Workflow Definitions** and click **New workflow**. Enter `Leave request` as the display name, set the category to `HR` and choose **Start blank**.

![New workflow dialog](https://aspnetzero.com/Images/Blog/workflow-new-dialog.png)

The dialog also offers **Start from a template**. Every tenant starts with ready-made **Leave request**, **Expense claim** and **Purchase request** templates, and you can save your own designs as templates too. The built-in Leave request template is very close to what we are building here, so you can use it as a shortcut once you know how the pieces fit together. You only need to assign its approvers.

![Workflow Templates page](https://aspnetzero.com/Images/Blog/workflow-templates.png)

## Step 3: Build the Form

The **Workflow Designer** has four tabs: **Flow**, **Form**, **Trigger** and **Simulation**. Open the **Form** tab, click a field type to add it, and set its properties on the right:

| Label | Field type | Properties |
| --- | --- | --- |
| Leave type | Single select | Options: `Annual`, `Excuse`, `Sick`. Required |
| Start date | Date | Required |
| End date | Date | Required |
| Number of days | Number | Required, minimum value `1` |
| Description | Long text |  |

Each field also has a **Key**, such as `numberOfDays`. Conditions and integrations use this key to refer to the field.

![The form builder](https://aspnetzero.com/Images/Blog/workflow-form-builder.png)

## Step 4: Draw the Flow

Open the **Flow** tab. The steps palette on the left groups the available step types. Add a **Start**, a **Form**, two **Approval** steps named `Team lead approval` and `HR approval`, a **Condition**, a **Notification** named `Notify the requester`, and the **Approved** and **Rejected** outcomes.

Now configure the steps that need settings.

**Approvals:** Select each approval step, open the **Assignment** tab and add the assignee. We use the **Team Leads** role for the first approval and the **HR** role for the second. An approval step can also be assigned to a specific user, an organization unit or the requester's manager.

![Assigning an approval to a role](https://aspnetzero.com/Images/Blog/workflow-approval-assignment.png)

The **Behaviour** tab controls how the decision is made. Its defaults fit this scenario: **Anyone can decide**, **Allow "request changes"** is on and a reason is required when rejecting. You could also require every assignee or a quorum to approve. The **Service level** tab adds due dates, reminders and escalations.

**Condition:** Select the condition, click **Add branch**, name it `More than 5 days`, and set it to **Number of days**, **Greater than**, `5`. The step now has two outputs: **More than 5 days** and **Otherwise**.

![Configuring the condition](https://aspnetzero.com/Images/Blog/workflow-condition.png)

**Notification:** Give it the name `LeaveApproved`, the subject `Your leave request was approved` and a message such as `Your request {businessReference} for {workflowName} was approved.` On the **Recipients** tab, tick **The requester**.

**Connections:** Finally, drag from each step's output port to the input port of the next step:

| From | Output | To |
| --- | --- | --- |
| Start |  | Form |
| Form |  | Team lead approval |
| Team lead approval | Approved | Condition |
| Team lead approval | Rejected | Rejected |
| Team lead approval | Changes requested | Form |
| Condition | More than 5 days | HR approval |
| Condition | Otherwise | Notify the requester |
| HR approval | Approved | Notify the requester |
| HR approval | Rejected | Rejected |
| HR approval | Changes requested | Form |
| Notify the requester |  | Approved |

The **Auto layout** button can line up the diagram for you, and the **What this workflow does** panel describes the flow in plain language so you can check it as you go.

## Step 5: Validate, Simulate and Publish

Before anyone uses the workflow, make sure it behaves as intended.

Click **Validate**. It runs the same checks as publishing, and each problem names the step it belongs to, such as an approval without an assignee or an output that is not connected. When everything is fine, you see **No problems found. The workflow is ready to publish.**

Then open the **Simulation** tab. It runs the workflow without creating a request. Choose `alice` as the requester, set the decisions for each approval, enter `7` for **Number of days** and click **Run simulation**. The result shows the exact path and who each step would be assigned to.

![Simulating the workflow](https://aspnetzero.com/Images/Blog/workflow-simulation.png)

Run it again with `3` days and you will see that the HR approval is skipped.

Now click **Publish**. The workflow becomes **Active** as **v1** and appears in the **Request Catalog**.

