Source-Available on Your License

Business Source License 1.1

Mon, 01 Jan 0001 00:00:00 +0000

The Business Source License (BUSL) is source-available today and converts to an open-source license (chosen by the licensor, typically Apache-2.0 or GPL) on a pre-declared “Change Date”, typically four years after release. Until that date, commercial use outside a declared “Additional Use Grant” is restricted.

It is popular with venture-backed infrastructure companies that want to ship source code without giving competitors a free path to offer the software as a managed service.

Elastic License 2.0

Mon, 01 Jan 0001 00:00:00 +0000

Elastic License 2.0 (ELv2) is a short source-available license with three simple restrictions: you cannot provide the software as a managed service, you cannot circumvent license keys, and you cannot remove or alter licensing or copyright notices.

Everything else — use, modification, distribution, private use, commercial use in your own products — is allowed. ELv2 is much shorter than BUSL and does not have a conversion date.

ELv2 is not OSI-approved.

Fair code and source-available licenses

Mon, 01 Jan 0001 00:00:00 +0000

Fair code is an informal term for licenses that are:

source-available (the code can be read and often modified),
free to use in most scenarios, but
restricted in at least one dimension that makes them incompatible with the Open Source Definition.

The most common restrictions:

No hosting as a service — you cannot offer the software as a managed service that competes with the licensor. Examples: SSPL, Elastic License 2.0, Confluent Community License.
Non-commercial — you cannot use the software commercially without a separate agreement. Examples: PolyForm Noncommercial, Commons Clause derivatives.
Field of use — the software cannot be used in a named industry or for a named purpose. Examples: some Hippocratic-style licenses.
Time-delayed conversion — restricted now, becomes open source automatically after a specified period. Example: Business Source License (BUSL).

Why not just use an OSI licence?

Venture-backed infrastructure companies discovered a pattern: they build a piece of open-source software (MongoDB, Elasticsearch, Redis), a cloud provider forks it and offers it as a managed service, and the cloud provider out-competes the original authors on distribution because they already run the data plane.

Server Side Public License v1.0

Mon, 01 Jan 0001 00:00:00 +0000

SSPL is MongoDB’s response to the AGPL “loophole”: if you offer the software as a managed service, you must also release under SSPL the source code of every program you use to offer that service — provisioning, monitoring, orchestration, backup. In effect, it is strong copyleft extended to your service stack.

The OSI rejected SSPL as not meeting the Open Source Definition, specifically on Criterion 6 (no discrimination against fields of endeavour). It is therefore fair-code / source-available, not open source.