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Automation Integration · head to head

Flowable vs Letta

Flowable logo

Flowable

Automation Integration

Apache 2.0 BPMN, CMMN and DMN engine from the team that originally built Activiti

From
Free
Rated
-
Full reviewWebsite
Letta logo

Letta

Automation Integration

Machines that learn

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Flowable the open source engine is genuinely usable but ships without the modelling studio, work application and admin console, so an open source deployment means building your own user interfaces before anyone can use it.; Letta free tier limited to 3 stateful agents
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Flowable and Letta actually diverge.

Attributes where Flowable and Letta differ
AttributeFlowableLetta
Pricing modelquotefreemium
PlatformsLinux, Windows, Docker, Kubernetes, CloudWeb

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Automation Integration).

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 Flowable

  • BPMN 2.0 engine
  • CMMN case management
  • DMN decision tables
  • Spring Boot integration
  • Modelling studio
  • Task and case application
  • REST APIs
  • History and audit

Only in Letta

Nothing recorded that Flowable does not also cover.

What people use each for

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

Flowable

  • An insurer automating claims handling where each case follows a different path and BPMN alone cannot express itnot Letta
  • A bank embedding process orchestration inside an existing Spring Boot estate rather than buying a separate platformnot Letta
  • A team leaving Activiti or jBPM that wants the same API family with active commercial maintenancenot Letta
  • A regulated organisation needing complete process history and decision table audit trails for supervisorsnot Letta

Letta

  • Building agents with memory for continuous learningnot Flowable
  • Enabling reflection during idle periods via sleep-computenot Flowable
  • Managing agent context and extracting learningsnot Flowable

Where each one falls short

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

Flowable

  • The open source engine is genuinely usable but ships without the modelling studio, work application and admin console, so an open source deployment means building your own user interfaces before anyone can use it.
  • It expects Java engineering capacity; teams looking for a business-user low-code automation tool will find the modelling and deployment cycle far too technical.
  • Enterprise pricing is not published and is quoted per deployment, leaving buyers without a benchmark against Camunda or IBM alternatives.
  • The Activiti fork left three engines with related APIs and overlapping documentation in circulation, and search results routinely return advice for the wrong one.
  • Flowable AG is a small Swiss company relative to its competitors, so the partner network, training market and pool of engineers with production experience are all limited outside Europe.

Letta

  • Free tier limited to 3 stateful agents
  • Pro tier capped at 20 stateful agents
  • API Plan usage charges apply beyond base tier

Pricing, plan by plan

Flowable

Free
  • Flowable Open SourceFree
    • Apache 2.0 licensed BPMN, CMMN and DMN engines
    • Embeddable Java library or standalone apps
    • No modelling studio or enterprise applications
  • Flowable Enterprise$undefined/year
    • Modelling studio, work application and admin console
    • Connectors, forms and advanced identity management
    • Support with SLA and version maintenance

Letta

Free
  • FreeFree
    • Limited agents
    • Limited Letta Auto usage
    • Bring your own API keys
  • Pro$20/month
    • Weekly and monthly Letta Auto quota
    • Pay-as-you-go overage
    • Up to 20 stateful agents
  • API Plan$20/month
    • Unlimited agents
    • $0.10/active agent/month
    • $0.00015/second for tool execution
  • Teams Pro$20/month
    • Per seat pricing
    • Add teammates
    • Letta Auto quota

Which should you pick?

Choose Flowable if

  • You need bpmn 2.0 engine.
  • You want to start without paying.
  • You work on Linux, Windows, Docker, Kubernetes, Cloud.
  • You also want cmmn case management.
Flowable review

Choose Letta if

  • You want to start without paying.
Letta review

Questions people ask

Is Flowable or Letta better?
Neither clearly leads. Flowable starts at Free and Letta at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Flowable or Letta?
Flowable starts at Free and Letta at Free.
Does Flowable or Letta run on more platforms?
Flowable runs on Linux, Windows, Docker, Kubernetes, Cloud. Letta runs on Web.
Can I use Flowable for free?
Both have a free tier, so you can try either at no cost before committing.
What is Flowable best used for?
Flowable is most often used for an insurer automating claims handling where each case follows a different path and bpmn alone cannot express it, a bank embedding process orchestration inside an existing spring boot estate rather than buying a separate platform, a team leaving activiti or jbpm that wants the same api family with active commercial maintenance, a regulated organisation needing complete process history and decision table audit trails for supervisors. Of those, an insurer automating claims handling where each case follows a different path and bpmn alone cannot express it and a bank embedding process orchestration inside an existing spring boot estate rather than buying a separate platform are not what Letta is typically brought in for.
What can Flowable do that Letta cannot?
Flowable covers BPMN 2.0 engine, CMMN case management, DMN decision tables, Spring Boot integration.

Answered from the vendors’ own pages

Flowable: Is Flowable open source?

Yes, the BPMN, CMMN and DMN engines are Apache 2.0. The modelling studio and enterprise applications are commercial.

Letta: How much does Letta cost?

Letta offers a free tier, then Pro plan at $20/month with up to 20 stateful agents, API Plan at $20/month base plus usage charges ($0.10/active agent/month, $0.00015/second for tool execution), and Teams Pro at $20/seat/month.

Source
Flowable: How does it relate to Activiti and jBPM?

The same core developers built jBPM, then Activiti, then forked Activiti in 2016 to create Flowable.

Letta: How many agents can I create on the free plan?

The free tier is limited to 3 stateful agents. Pro plan allows up to 20 stateful agents, while API Plan offers unlimited agents.

Source
Flowable: What does Flowable Enterprise cost?

Nothing is published. It is quoted per deployment by the vendor.

Letta: Does Letta charge for tool execution?

On the API Plan, Letta charges $0.00015 per second for tool execution. The Pro and Teams Pro plans include execution in their monthly fee.

Source
Flowable: Why choose it over Camunda?

CMMN case management is a first-class engine, which matters when work is exception-driven rather than a fixed sequence.

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