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OpenHAB vs Windmill

OpenHAB logo

OpenHAB

Smart Home

Open source automation software for your home

From
Free
Rated
-
Full reviewWebsite
Windmill logo

Windmill

Automation Integration

Open-source developer platform for building scripts, workflows, and internal apps

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: OpenHAB requires a 64-bit Java 21 JVM to be installed and maintained separately; Windmill free self-hosted tier caps SSO users at 10 and workspaces at 3, requiring Enterprise for larger teams.
  • They diverge on capability: OpenHAB covers Vendor Agnostic, Windmill covers Script-to-workflow engine.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which OpenHAB and Windmill actually diverge.

Attributes where OpenHAB and Windmill differ
AttributeOpenHABWindmill
PlatformsLinux, Windows, MacOS, Docker, Raspberry Piweb, api, linux, windows, mac
CategorySmart HomeAutomation Integration
Founded2010Unknown

Identical on both: starting price (Free), pricing model (open-source), 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 OpenHAB

  • Vendor Agnostic
  • Rule Engine
  • 200+ Bindings
  • Local Processing
  • Z-Wave
  • Zigbee
  • MQTT
  • REST API

Only in Windmill

  • Script-to-workflow engine
  • Auto-generated UIs
  • Self-hosted deployment
  • Git sync
  • SSO support
  • Audit logs

What people use each for

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

OpenHAB

  • Self-hosted vendor neutral home automation hubnot Windmill
  • Bridging smart home devices from different manufacturers under one set of rulesnot Windmill

Windmill

  • Turning ad-hoc scripts into scheduled jobs and APIsnot OpenHAB
  • Building internal tools from existing Python/TypeScript codenot OpenHAB
  • Self-hosted automation for engineering teamsnot OpenHAB
  • Orchestrating multi-language workflowsnot OpenHAB

Where each one falls short

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

OpenHAB

  • Requires a 64-bit Java 21 JVM to be installed and maintained separately
  • Oracle Java is explicitly not recommended by the project because of potential licensing restrictions
  • The recommended hardware is a dedicated Raspberry Pi 4 or newer rather than shared hardware
  • Some version upgrades require additional manual steps run through a separate upgrade tool

Windmill

  • Free self-hosted tier caps SSO users at 10 and workspaces at 3, requiring Enterprise for larger teams.
  • Compute unit and seat-based pricing (developer vs. operator seats, worker compute units) adds pricing complexity beyond a flat monthly fee.
  • Email triggers are capped at 100/day on the free tier, limiting event-driven use cases without upgrading.
  • Smaller ecosystem of pre-built integrations compared to more established automation tools like n8n.

Pricing, plan by plan

OpenHAB

Free
  • Community EditionFree
    • Unlimited devices
    • 200+ bindings
    • Local control

Windmill

Free
  • Free / Open-sourceFree
    • Unlimited executions
    • Self-hosted deployment
    • Max 10 users with SSO
  • Enterprise$120/month
    • Unlimited executions and workspaces
    • Uncapped SSO seats
    • 24/7 priority support (3-hour response)

Which should you pick?

Choose OpenHAB if

  • You need vendor agnostic.
  • You want to start without paying.
  • You work on Linux, Windows, MacOS, Docker, Raspberry Pi.
  • You also want rule engine.
OpenHAB review

Choose Windmill if

  • You need script-to-workflow engine.
  • You want to start without paying.
  • You work on web, api, linux, windows, mac.
  • You also want auto-generated uis.
Windmill review

Questions people ask

Is OpenHAB or Windmill better?
Neither clearly leads. OpenHAB starts at Free and Windmill at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, OpenHAB or Windmill?
OpenHAB starts at Free and Windmill at Free.
Does OpenHAB or Windmill run on more platforms?
OpenHAB runs on Linux, Windows, MacOS, Docker, Raspberry Pi. Windmill runs on web, api, linux, windows, mac.
Can I use OpenHAB for free?
Both have a free tier, so you can try either at no cost before committing.
What is OpenHAB best used for?
OpenHAB is most often used for self-hosted vendor neutral home automation hub, bridging smart home devices from different manufacturers under one set of rules. Of those, self-hosted vendor neutral home automation hub and bridging smart home devices from different manufacturers under one set of rules are not what Windmill is typically brought in for.
What can OpenHAB do that Windmill cannot?
OpenHAB covers Vendor Agnostic, Rule Engine, 200+ Bindings, Local Processing. Windmill covers Script-to-workflow engine, Auto-generated UIs, Self-hosted deployment, Git sync.

Answered from the vendors’ own pages

OpenHAB: How much does openHAB cost?

openHAB is 100% open source and completely free to download, install, and use across all supported platforms.

Source
Windmill: What does Windmill cost?

Windmill's Free and Open-source edition is $0/month for self-hosted use with unlimited executions, while Enterprise starts at $120/month with unlimited workspaces and uncapped SSO seats, priced further by developer/operator seats and compute units.

Source
OpenHAB: Are there any subscription fees for openHAB?

No, openHAB has no subscription fees. The software is free and released under an open source license for unlimited use.

Source
Windmill: Is there a free plan and what are its limits?

The free self-hosted plan supports unlimited executions but caps SSO at 10 users, workspaces at 3, groups/permissions at 4, and email triggers at 100 per day.

Source
OpenHAB: How can I support openHAB?

While openHAB is free to use, the project accepts voluntary donations through the openHAB Foundation to support development and maintenance.

Source
Windmill: How is usage metered on Windmill Enterprise?

Enterprise usage is metered through seats (developer seats at $20/month, operator seats at $10/month) and compute units, e.g. $100/month for 2 standard-worker compute units.

Source
Windmill: What happens to a self-hosted Windmill deployment if the company shuts down?

The pricing page addresses this directly as an FAQ topic, noting that self-hosted applications built on the open-source edition can continue running independently of Windmill the company.

Source
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