The Business Source License is a time limited license. Source is available now, non production use is free, and production use follows the licensor's Additional Use Grant. On a stated Change Date the code converts to an open license, which is GPL version 2 or later or a compatible one, per the MariaDB FAQ.
The three terms to find in the header
Every BSL project fills in a header. Read these three lines before anything else.
- Additional Use Grant. Says what production use is allowed without paying. It might permit use below a size threshold, or it might say none.
- Change Date. The date the license changes. The FAQ describes the maximum as four years after the first public distribution under the BSL.
- Change License. What the code becomes on that date. The FAQ names GPL version 2 or later, or a compatible license.
The terms are set per project, so two BSL products can behave very differently. Do not assume the numbers from one apply to another.
Production versus non production
The FAQ states that non production use is always free. Production use depends on the grant. That means a proof of concept on a laptop and a customer facing deployment are different questions, even for the same package.
A common mistake is to approve a component during evaluation and then ship it without revisiting. Put a note on your approval that it covered evaluation only.
What the change date does and does not do
After the Change License takes effect, you can use that version under the open license. It applies to the version covered by the date. Newer releases usually carry their own BSL header with a later Change Date, so the freedom attaches to older code, not to the version you are running next year.
This matters for upgrade planning. If you pin to a version whose Change Date has passed, your obligations are those of the change license. If you track latest, you are back under the BSL terms of that release.
Is it open source?
The MariaDB page says source code is guaranteed to become open source at a certain point in time. It does not describe the BSL itself as open source before then. The Open Source Definition rules out restrictions on fields of endeavor, and a limit on production use is a usage restriction. Most policies therefore treat BSL as source available until the Change Date.
A review routine
- Record the exact header text, not a summary of it.
- Check whether your production use fits the grant today and in 12 months.
- Calendar the Change Date and the version it applies to.
- Note the fallback: pay, replace, or pin an older converted version.
Safeguard can list the components in a build through SBOM and dependency scanning, so you know where a BSL package sits. The free scan is a quick way to start. License interpretation stays with your counsel.
Quick check
Is non production use of BSL code free?
According to the MariaDB FAQ, yes. Production use is governed by the Additional Use Grant.
Does the change date free every future version?
No. It converts the version it covers. Later releases normally have their own header and Change Date.
Sources
This post is general information, not legal advice.
Last reviewed: 19 October 2026.
