BPMN 2.0 Fundamentals

The Building Blocks of BPMN 2.0

Every BPMN 2.0 diagram is constructed from a small set of core elements. Once you understand these building blocks, you can read any BPMN diagram and create your own. Think of them as the alphabet of process modelling — master these elements and you can express any business process, no matter how complex.

The four fundamental categories are: Events (things that happen), Activities (work that is performed), Gateways (decision and branching points), and Connecting Objects (arrows that link everything together). We will examine each in detail, with banking examples throughout.

Events: Things That Happen

Events represent something that occurs during a process. They are always drawn as circles, and their border style tells you the type:

• Start Event — a thin single-bordered circle. Every process begins with a Start Event. It represents the trigger that kicks off the process. In banking, this might be "Customer submits account opening application" or "SWIFT payment message received."
• End Event — a thick bold-bordered circle. Every process path must terminate with an End Event. Examples: "Account opened successfully" or "Payment rejected and returned to sender."
• Intermediate Event — a double-bordered circle. These occur between the start and end of a process. They can represent things like receiving a message mid-process ("Document received from customer"), a timer ("Wait 48 hours for client response"), or an escalation trigger.

Each event type can carry an icon inside the circle to indicate its specific trigger or result. A clock icon indicates a timer event. An envelope indicates a message event. A lightning bolt indicates an error event. You do not need to memorise every icon right away — the important thing is to recognise the three border styles and understand that the icon specifies the trigger type.

Activities: Work That Is Performed

Activities represent the actual work done within a process. They are always drawn as rounded rectangles. BPMN distinguishes between two main types:

• Task — a single unit of work that is not broken down further in the current diagram. Examples: "Verify customer identity," "Run sanctions screening," "Post settlement entry."
• Subprocess — a compound activity that contains its own internal process. A subprocess is shown as a rounded rectangle with a small "+" marker at the bottom centre, indicating that the detail is collapsed and can be expanded. We will cover subprocesses in depth in Module 4.

Tasks can also carry type markers to indicate how the work is performed:

• User Task (person icon) — performed by a human using a system. Example: "Review KYC documentation in the case management platform."
• Service Task (gear icon) — performed automatically by a system or application. Example: "Automated sanctions screening against PEP lists."
• Manual Task (hand icon) — performed by a human without system assistance. Example: "Physically verify original identity documents at the branch."
• Script Task (scroll icon) — executed by a business rules engine or script. Example: "Calculate customer risk score based on rule matrix."

In banking process mapping, the distinction between user tasks and service tasks is particularly important because it makes clear which steps are automated (straight-through processing) and which require human intervention — a critical distinction for operational efficiency analysis and automation planning.

Gateways: Decision and Branching Points

Gateways control how the process flow splits and merges. They are always drawn as diamonds. The marker inside the diamond tells you the gateway type:

Exclusive Gateway (XOR) — marked with an "X" or left empty. The flow follows exactly one outgoing path based on a condition. This is the most common gateway in banking processes. Example: after running a sanctions screening, the process might branch to "Match found — escalate to compliance" or "No match — proceed with onboarding." Only one path is taken.

Parallel Gateway (AND) — marked with a "+" sign. All outgoing paths are activated simultaneously. This is used when multiple tasks must happen in parallel. Example: during account opening, the bank might simultaneously initiate "Order debit card," "Set up online banking," and "Send welcome pack." All three happen at the same time, and the process waits for all of them to complete before continuing.

Inclusive Gateway (OR) — marked with a circle (O) inside the diamond. One or more outgoing paths can be activated based on conditions. Example: depending on the customer's risk rating, the bank might need to perform "Enhanced due diligence" and/or "Source of wealth verification" and/or "Senior management approval." Any combination is possible.

A critical rule to remember: every splitting gateway should have a corresponding merging gateway. If you split the flow into three parallel paths, you need a merging parallel gateway to synchronise them before the process continues. Failing to do this is one of the most common errors in BPMN modelling.

Connecting Objects: Linking Elements Together

Three types of connectors link the elements in a BPMN diagram:

• Sequence Flow — a solid arrow with a filled arrowhead. This shows the order in which activities are performed within a single process (within a single pool). The vast majority of arrows in your diagram will be sequence flows.
• Message Flow — a dashed arrow with an open (unfilled) circle at the source and an open arrowhead at the target. This shows communication between two separate participants (between pools). Example: the bank sends an "Account verification request" to an external identity verification provider. That communication crosses organisational boundaries and is shown as a message flow.
• Association — a dotted line connecting a data object or annotation to an activity. Example: linking a "Customer application form" data object to the "Review application" task to show which document is used.

Understanding the distinction between sequence flows and message flows is essential. Sequence flows can never cross pool boundaries. If you need to show communication between two organisations or two major systems, you must use message flows.

Data Objects and Annotations

Two additional elements help make your diagrams more informative:

• Data Objects — shown as a page icon with a folded corner. They represent the information or documents used and produced by activities. Examples: "KYC file," "Payment instruction," "Risk assessment report." Data objects do not affect the process flow — they are informational.
• Text Annotations — shown as an open bracket with free text, connected to elements via associations. Use annotations to add context that does not fit neatly into task labels. Example: "Regulatory requirement: 4-eye check mandatory for transactions above EUR 100,000."

Banking Example: Customer Account Opening

Let us put all these elements together by mapping a simplified customer account opening process:

1. Start Event (thin circle): "Customer submits application online"
2. User Task (rounded rectangle, person icon): "Review application completeness"
3. Exclusive Gateway (diamond, X): "Application complete?"
   • No path: User Task: "Request missing documents from customer" followed by an Intermediate Timer Event (double circle, clock): "Wait 5 business days" followed by a loop back to the review task
   • Yes path: continues below
4. Parallel Gateway (diamond, +): Split into simultaneous activities:
   • Service Task (rounded rectangle, gear): "Run automated sanctions screening"
   • Service Task: "Verify identity via external provider"
   • User Task: "Assess customer risk rating"
5. Parallel Gateway (diamond, +): Merge — wait for all three to complete
6. Exclusive Gateway (diamond, X): "Risk rating acceptable?"
   • No path: User Task: "Escalate to senior compliance" leading to End Event (thick circle): "Application declined"
   • Yes path: Service Task: "Create account in core banking system"
7. End Event (thick circle): "Account opened — welcome pack sent"

This single example uses start and end events, intermediate events, user and service tasks, exclusive and parallel gateways, and sequence flows. It is a complete BPMN process map, and every element in it has a precise, standardised meaning.

In the next module, we will learn how to represent who performs each step by introducing pools, swimlanes, and message flows — essential for mapping the cross-departmental handoffs that define banking operations.