License
| Component | License | Covers |
|---|---|---|
Brain (z4j-brain) | AGPL-3.0-or-later | Dashboard, REST API, WebSocket server, Postgres models |
Umbrella (z4j) | AGPL-3.0-or-later | Meta-package; pip install z4j pulls in z4j-brain and therefore carries the same licence |
Agent packages (every other z4j-*) | Apache 2.0 | z4j-core, z4j-bare, z4j-django, z4j-flask, z4j-fastapi, z4j-celery, z4j-rq, z4j-dramatiq, z4j-huey, z4j-arq, z4j-taskiq, and all six scheduler adapters |
Three install paths, three licence outcomes
Section titled “Three install paths, three licence outcomes”| Command | What you install | Licence you end up with |
|---|---|---|
pip install z4j or pip install "z4j[...]" | Brain + core + optional adapters | AGPL-3.0-or-later |
pip install z4j-<framework> z4j-<engine> | Agents only | Apache 2.0 |
docker run z4jdev/z4j | Brain in a container; your app venv untouched | Brain AGPL-3.0 (isolated); app agents Apache 2.0 |
The umbrella is AGPL because it installs AGPL code by default, not because its own __init__.py contains anything substantive. If AGPL is incompatible with your environment, install the individual agent packages directly — they are all Apache 2.0 and carry no copyleft obligation.
What this means for you
Section titled “What this means for you”Self-hosting the brain
Section titled “Self-hosting the brain”Free. Forever. You can run z4j-brain for your own organization without any obligation beyond AGPL compliance (which, for internal use, means nothing extra — AGPL triggers on network distribution, not internal deployment).
Building on agents
Section titled “Building on agents”Apache 2.0. Your application code is not AGPL-tainted. You can use z4j agents in proprietary software with no license concern — as long as you install the agent packages directly (not via the z4j umbrella, which pulls in the AGPL brain transitively).
SaaS-ifying the brain
Section titled “SaaS-ifying the brain”If you take z4j-brain and serve it to other companies over a network (i.e., you build a hosted z4j as a SaaS), AGPL requires you to publish your modifications. This is by design - we want a level playing field.
Commercial license
Section titled “Commercial license”If your organization can’t use AGPL (legal policy, compliance, whatever), contact licensing@z4j.com for a commercial license. No gotchas.
Commitments
Section titled “Commitments”- Every released version keeps its license permanently. We never retroactively re-license.
- Security fixes always ship in the open-source release on the same day as any commercial release.
- The roadmap is public. We announce commercial direction openly.
Why AGPL + Apache (not MIT everywhere)
Section titled “Why AGPL + Apache (not MIT everywhere)”MIT-everywhere enables SaaS competitors to wrap your project without contributing back. We want:
- Agents in your app → no friction → Apache 2.0.
- Brain as infrastructure → contribute back if you SaaS-ify → AGPL.
This is the same pattern PostHog, Plausible, Minio, and others use.
No “free forever” pledge
Section titled “No “free forever” pledge”We make no “free forever” pledge because we’ve seen other projects make that claim then walk it back. What we commit to:
- License stability on shipped releases.
- Open roadmap.
- Honest communication.
- Security parity between open-source and any future commercial offering.
Contributor license
Section titled “Contributor license”Contributors sign off with DCO (Developer Certificate of Origin). No CLA. See CONTRIBUTING.md in the repo.