Plugin Developer FAQ

Which commercial instrument (Q-17, 2026-09-16). Where this page says a use requires a commercial licence, the instrument is the versioned Customer Agreement, issued at 1.0.0. The conditional wording here is licensing policy and is unchanged by that issue; what changed is that the instrument it points to now exists. No “Stella Ops Commercial Licence/EULA” document exists, and no surface may claim one.

Document Version: 2.0.0 Last Updated: 2026-10-27

This FAQ addresses common questions from plugin developers working with the Stella Ops Community Plugin Grant. For the full legal terms, see LICENSE-ADDENDUM-COMMUNITY-PLUGIN-GRANT.md in the repository root.

General Questions

Q1: What constitutes a “Plugin” under the Community Plugin Grant?

A: A Plugin is a separately packaged extension that interfaces with Stella Ops using documented public plugin APIs or integration points. This includes:

Examples of Plugins:

NOT Plugins (derivative works requiring BUSL-1.1 compliance):

Q2: Can I sell my plugin commercially?

A: Yes. You may develop and sell plugins commercially under license terms of your choosing (including proprietary terms), provided:

  1. Your plugin does not include, copy, or modify Stella Ops source code; AND
  2. You comply with the attribution requirements (see Q4).

Your commercial plugin license is entirely separate from the BUSL-1.1 license covering Stella Ops itself.

Q3: Do I need to open-source my plugin?

A: No. Plugins that interface with Stella Ops through public APIs do not need to be open-sourced. You may use any license you choose, including proprietary licenses.

Exception: If your plugin includes, copies, or modifies any portion of Stella Ops source code, it becomes a derivative work subject to BUSL-1.1.

Q4: What attribution is required when distributing a plugin?

A: When distributing a plugin, you should:

  1. Acknowledge compatibility: State that your plugin is designed for use with Stella Ops (e.g., “Compatible with Stella Ops Suite”)

  2. Include license reference: If your plugin distribution includes any Stella Ops components (even configuration samples), include the LICENSE and NOTICE files

  3. Link to source: Provide a link to the Stella Ops source repository (https://git.stella-ops.org)

Minimum attribution example:

This plugin is designed for use with Stella Ops Suite.
Stella Ops is licensed under BUSL-1.1. See https://git.stella-ops.org

Usage Limits

Q5: What is the free usage limit?

A: Production use is free if each Installation manages no more than twenty (20) Placements at any time (Additional Use Grant §2 in LICENSE). Addendum 2.0.0 refers to that limit and states no separate one. The number of Environments is not limited.

A Placement is one active Managed Workload–Environment relationship. A Managed Workload is a container service, or an artifact deployed to a host, whose releases the Installation gates, promotes or deploys, or whose image or deployable artifact the Installation scans, or to which it applies the results of an earlier scan, while that image or artifact is installed as part of the workload in an Environment. Replicas, restarts, redeployments, image or version changes, repeated scans and reports of the same workload in the same Environment add no Placement. Stella Ops’ own components are not Placements.

Plugin development and distribution do not depend on any Placement count: building, publishing or distributing a Plugin creates no Placement (Addendum 2.0.0 §2).

Example scenarios:

ScenarioPlacements
One service in Dev + Staging + Prod3
Ten services in three Environments30 (above the free limit)
One service with five replicas in one Environment1
A new image version of a deployed service+0

Q6: Do scans count against the limit?

A: There is no per-scan charge. Scanning an installed workload’s image or artifact, or applying an earlier scan result to it, can bring that workload into the Placement count for each applicable Environment. Each workload–Environment relationship counts only once, regardless of the number of scans or reports. SBOM and VEX generation add nothing. Scanning an image or artifact installed in no Environment does not, by itself, create a Placement.

