01No custom code
The flow
People pass work between each other. The BPMN diagram controls tasks and decisions; forms and language live in the process folder.
Example: a request is recorded, reviewed and approved.
Design processes
Start with the diagram. Program only when needed.
ProcessBlocks distinguishes four levels of process design. Levels 1 and 2 need no process-specific code: draw the flow in Camunda Modeler (the BPMN designer) and configure forms and module steps in the process folder.
The levels build on each other. A process may combine human work, existing modules and custom logic. For most, Level 2 is the right destination.
02No custom code
Reusable modules
A service task in the diagram names an existing capability. The worker serves it for any process that declares it. The step stays visible in the diagram and failure view.
Example: send a message or render and file a document.
03With business logic
Process-specific rules
When a decision needs computation, Lua lives in the version folder. The script runs within time and memory limits and can request external effects only through declared platform capabilities.
Example: calculate a business key or evaluate a complex condition.
04Compiled code
Specialized integrations
For work beyond reusable modules and Lua, a developer can write a process-specific Rust handler against the ProcessBlocks SDK. The worker subscribes to its declared tasks. No current example process needs this level.
Example: an unusual integration with an internal system.
Level 3, in practice
A small rule can do useful work.
An expense claim is €850; the configured approval limit is €500. A service task in the diagram runs a short Lua rule:
- 01
Read a value
The platform retrieves the declared approval limit. The rule reads it alongside the claim amount.
- 02
Make the decision
The rule compares the two values and decides whether another review is needed.
- 03
Request a module
If needed, it returns a request to a permitted notification module. The worker checks and performs that action after the rule returns.
- 04
Set a field
It returns a result field such as “extra review required”, which the process can show or use at its next BPMN decision.
External reads happen before the rule runs. The rule itself cannot call an API or send a message directly; its requested actions remain declared and visible.
An important distinction
“No programmer” still involves configuration.
You can design the BPMN flow visually. Forms, language and the permitted modules also belong in the process folder and need to be maintained. Levels 1 and 2 require no custom programming.
What the levels change
Responsibility grows with the need.
Moving up a level is a deliberate choice about more freedom and the review that comes with it.
Visible in the diagram
Levels 1 and 2 keep the important flow and the modules used legible to business users and operators.
Constrained code
Level 3 keeps custom logic in the process folder and limits what the script itself can do.
Targeted extension
Level 4 is reserved for needs that a diagram, generic modules and sandbox cannot reasonably cover.
Your process, your environment
Let’s talk about your first process.
We can show how a workflow becomes a versioned process folder, and which steps need no custom programming.
Get in touch