Using Swim Lane Diagrams to Improve Software Development

    Swim lane diagrams are process flowcharts that identify who does what, and when. Comprised of a series of horizontal or vertical paths, likened to swimming lanes in a pool, these diagrams allow for the mapping of simultaneous processes, activities, and objectives.

    What is a Swim Lane Diagram?

    Swim lane diagrams are a visual answer to the question, “…and then?” To begin, consider the process, interaction, or workflow that your team needs to better understand or accommodate.

    Begin the creation of your swim lane diagram by identifying your goals and the perspective required. Are you looking to show a high-level view of the interaction between departments in your organization, or a detailed step-by-step progression of the steps needed to complete specific tasks? Don’t discount that your swim lane diagrams may have several versions depending on the intended audience.

    Though participants are often particular users, they can also be roles (salesperson, developer, HR director, etc.) or even ancillary systems; in the case of a swim lane that may identify the relationship and communication between external providers or consumers of your organization’s data, or network architecture interactions such as web servers connecting to database and email servers. 

    Also read: Using Prototyping to Accelerate Software Development

    Anatomy Of A Swim Lane Diagram

    Swim lane diagrams take advantage of the same shapes and symbols found in flowcharting.


    • Oval – Represents the start and end of a process or flowchart. Every swim lane diagram should have at least two.
    • Rectangle – General considered to be the go-to symbol in a swim lane diagram. Rectangles capture the process steps, tasks, or actions.
    • Arrow – Shows directional flow along the swim lane diagram’s path. Consider labeling these connections to avoid any confusion, particularly with complex diagrams where the arrow heads can be very small and difficult to discern.
    • Diamond – Indicates when a decision is required to move forward. Diamonds communicate that there is a question, the answer to which will determine the next step down the path.


    • Document Symbols – Can be singular or multiple, frequently referring to points where documentation must be updated or when the review of external paperwork is recommended or required.
    • Data Symbols – Includes images to represent databases and various types of data storage. These can be handy when skimming complex swim lane diagrams for instances when databases are being accessed or data backups are being created.
    • Loop and Delay Symbols – Identify repeated process steps easily or define waiting periods that are part of the flow. These are frequently used for software applications that generate invoices or statements. They may also indicate when calculations or updates are performed at-a-later-time (such as overnight).
    • Miscellaneous – For complex swim lane diagrams, it can be helpful to utilize the lesser-known symbols for input/output, manual operation (requiring user input to continue), or display (information being shown to a user). Other symbols indicate areas where one swim lane diagram merges or connects to another, detailing flow to other processes.

    Swim Lane Diagram Example

    Consider the following swim lane diagram example detailing the service desk workflow for an organization.

    picture of a swim lane diagram.

    Notice that there are three lanes, one for each of: User, CSR, and Tech Support. These lanes contain a series of actions, decisions, and activities that are being completed in parallel to each other. It is important to understand that there are several areas where tasks align across all the lanes—these are the areas where progression cannot occur until all the requisite items are addressed.

    This swim lane diagram could later evolve to include additional considerations and interactions that may be required if the solution requires the engagement of a development team, needs a customer service representative or salesperson, or to add more granular task details such as regression testing or updating knowledge base documentation. 

    Risk Identification and Process Improvement

    One of the biggest benefits of a swim lane diagram is to identify missed steps, eliminate duplication of efforts or task redundancy, and to predict bottlenecks or security threats.

    Identify missed steps

    Did you assume that your service desk staff were always updating your knowledge base when issues get resolved? Are salespeople supposed to begin order entry for customers by first confirming current address and telephone number details? Are you sure that every requisite step is being completed so your database backups take place regularly?

    Swim lane diagrams can be a fantastic source of truth, serving as a reference to be sure the things you think are happening actually are.

    Eliminate duplication of efforts and task redundancy

    How many employees start their day by checking the same voicemails? Are multiple members on the same team performing overlapping activities that could be better handled with categorization and delegation?

    Swim lane diagrams help to identify the places where you can streamline mundane or repetitive tasks, freeing up resources to complete more valuable and rewarding work.

    Predict domino-style consequences, and understand security threats

    It can be difficult to keep track of which teams or how many of your users are accessing or updating sensitive data. Swim lane diagrams provide a comprehensive and visual way to recall all of the roles, responsibilities, and access requirements, for the users of your applications. They let you know, with confidence and authority, whether a salesperson making an update to a customer record will cause unintended consequences for your financial team as they run monthly invoices or statements. 

    Swim lane diagrams can also help mitigate risks when upgrading existing software applications or procuring new tools. Understand at a glance which users or systems are current consumers of the data or functionality being offered by the new or existing systems, and ensure that they can be part of the planning and testing activities for those projects.

    Swim lane diagrams are like dictionaries, providing descriptions and definitions for organization-specific details.

    Taking Swim Lane Diagrams a Step Further

    Swim lane diagrams offer clear benefits to organizations, helping to understand, improve, and support business processes. These passive benefits have value, but consider how you might also employ swim lane diagrams to support organizational changes and evolution.

    Change management

    If the purpose of change management is to mitigate risks associated with updates to software applications and business processes, it is critical that you know exactly which users need to be notified, updated, engaged, or even re-trained. Understanding how ancillary systems integrate with one another can help tremendously when trying to determine the impact of any and all changes. Swim lane diagrams can protect your service level agreements from risks by displaying both obvious and lesser known users of functionality and consumers of data.

    Human resources management

    Swim lane diagrams have tremendous potential to assist human resources management activities. Understand what will happen when a staff member is reassigned to a different department, and update their security credentials and access requirements accurately. If your payroll supervisor is away on vacation or off on a maternity or sick leave, know the logical team members to cover their responsibilities by identifying who performs similar or parallel tasks. Organizations can also use swim lane diagrams to more easily onboard new employees, identifying where accounts need to be created and access granted, but also to see which systems they may require training for. The same works in reverse, as an employee leaves the organization.

    Infrastructure management

    As the sophistication of IT infrastructures evolve, so do our dependencies on network resources and third-party services. Swim lane diagrams make it easier to manage these connections by providing the understandings needed to streamline demands for bandwidth, optimize frequent queries against large databases, or even understand how changes to your system may affect data being consumed or provided by outside agencies.

    Swim Lane Diagrams as a Development Tool

    Want to improve your existing software? Use swim lane diagrams to walk development teams through the workflows and business processes currently in place. Use them to supplement business requirements by walking developers through how the system needs to work—particularly when there are tasks that have specific complexities like the need for review and revision.

    Swim lane diagrams can also be a powerful visualization tool that can be used to demonstrate and rationalize the need for and the value of a new software application. Show the current state and compare it to the future, more streamlined and simplified state. Demonstrate where security will be enhanced, or infrastructure better utilized.

    For software versions of this type of tool, you can check out LucidChart, Creately, WonderShare, Canva, and Visio.

    Read next: Using Journey Maps to Understand Your Software Users

    Jillian Koskie
    Jillian Koskie
    Jillian Koskie is an experienced software developer, writer, business analyst, and usability design expert. With over 24 years in these roles, Jillian has enjoyed applying her considerable skill-set to assist clients and users across a wide variety of sectors including: legal, health, and financial services. Combining these professional opportunities with a love of technology, Jillian is pleased to act as a trusted advisor, contribute articles, voice opinions, and offer advice to numerous organizations, news outlets, websites, and publications.

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