## Step 6: Run the Workflow

### Alice requests leave

Alice logs in, goes to **Workflows > Start a Request** and clicks **Start** on the **Leave request** card.

![The Request Catalog](https://aspnetzero.com/Images/Blog/workflow-request-catalog.png)

She fills in the form for seven days of leave and clicks **Submit**. Each request gets a reference number and can be followed from **My Requests**.

![Filling in the leave request](https://aspnetzero.com/Images/Blog/workflow-request-form.png)

### Bob asks for a correction

Bob receives a notification and finds the task in his **Approval Inbox**, which also counts pending, overdue and due soon tasks.

![The Approval Inbox](https://aspnetzero.com/Images/Blog/workflow-approval-inbox.png)

He opens the request and notices that the end date is wrong. Rather than rejecting the request, he enters a reason and clicks **Request changes**.

![Deciding on a task](https://aspnetzero.com/Images/Blog/workflow-task-decision.png)

### Alice corrects the request

The request goes back to Alice with Bob's reason at the top of the page. She fixes the end date and clicks **Resubmit**.

![A request with changes requested](https://aspnetzero.com/Images/Blog/workflow-changes-requested.png)

### Bob and Carol approve

Bob approves the corrected request. Because 7 is greater than 5, the condition sends it to HR, and Carol approves it from her own inbox. The request closes as **Approved**, and Alice receives the "Your leave request was approved" notification.

![The approved request](https://aspnetzero.com/Images/Blog/workflow-request-approved.png)

The request's **Timeline** records every submission, decision and notification, together with the person and the reason. This gives you an audit trail without any extra work.

![The request timeline](https://aspnetzero.com/Images/Blog/workflow-timeline.png)

If Alice had requested only three days, the request would have been approved right after Bob's decision, and Carol would never have seen it.

## Changing the Workflow Later

Processes change, and the workflow can change with them. Open it in the designer, edit it and publish again to create a new version. **Requests that are already running continue on the version they started with**, so a change never disturbs requests in progress. If the host allows it, running requests can also be migrated to a newer version.

## Beyond Your First Workflow

A leave request only scratches the surface. Here are some of the other things the builder can do:

- **More flow control:** Run branches at the same time with **Parallel** and **Join**, hold a request with a **Timer**, or start another workflow with a **Subprocess**.
- **Holiday cover:** Approvers can hand their tasks to a colleague for a period of time with **Workflow Delegations**.
- **Monitoring:** Follow requests from **Workflow Instances**, **Workflow Operations** and **Workflow Audit**, and find out where your processes stall with **Process analytics**.

![Process analytics](https://aspnetzero.com/Images/Blog/workflow-analytics.png)

Hosts can also enable optional capabilities from **Administration > Settings > Workflows**:

- **Scheduled** and **Public form** triggers
- **Action** steps that call registered actions, webhooks and HTTP endpoints
- **Wait for event** steps that hold a request until an external system reports back
- Deciding from the **approval email**, or from **Microsoft Teams** and **Slack** cards
- **BPMN 2.0** import and **Elsa** JSON import and export
- **AI-assisted authoring** to draft workflows from a description

## Learn More

This post covers the main path. The documentation has every setting, and the tutorial walks through each click:

- [Create Your First Workflow](https://docs.aspnetzero.com/aspnet-core-angular/latest/Features-Workflows-Create-Your-First-Workflow): The full step-by-step tutorial.
- [Workflow Designer](https://docs.aspnetzero.com/aspnet-core-angular/latest/Features-Workflows-Designer): The form builder, every step type, triggers, validation, simulation and versions.
- [Requests and Approvals](https://docs.aspnetzero.com/aspnet-core-angular/latest/Features-Workflows-Requests-And-Approvals): Starting requests, deciding on tasks, requesting changes and delegating.
- [Workflow Administration](https://docs.aspnetzero.com/aspnet-core-angular/latest/Features-Workflows-Administration): Host and tenant settings, permissions and monitoring pages.

The workflow and approval builder is available in ASP.NET Zero v15.5. To see what else is new in this release, read [Introducing ASP.NET Zero v15.5](https://aspnetzero.com/blog/introducing-asp.net-zero-v15.5).

For questions, suggestions, or support, feel free to reach us at: 📩 **info@aspnetzero.com**

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