Licensing
Soul Stack is fair-code: the source is open and available, but offering the product to third parties as a commercial service is restricted. Here is how that works and what you are allowed to do.
In brief
Section titled “In brief”| Component | License | Meaning |
|---|---|---|
Core — Keeper, Soul, soulctl, soul-lint, the built-in core.* modules | BSL 1.1 (fair-code) → after 2 years each version becomes Apache 2.0 | source is open; production use is broadly permitted, except reselling it as a hosted/managed service |
| Web interface (soul-stack-web) | BSL 1.1 → Apache 2.0 | same as the core |
SDK, examples, plugins (sdk/*, examples/, official/community soul-mod-*) | Apache 2.0 | fully free, including proprietary third-party plugins |
| Premium packs, enterprise modules (later) | commercial | separate products on top of the open core |
What BSL is and why it isn’t “full open source”
Section titled “What BSL is and why it isn’t “full open source””BSL (Business Source License) 1.1 is the same model used by MariaDB, Sentry, CockroachDB, HashiCorp, and n8n. The source is open — you can read, build, modify, and run it in production — with one restriction: you may not offer Soul Stack to third parties as a hosting/managed service. After 2 years each specific version automatically becomes Apache 2.0 — fully open software. It is a sliding window: today’s version becomes Apache in two years, the next one two years after its own release.
We chose fair-code rather than going fully closed or pure Apache because:
- Trust requires openness. Soul Stack installs an agent and handles secrets on your servers — the source must be available for audit.
- Return to the commons. The Change Date guarantees that every version eventually becomes Apache 2.0 — the restriction is temporary, not permanent.
Why the SDK and plugins are Apache 2.0
Section titled “Why the SDK and plugins are Apache 2.0”The ecosystem should grow without friction. Plugins are separate processes that talk to the core over gRPC and are not legally a derivative work of the core. So the SDK, examples, and plugins are under Apache 2.0: authors are free to publish their modules under any license, including proprietary paid plugins. The BSL restriction covers only reselling the core itself as a service, not writing extensions for it.
Brand and “official”
Section titled “Brand and “official””The name, the logo, and the “official” / “certified” / “official managed” statuses are protected by trademark, not by the code license. Allowed: self-hosting, training, plugin development, stating compatibility. Not allowed: calling a fork “Soul Stack”, selling a “certification” or “official managed” status in our name.
Common questions
Section titled “Common questions”Can I use Soul Stack for free at a commercial company? Yes — to manage your own infrastructure, including in commercial operation. The restriction only covers reselling Soul Stack to third parties as a service.
What exactly becomes Apache 2.0, and when? Each specific version of the core and the web UI — 2 years after its first public release. The restriction lifts automatically, retroactively for that version.
Does my plugin have to be open source? No. The SDK and plugins are Apache 2.0; you can publish your own plugin under any license, including a proprietary, paid one.