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Process Modelling Reference

Guide to BPMN Notation

BPMN (Business Process Model and Notation) is the international standard for process modelling — used by business analysts, process designers, and automation developers worldwide. This guide covers the core elements you need to read and create BPMN diagrams for automation projects.

Core Elements

The Building Blocks of BPMN

BPMN has over 100 notation elements — but 80% of process diagrams use fewer than 15 of them. Every BPMN diagram is built from four categories: Events (what starts, pauses, or ends a process), Activities (the work that gets done), Gateways (decision and branching points), and Flows (the connections between elements).

Category Elements Purpose
Events Start Event, Intermediate Event, End Event Mark where a process begins, pauses, or terminates. Shown as circles — thin border for start, double border for intermediate, thick border for end.
Activities Manual Task, Automated Task, Sub-Process Represent the work being performed — by a person, a system, or a group of steps collapsed into a single element.
Gateways Exclusive (XOR), Parallel (AND), Inclusive (OR) Control how the process branches and merges. Shown as diamonds — the symbol inside identifies the gateway type.
Flows Sequence Flow, Message Flow Connect elements in order. Sequence flows show process order within a pool; message flows show communication between pools.

Events

Start Events

Event Symbol Description When to Use
None Start Event
The process starts without a specific trigger. Used for manually initiated or unspecified triggers. When the trigger is either manual or irrelevant to the process design.
Message Start Event
✉
 The process starts when a message is received from another process or participant — an email, API call, or system notification. KYC request received from onboarding portal; payment instruction received from client system; document submitted via customer portal.
Timer Start Event
⏳
 The process starts at a specific time, on a recurring schedule, or after a defined interval. Daily end-of-day reconciliation; monthly regulatory report generation; nightly batch processing runs.

Intermediate Events

Event Symbol Description When to Use
Message Intermediate Event
✉
 The process pauses and waits for a message to arrive before continuing. The process does not time out — it simply waits. Waiting for client to submit missing documents; waiting for counterparty confirmation; waiting for external system callback.
Timer Intermediate Event
⏳
 The process pauses for a defined duration or until a specific date/time before continuing. Acts as a scheduled wait within the flow. SLA countdown (process must resume within 4 hours); cooling-off period before sending a follow-up; daily cut-off wait before batch submission.

End Events

Event Symbol Description When to Use
None End Event
The process path ends without sending a signal or message. Standard termination of a flow path. Most process paths — approved, rejected, completed. Use when no outbound message or notification is needed.
Message End Event
✉
 The process ends by sending a message to another participant or system. The filled envelope indicates an outbound message. Sending approval notification to client; triggering downstream system at process completion; notifying a counterparty of a decision.

Activities

Tasks and Sub-Processes

Activity Symbol Description When to Use
Manual Task
✍ Manual
 A step performed by a human using their own judgement, without system assistance. Shown with a hand/pencil icon top-left. Document review that requires expert judgement; exception resolution; client call; physical action. Use when automation cannot or should not replace the human decision.
Automated Task
⚙ Auto Task
 A step executed entirely by a system, script, or automation engine without human intervention. Shown with a gear icon top-left. API call to core banking; automated sanctions screening; data extraction via IDP; RPA execution; rule-based calculation. The default task type for any step that runs without a person.
Sub-Process
Sub-Process+
 A collapsed set of activities that form their own internal process. The + symbol indicates the sub-process can be expanded. Contains its own start and end events. When a step is complex enough to deserve its own diagram — typically 5 or more internal steps. Common in banking for KYC verification, credit assessment, or multi-step document processing.

Gateways

Exclusive, Parallel and Inclusive

Gateway Symbol Description When to Use Banking Example
Exclusive Gateway (XOR)
×
 Exactly one outgoing path is taken. Each path has a condition; only the first true condition fires. All conditions must be mutually exclusive. Any decision with a single correct path — yes/no, approved/rejected, amount above/below threshold. The most common gateway type. Amount > €50,000 → Level 2 approval; Amount ≤ €50,000 → Level 1 approval. Only one path is ever taken.
Parallel Gateway (AND)
+
 All outgoing paths are taken simultaneously. When used as a join, the process waits for all incoming paths to complete before continuing. When multiple independent steps must all happen — and all must complete — before the process continues. No conditions are evaluated. KYC screening: AML check, sanctions screening, and PEP check all run simultaneously. Process only continues when all three are complete.
Inclusive Gateway (OR)
○
 One or more outgoing paths are taken based on conditions. Multiple paths can be active at the same time. When used as a join, waits for all active paths. When different combinations of paths apply depending on data — and more than one can be true simultaneously. Less common; use XOR if only one path can ever apply. Client risk profile: high net worth triggers private banking review; non-resident triggers additional compliance check; both can apply simultaneously to the same client.
Choosing the right gateway

Default to the Exclusive Gateway. Use Parallel only when all paths must run and all must complete. Use Inclusive only when multiple conditions can be true at once and different combinations of paths may apply. In most banking processes, 90% of gateways are Exclusive.

Flows

Sequence Flow and Message Flow

Flow Symbol Description When to Use
Sequence Flow
————▶
 Connects elements within the same pool in execution order. Solid line with filled arrowhead. Shows the direction the process flows. Connecting every element within your process — from start to end, including all tasks, gateways, and events in sequence. This is the default connection type.
Message Flow
○ - - - ▶
 Shows communication between two separate pools — different organizations, systems, or participants. Dashed line with open circle at source. Cannot be used within a single pool. Bank sending a notification to a client; client submitting a document to the bank; bank communicating with a regulator or counterparty. Always crosses a pool boundary.

BPMN in Practice
Common Process Patterns in BPMN

Document Validation Pattern

  • Start Event: Document received
  • Automated Task: Auto-classify document (IDP)
  • XOR Gateway: Valid / Invalid / Missing
  • Intermediate Event: Request resubmission (if missing)
  • User Task: Manual review (if invalid)
  • XOR Gateway: Valid / Rejected
  • End Events: Document validated / Rejected
Document validation workflow in BPMN notation

Multi-Level Approval Pattern

  • Start Event: Request submitted
  • XOR Gateway: Amount threshold check
  • User Task: Level 1 approval (low amount)
  • XOR Gateway: Approved / Rejected / Escalate
  • User Task: Level 2 approval (high amount or escalated)
  • End Events: Approved / Rejected
Multilevel approval workflow in BPMN notation

Exception Handling Pattern

  • Start Event: Process triggered
  • Automated Task: System executes process step
  • Boundary Error Event: Attached to automated task — fires on failure
  • User Task: Manual exception handling
  • XOR Gateway: Resolved / Escalated
  • Timer Intermediate Event: SLA countdown on main path
  • End Events: Resolved / Escalated
Exception handling workflow in BPMN notation

Best Practices
BPMN Modelling Standards for Automation Projects

Do

  • Name every task with verb + object (e.g., “Validate KYC document”)
  • Ensure every gateway has a label on each outgoing path
  • Include a default path on every exclusive gateway
  • Model the exception path alongside the happy path
  • Use pools to separate internal and external participants
  • Keep sub-processes for steps with 5+ internal activities
Don’t

  • Use BPMN for organizational charts or data models
  • Leave sequence flows without a clear direction
  • Create a gateway with only one outgoing path
  • Model implementation details inside the process diagram
  • Mix As-Is and To-Be process in the same diagram
  • Use different notation conventions within the same project