Softwr

Automation Integration · head to head

Activiti vs Nebula

Activiti logo

Activiti

Automation Integration

Apache 2.0 BPMN engine under Hyland, from which Flowable and Camunda were forked

From
Free
Rated
-
Full reviewWebsite
Nebula logo

Nebula

Networking

Certificate based overlay network from Slack, with identity and firewall rules carried in the certificate

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Activiti the last stable release was 8.2.0 in January 2024, and while release candidate builds continue, a two-year gap between stable versions is a real risk signal for a production dependency.; Nebula the open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • They diverge on capability: Activiti covers BPMN 2.0 engine, Nebula covers Certificate carried identity.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Activiti and Nebula actually diverge.

Attributes where Activiti and Nebula differ
AttributeActivitiNebula
PlatformsLinux, Windows, Docker, KubernetesLinux, macOS, Windows, iOS, Android, FreeBSD
CategoryAutomation IntegrationNetworking

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Activiti

  • BPMN 2.0 engine
  • Activiti Cloud
  • Modeler
  • Java and REST APIs
  • Pluggable persistence
  • Identity integration

Only in Nebula

  • Certificate carried identity
  • Group based host firewall
  • Lighthouse discovery
  • Noise protocol encryption
  • Unsafe routes
  • Managed option

What people use each for

The jobs each tool is most often brought in to do.

Activiti

  • An Alfresco or Hyland content services deployment where Activiti is already the embedded workflow enginenot Nebula
  • A Java application that needs to embed a BPMN engine as a library under a permissive licencenot Nebula
  • An organisation that has ruled out Camunda 8 on licence grounds and needs an Apache 2.0 alternativenot Nebula
  • Document-centric approval workflows where the process engine sits inside the content management stack rather than beside itnot Nebula

Nebula

  • Flattening a network across several clouds and datacentres without VPC peering or route tablesnot Activiti
  • Very large fleets where a central policy service on the connection path is unacceptablenot Activiti
  • Environments that already run an internal certificate authority and want the network to use itnot Activiti
  • Replacing per host iptables rules with policy written against roles that follow the hostnot Activiti

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Activiti

  • The last stable release was 8.2.0 in January 2024, and while release candidate builds continue, a two-year gap between stable versions is a real risk signal for a production dependency.
  • Both Camunda and Flowable forked away and took large parts of the contributor base with them, so the community, tutorials and third-party tooling around Activiti are much thinner than around either fork.
  • Commercial support is only realistically available by buying Hyland Alfresco subscriptions, so there is no way to pay for Activiti support on its own.
  • Activiti Cloud imposes a distributed architecture of several Spring Boot services plus Keycloak, which is heavy for teams who simply wanted an embeddable engine.
  • Documentation is dated and partly split between old Alfresco sites and Hyland Connect, and the transition between Activiti 6, 7 and 8 architectures makes much of the older material actively misleading.

Nebula

  • The open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • Revoking a compromised host means distributing a blocklist entry to every other host and reloading them, which is a fleet wide operation rather than a click, and easy to get wrong under pressure.
  • Changing a host group membership means reissuing and redeploying its certificate, so policy changes are a deployment rather than a configuration edit.
  • There is no identity provider integration or single sign on in the open source version, so it maps well to servers and badly to a fleet of user laptops.
  • NAT traversal is best effort and hosts behind symmetric NAT need a relay configured deliberately, so connectivity failures show up as intermittent rather than immediate and are awkward to diagnose.

Pricing, plan by plan

Activiti

Free
  • ActivitiFree
    • Apache 2.0 licence
    • Embeddable Java library or Activiti Cloud services
    • No usage limits

Nebula

Free
  • NebulaFree
    • Full functionality under the MIT licence
    • No host limit
    • You operate the certificate authority and lighthouses
  • Defined Networking$undefined/month
    • Hosted control plane and enrolment
    • Managed certificate lifecycle and revocation
    • Policy and DNS interface

Which should you pick?

Choose Activiti if

  • You need bpmn 2.0 engine.
  • You want to start without paying.
  • You work on Linux, Windows, Docker, Kubernetes.
  • You also want activiti cloud.
Activiti review

Choose Nebula if

  • You need certificate carried identity.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, iOS, Android, FreeBSD.
  • You also want group based host firewall.
Nebula review

Questions people ask

Is Activiti or Nebula better?
Neither clearly leads. Activiti starts at Free and Nebula at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Activiti or Nebula?
Activiti starts at Free and Nebula at Free.
Does Activiti or Nebula run on more platforms?
Activiti runs on Linux, Windows, Docker, Kubernetes. Nebula runs on Linux, macOS, Windows, iOS, Android, FreeBSD.
Can I use Activiti for free?
Both have a free tier, so you can try either at no cost before committing.
What is Activiti best used for?
Activiti is most often used for an alfresco or hyland content services deployment where activiti is already the embedded workflow engine, a java application that needs to embed a bpmn engine as a library under a permissive licence, an organisation that has ruled out camunda 8 on licence grounds and needs an apache 2.0 alternative, document-centric approval workflows where the process engine sits inside the content management stack rather than beside it. Of those, an alfresco or hyland content services deployment where activiti is already the embedded workflow engine and a java application that needs to embed a bpmn engine as a library under a permissive licence are not what Nebula is typically brought in for.
What can Activiti do that Nebula cannot?
Activiti covers BPMN 2.0 engine, Activiti Cloud, Modeler, Java and REST APIs. Nebula covers Certificate carried identity, Group based host firewall, Lighthouse discovery, Noise protocol encryption.

Answered from the vendors’ own pages

Activiti: Is Activiti still maintained?

Yes, Hyland continues to publish builds, but the last stable release was 8.2.0 in January 2024.

Nebula: Does it use WireGuard?

No. Nebula predates the common WireGuard mesh tools and uses the Noise protocol framework with its own certificate format.

Activiti: What is its relationship to Camunda and Flowable?

Both are forks of Activiti: Camunda in 2013 and Flowable in 2016, when core developers left Alfresco.

Nebula: Can I run it without Defined Networking?

Yes, entirely. Defined Networking sells the control plane conveniences, not the network itself.

Activiti: What licence is it?

Apache 2.0, which distinguishes it from Camunda 8’s source-available licence.

Nebula: How do I revoke a host?

Add its certificate fingerprint to the blocklist in the configuration of the other hosts and reload them. There is no online revocation check.

Activiti: Should I choose Activiti for a new project?

Only if the Apache licence or an existing Alfresco deployment is decisive. Flowable and Camunda have far larger ecosystems.

Nebula: Is it a good fit for laptops?

Less so than the identity provider based tools. There is no single sign on, so every laptop needs a certificate issued and renewed by whatever process you build.

Share

Related pages

More on Activiti

More on Nebula

Keep looking

Other head to heads