Last updated: 2026-08-05 · Plain text version of this document

Software Licenses

DRAFT — NOT YET IN FORCE. Items marked [VERIFY] need confirmation.

After Dark Systems, LLC publishes software under four licensing models. This page hosts the full texts for convenient reference.

The licence that governs any particular piece of software is the LICENSE file shipped in its repository. This page is a convenience copy. If this page and a repository ever disagree, the repository wins.

What we use

Model Full text Used for
MIT MIT License (text) client libraries, CLI tools, utilities
Functional Source License 1.1 FSL-1.1-MIT (text) [VERIFY: which products?]
Business Source License 1.1 BUSL-1.1 (text) [VERIFY: which products?]
Proprietary not published binary-only distributions

[VERIFY: a census of local repositories found 95 MIT and 20 Apache-2.0 licences, and no FSL or BSL anywhere. Either the FSL/BSL repositories are not on that machine, or the model is planned rather than current. Confirm which products actually ship under FSL and BSL before this table publishes.]

[VERIFY: Apache-2.0 is in use — claude-for-legal, rtk, rspamd-ads — but is not listed above. Either add it here or relicense those repositories.]

Source-available is not open source

The Functional Source License and the Business Source License are source-available licences. Neither is approved by the Open Source Initiative, and neither meets the Open Source Definition while the change period is running. Both convert to a genuine open source licence on a fixed date.

We are explicit about this because describing a source-available licence as "open source" is a misrepresentation that enterprise procurement and open source programme offices routinely check for.

[VERIFY: our OSS portal is named and described as an "open source software portal". If it lists FSL or BSL products, either the description or the listing needs to change.]

Our MIT-licensed software is open source in the full sense, with no restriction on commercial or competing use.

MIT

Permissive and unrestricted. You may use, modify, and redistribute the software, including commercially, provided you keep the copyright notice and licence text.

Full text: MIT License

Functional Source License 1.1

Source-available with a two-year change window. Two years after we make a version available, that version becomes available under the MIT licence.

While the change window runs, you may use the software for any purpose except a Competing Use — broadly, offering it to others in a product or service that substitutes for the software or for something else we offer. Internal use, non-commercial education, non-commercial research, and professional services to a licensee are all expressly permitted.

We use the FSL-1.1-MIT variant, so the future licence is MIT.

Full text: FSL-1.1-MIT

Business Source License 1.1

Source-available with a change date of up to four years. You may copy, modify, redistribute, and make non-production use of the software. Production use requires either a commercial licence from us or an Additional Use Grant.

BUSL-1.1 is a template, not a licence on its own. It is only a valid grant once these parameters are filled in:

Parameter Our value
Licensor After Dark Systems, LLC
Licensed Work [VERIFY: per product]
Additional Use Grant [VERIFY: or "None"]
Change Date [VERIFY: max 4 years from each version's publication]
Change License [VERIFY: must be GPL-compatible; MIT and Apache-2.0 both qualify]

A BUSL notice without those parameters completed grants nothing.

Full text: BUSL-1.1

Proprietary, binary-only

Some products are distributed as binaries under a proprietary licence with no source release. Terms are set in the applicable order form or agreement, and the Terms of Service (plain text) apply.

Distributing only binaries does not remove our obligation to attribute the third-party open source components inside them. See below.

Third-party components

Our software includes third-party open source components. Their licences continue to apply to those components, and several — MIT, BSD, and Apache-2.0 among them — require us to reproduce their copyright notices when we distribute.

[VERIFY: no NOTICE or third-party attribution file currently exists in the repositories checked, including the Apache-2.0 ones where section 4(d) requires passing the NOTICE file along. This obligation attaches to distribution in any form, including binary-only. It needs generating per distributed artefact.]

Attribution for a specific product is available on request from legal@afterdarksys.com, and a Software Bill of Materials can be provided to customers under agreement.

Questions