A workload–Environment relationship can count when Stella deploys, gates or promotes its releases, scans its installed image or artifact, or applies an earlier scan result to that installed workload. Applying an earlier result does not require a new scan to run. Each qualifying relationship counts once, even when several of these activities apply. Merely retaining or viewing a report solely as historical evidence does not create a Placement. Presenting an earlier result as applicable scan information for an installed workload counts as applying that result.

Q7: What happens if my users exceed the free limit?

A: If users of your plugin manage more than twenty Placements in an Installation:

  1. They need paid Placement capacity through an accepted order under the Licensor’s Customer Agreement - the user (not the plugin developer) is responsible for licensing compliance
  2. Your plugin continues to work - nothing in the plugin or in Stella Ops counts, throttles or blocks use against the licence

As a plugin developer, you should:

Bundling & Distribution

Q8: Can I bundle Stella Ops core with my plugin?

A: This depends on how you bundle:

Allowed (aggregation):

Requires BUSL-1.1 compliance (derivative work):

Requires commercial license:

Q9: Can I create a plugin that modifies Stella Ops behavior at runtime?

A: Yes, if the modification uses documented extension points:

Allowed:

Not allowed without BUSL-1.1 derivative work compliance:

The key distinction is whether you’re using documented public APIs (allowed) vs. undocumented internal behavior (derivative work).

Commercial Considerations

Q10: Can my plugin be used in Installations that hold a paid subscription?

A: Yes. Every Installation runs the same software, and a subscription changes only the number of Placements the Licensor permits. Subscribers may use community plugins subject to their own agreement with the Licensor. Stella Ops offers no hosted (SaaS) edition.

Q11: Do I need Licensor approval to publish a plugin?

A: No. You do not need approval from stella-ops.org to:

However, stella-ops.org may maintain an official plugin registry with quality/security standards for listed plugins.

Q12: Can MSPs provide plugins to their managed customers?

A: Yes, with these considerations:

  1. Plugin distribution: MSPs can freely distribute plugins to customers
  2. Stella Ops licensing: Each customer deployment must comply with BUSL-1.1:
    • Within the free usage limit; OR
    • Covered by the MSP’s commercial arrangement with e-Solutions EOOD; OR
    • Customer has their own commercial arrangement

See docs/legal/SAAS_MSP_GUIDANCE.md for detailed MSP scenarios.

Edge Cases

Q13: Does the Community Plugin Grant apply to unofficial API integrations?

A: The grant specifically covers plugins using “documented public plugin APIs or integration points.” For unofficial or undocumented APIs:

Recommendation: Use documented APIs for stable, supported integration.

Q14: Can I fork Stella Ops and call it something else?

A: Forking is allowed under BUSL-1.1, but:

  1. BUSL-1.1 applies to the fork - Production use requires compliance with the Additional Use Grant or a commercial license
  2. Attribution required - You must preserve LICENSE, NOTICE, and copyright notices
  3. No trademark use - You may not use Stella Ops trademarks for your fork
  4. Change Date applies - After the Change Date (2030-01-20), the fork converts to Apache-2.0

Q15: What if my plugin is used beyond the free usage limit?

A: If your plugin is used in Installations beyond the free usage limit:

  1. Users are responsible for licensing - Not you as the plugin developer
  2. Consider partnership - Contact stella-ops.org about potential partnership or revenue sharing arrangements
  3. Document clearly - Ensure your plugin documentation explains licensing requirements

Q16: Can I host a free scanning service for the community using my plugin?

A: The BUSL-1.1 restriction specifically targets “public multi-tenant paid hosting.” Non-commercial, free-of-charge hosting for community benefit may be eligible for the Community Program.

Potentially eligible:

Not eligible (requires commercial license):

Process: Apply to the Community Program at community@stella-ops.org. Approval is not automatic and is evaluated based on genuine community benefit.

See docs/legal/SAAS_MSP_GUIDANCE.md Section 4.3 for detailed guidance.

Getting Help

Technical questions about plugin development:

Licensing questions:

Subscriptions:

See Also

Document maintained by: Legal + Developer Relations Last review: 2026-10-27