Choosing among open source BPM tools can feel like guesswork. Most are workflow engines built around standard notations, and the real differences are lineage, notation support and how much you must build yourself.
This page is part of our coverage of open source software.
| Item | Value |
|---|---|
| BPMN first published | 2004 |
| CMMN first published | 2014 |
| DMN first published | 2015 |
| Flowable forked from Activiti | 2017 |
| Open source BPM projects compared in depth | 4 (jBPM, Camunda, Activiti, Flowable) |
Figures come from Capital One’s 2022 open source BPM comparison. They can change, so check the source before you rely on them.
What a BPM tool actually does
A business process management tool lets you model a process, run it and watch it. In the open source world that usually means an engine that executes diagrams, plus a modeler and task screens.
Typical building blocks you will meet:
- A visual modeler for drawing the process.
- An execution engine that moves work between steps and people.
- Task lists, notifications and state tracking.
- Decision tables for if/then business rules.
The same comparison separates simple workflow, such as a to-do list with notifications and status, from complex workflow spanning many groups and teams. Knowing which of the two you have is the first filter, because many needs are met by a lighter tool than a full BPM engine.
A simple approval chain inside one team rarely needs a process engine. A claims or onboarding process that crosses departments, with audit needs and decisions, is where a BPM tool earns its place.
The three standard notations
Capital One’s write-up says, “There are three industry standard notations: BPMN, CMMN, and DMN.” Each covers a different job.
- BPMN models business processes and was first published in 2004.
- CMMN models case management, which is ad-hoc and unpredictable, and was first published in 2014.
- DMN models decisions, and followed a year later in 2015.
Because BPMN models are portable, a diagram built in one application can be used in another, provided the tooling added nothing proprietary.
That portability also helps teams work together. A business analyst familiar with BPMN can create a process and hand it to technical colleagues to implement in a BPM product.
CMMN suits investigative work, where the next step depends on what the person finds. DMN is the piece you reach for when a process needs if/then logic to make a decision. The source adds that, in the years after DMN appeared, a number of open source products built support for DMN along with CMMN.
The Java lineage: jBPM, Activiti and Flowable
Flowable’s own history says “the story of open source Java BPM really began with jBPM, continued with Activiti and then to Flowable.” jBPM 1.0 was released in 2003 and jBPM 2.0 joined JBoss in 2004.
jBPM 4.0 reached alpha in 2009 but never had a final release, because the team left to start Activiti. The next release, jBPM 5.0, took a different approach based on the Drools rules engine.
Flowable 6.0 was released in early 2017, as a fork off Activiti. Flowable’s history also says a fork was taken from Activiti to create Camunda, which at the time of that post was version 7 and still based on the 5th generation process engine.
Knowing this helps when you read older tutorials, since version numbers do not always map to the same generation. It also explains why the tools feel familiar to each other: they share ancestry and a Java foundation.
How the open source model differs between tools
Capital One compares each of the four projects on three dimensions:
- Open source model, meaning community versus enterprise editions.
- Capability set.
- Community activity.
The first matters most in practice. The source calls it “one of the most important aspects to understand as each open source BPM product has a different open source model,” and says you need to be clear on what is in the community edition versus the enterprise one.
Its findings, as of that 2022 write-up, illustrate how much the models vary:
- jBPM has “the simplest and most open model”: everything in the community version is in the enterprise version, and the difference is support from Red Hat.
- Camunda has a different model. Its Zeebe engine is source-available and its modeler is open source, while the operational modules are not open source but are free to use in QA.
- Activiti has a different model again from jBPM and Camunda.
The lesson is to read the licence and edition page of whichever tool you shortlist. “Open source” on a marketing page does not tell you which features you can run in production without paying.
What to compare before you pick one
Feature lists blur together, so compare on things you can test. Our guide on how to choose open source software covers the general checks.
- Notation support: does it run BPMN only, or also CMMN and DMN?
- Edition: confirm what the free edition includes on the project’s own site.
- Skills: these engines grew from a Java lineage, so check your team’s comfort.
- Maintenance: look at recent releases and community activity.
- Hosting: decide whether you will run it yourself or buy it as a service.
On hosting, the comparison notes that Camunda provides a SaaS offering while Alfresco Activiti provides a PaaS offering known as Alfresco Cloud. It also says Flowable has shown its engine running in a serverless approach, such as in an AWS Lambda.
If you plan to run it on your own servers, read about self-hosted workflow automation first. Capital One’s comparison is dated 2022, so verify current versions and editions before deciding.
A practical way to shortlist
Start with one real process, not a feature checklist. Pick something that crosses at least two teams, write it out as a BPMN diagram, and note where a decision or an exception appears.
Then try that same diagram in two candidate tools. Because BPMN is a shared notation, the diagram itself should carry over, and the time you spend will show you what is different: the modeler, the task screens, the way forms and decisions are attached, and how errors are reported.
Keep a short record of what you find:
- How long it took to get the diagram running end to end.
- Which features you needed that sat outside the free edition.
- Whether decisions could be kept in DMN tables rather than code.
- How easy it was to find answers from the community.
This small trial is cheaper than reading endless comparisons, and it surfaces the edition limits that matter to you. Treat any review, including the one cited here, as a starting point rather than a verdict, since projects change quickly.
Frequently asked questions
Are open source BPM tools free to use?
The core engines are free to download and run, but editions differ, so read each project’s licence page. Hosting and staff time still cost money.
Which tools are in the main comparison?
Capital One’s 2022 deep dive covers four projects: jBPM, Camunda, Activiti and Flowable.
Can I move a BPMN diagram between tools?
Often yes, since BPMN models are portable, unless the tooling added proprietary items on top of the standard.
What is DMN for?
DMN handles the if/then logic behind business decisions inside a process.
