Software Licenses
=================

After Dark Systems — legal.afterdarksys.com
Last updated: 2026-08-05

> **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](license-mit.html) ([text](license-mit.txt)) | client libraries, CLI tools, utilities |
| Functional Source License 1.1 | [FSL-1.1-MIT](license-fsl-1-1-mit.html) ([text](license-fsl-1-1-mit.txt)) | `[VERIFY: which products?]` |
| Business Source License 1.1 | [BUSL-1.1](license-busl-1-1.html) ([text](license-busl-1-1.txt)) | `[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](license-mit.html)

## 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](license-fsl-1-1-mit.html)

## 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](license-busl-1-1.html)

## 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](terms.html) ([plain text](terms.txt)) 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

- Licensing and commercial terms: legal@afterdarksys.com
- Security: security@afterdarksys.com