For requirements collection and high-level stakeholder communication, product managers need to be able to describe how a consumer will interact with a system or product. This can include a description of the product’s users, how they interact with the product, and what it does.
In this guide, we’ll define what a use case is, describe the elements therein and what they are designed to do, and walk through how to build a use case step by step.
We’ll also look at some use case examples to show what they look like in practice.
If you’d like to write your own use case while following along with this article, here is a free use case template. To use the template, select File > Make a copy from the top menu bar.
A use case is an essential tool for documenting and designing software requirements. It describes how users interact with a system to accomplish a specific goal. If you’re new to writing use cases this comprehensive guide will walk you through each step of the process. Follow along to learn use case fundamentals best practices, helpful templates, and real examples.
In this article, we’ll cover:
- What is a use case and why is it useful?
- Steps for writing a use case
- Tips for writing excellent use cases
- Use case template and examples
Whether you’re a product manager, business analyst, or developer, having strong use case writing skills can improve your requirements gathering and technical design. Let’s get started!
What is a Use Case?
A use case outlines how a user interacts with a system to achieve a goal. It describes the user’s actions and the system’s responses in a step-by-step format. Use cases don’t specify technical details – instead, they capture the business purpose and requirements for a feature from the user’s perspective.
Well-written use cases are essential because they:
- Clearly document the intended functionality of a system
- Provide a structured way to define requirements
- Allow developers and stakeholders to align on what should be built
- Serve as a reference for testing to ensure requirements are met
Steps for Writing a Use Case
Follow these steps when writing a use case
1. Describe Your System
Start by briefly describing the system or product you are documenting use cases for. This gives readers essential context before diving into the specifics of each use case.
For example, you may write “The parking garage payment system allows customers to pay parking fees before exiting the garage.”
2. Identify the Actors
The actor is the person or external system that will interact with the system you are building. Common actors include:
- Customer
- User
- Manager
- Payment system
- Login system
For our parking garage example, the actor would be “Customer”.
3. Define Your Actors’ Goals
What does the actor want to achieve by using your system? Defining goals helps you identify the right use cases to document.
For our example, the Customer’s goal is “Pay parking garage fees.”
4. Create a Scenario
Writing a scenario outlines the expected interaction between the actor and the system. Describe each step the actor takes to achieve the goal.
Our example scenario could be:
- Customer drives up to payment kiosk and enters space number
- System looks up time parked in space
- System calculates parking fee based on time
- Customer selects payment method
- Customer pays parking fee
- System displays paid receipt
- Exit gate opens for Customer to exit
Number each step for clarity. Use simple, everyday language to keep the scenario easy to follow.
5. Consider Alternate Flows
After the main success scenario, identify any alternate flows that may occur. Common alternatives include:
- What happens if a step is done out of order?
- How are errors or unsuccessful transactions handled?
- Are there optional steps a user can take?
For our example, alternate flows may include:
- Customer forgets space number: Customer can search by license plate number
- Payment fails: System asks Customer to retry or use a different payment method
6. Repeat Steps 2-5 to Compile Your Use Cases
A well-documented system will have multiple use cases to cover all the different ways users interact with it. Make a list of all major goals and scenarios. Follow the steps above to create a use case for each one.
Prioritize use cases that describe the most important or frequently-used functionalities. If needed, you can create “subflows” with additional steps within a use case.
Now let’s look at some best practices for writing excellent use cases.
Tips for Writing Use Cases
Follow these tips when drafting use cases:
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Keep it simple – Avoid technical jargon. Use natural language.
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Focus on the user – Document what the actor needs, not system internals.
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Avoid implementation details – Don’t specify how the system works – just the end result.
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Be consistent – Use the same actor names and language across use cases.
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Number the steps – This makes the flow easy to follow at a glance.
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Validate frequently – Review use cases with stakeholders to ensure accuracy.
Use Case Template and Examples
Below is a use case template you can follow. We’ve also included examples for writing use cases for two common systems.
Use Case Template
Use Case Name: Name that summarizes goal
Actor: Person or system interacting with your system
Goal: What the actor wants to achieve
Preconditions: Any essential setup before the use case starts
Postconditions: How the system should be after use case ends
Main Success Scenario:
- Step 1
- Step 2
- Step 3
Alternate Flows:
- Alt Flow 1
- Alt Flow 2
Customer Order Use Case
Use Case Name: Place Online Order
Actor: Customer
Goal: Buy products online
Preconditions: Customer is registered and logged in
Postconditions: Order is placed in system
Main Success Scenario:
- Customer browses product catalog
- Customer adds desired products to cart
- Customer proceeds to checkout
- Customer enters shipping address
- Customer selects shipping option
- Customer enters payment info
- Customer confirms order
- System processes order
Alternate Flows:
- Customer needs to update billing address before confirming order
- Transaction fails, Customer tries new payment method
ATM Use Case
Use Case Name: Withdraw Cash
Actor: Bank Customer
Goal: Withdraw money from account at ATM
Preconditions: Customer has a bank account and ATM card
Postconditions: Cash is dispensed to Customer
Main Success Scenario:
- Customer inserts ATM card
- System prompts for PIN
- Customer enters PIN
- System presents account options
- Customer selects “Withdraw Cash”
- System prompts for withdrawal amount
- Customer enters amount
- System dispenses cash
- System prints receipt
- System returns ATM card
Alternate Flows:
- Invalid PIN entered
- Not enough cash in ATM to fulfill request
Following a use case template and looking at examples makes it easier to write effective use cases, even if you’re new to it. With these practical tips, you can master the skill and improve your requirements gathering process.
Who creates use cases?
Product management, product development, and product testing domains all use the use case methodology. Product managers and developers employ use cases in a similar manner: as a design tool to specify how the system will react to user activities. However, there are some key differences.
Product managers typically document user-focused use cases whereas developers document product-focused use cases. The user-focused use cases are primarily concerned with the user and their objectives. These are then passed to developers to guide decision-making during the product development process.
Product developers frequently add technical and design elements to provide crucial context. This set of improved use cases gives the development team the insight it needs to start designing, creating, and testing the product and its features.
Elements of a use case
Let’s break down the components of a typical use case and explain the purpose and objective of each.
Actors are the people or things that interact with your system. An actor could be an individual, a company, a team, or something else entirely. Anything that exists outside of a system and engages in some sort of interaction with it qualifies as an actor.
How to Write a Use Case
How do I write a use case?
Writing a use case sounds complex, but only requires understanding your system and its users. You can write a use case by following these six steps: 1. Describe your system Start by describing your system, or the product or service you and your team will build. Focus your description on what your system does for users.
What is an example of a use case?
This is a more granular goal. Some example use cases include: Use cases represent specific and concrete things that a user can do with the software system, and it captures all the ways that that user and system can interact.
How do you understand a use case?
To understand a use case, you need to identify the actors and the use cases involved in the system. An actor is an external entity that has a role in the interaction with the system. An actor can be a person, another system, or a time event.
What should be included in a use case?
Here are some basic components to include when writing a use case: System: This may include the site, the software, the app or the program you want to run the use case to assess. Including this information is especially important when writing use cases for multiple systems.
