In short
The Sustainable Use License is a software licence published by n8n in March 2022 that makes the source code openly accessible but restricts use to your own internal business purposes and to non-commercial and personal purposes — making it the best-known representative of the fair-code licensing model shaped by n8n and explicitly not an open-source licence in the sense of the Open Source Initiative.
In practice, the term almost always comes up at the same moment: a company wants to run an automation, database or search system itself, reads "source code on GitHub" and concludes "so it's open source, so I can do anything". It is exactly this equation that does not hold for fair-code. The distinction is not hair-splitting among licensing lawyers; it decides whether a planned business model — such as a hosted automation platform for customers — is permitted at all.
What "fair-code" means — and what it is not
Fair-code is not itself a licence. The initiative behind faircode.io explicitly describes it as a software model covering several specific licences. The definition names four characteristics: the software is generally free to use and may be distributed by anyone, its source code is openly visible, it can be extended by anyone in public and private communities — and it is commercially restricted by its authors.
The last point is the decisive one. It is also where the model parts ways with open source. In its Open Source Definition, the Open Source Initiative states under point 6 ("No Discrimination Against Fields of Endeavor") that a licence must not restrict anyone from using the software in a specific field of endeavour — explicitly including business use. A clause that limits use to "internal business purposes" is not compatible with this definition. n8n itself draws this conclusion and consistently describes its own product not as open source but as fair-code.
The licences that fall under fair-code
faircode.io lists several existing licences as fair-code compliant, including MariaDB's Business Source License (BSL/BUSL), the Commons Clause in combination with an OSI-approved licence, the Confluent Community License, the Elastic License 2.0, MongoDB's Server Side Public License (SSPL) and the Sustainable Use License. Projects using compatible licences include Airbyte, CockroachDB, Elastic, HashiCorp, MongoDB, Sentry and n8n. According to the site, there is no connection between the fair-code initiative and these organisations — the list is a classification, not a membership.
The wording of the Sustainable Use License
The licence is deliberately kept short and written in plain English. The relevant section is simply called "Limitations" and is in the LICENSE.md of the n8n repository. In essence it says: you may use or modify the software only for your own internal business purposes or for non-commercial or personal use. You may distribute the software or provide it to others only if you do so free of charge for non-commercial purposes. You may not alter, remove or obscure any licensing, copyright or other notices; use of the licensor's trademarks is subject to applicable law.
Before that comes a surprisingly far-reaching grant of rights: a non-exclusive, royalty-free, worldwide, non-sublicensable, non-transferable licence to use, copy, distribute, make available and prepare derivative works of the software — in each case subject to the limitations mentioned. In addition, there is a patent licence with a customary retaliation clause (anyone who accuses the licensor of patent infringement loses their patent licence immediately), an obligation to pass on the licence terms themselves, a labelling obligation for modified copies, a disclaimer of warranty and liability, and a termination clause.
This termination clause is more important in practice than it looks: anyone who uses the software in breach of the licence loses the licence automatically. If the licensor points out the breach and it is remedied within 30 days, the licence is reinstated retroactively. A further breach after such reinstatement, however, leads to automatic and permanent termination.
Where exactly the line runs
The dividing line runs not between "free" and "paid" but between your own use and exploiting the software as a product. Running it within your own company is unproblematic, even in a group with several thousand employees, and even for processes with which the company earns money. It becomes problematic when the software itself becomes the subject of the offering — for example as a hosted instance made available to third parties for a fee.
What is remarkable is what the Sustainable Use License explicitly opened up compared with its predecessor. Until 17 March 2022, n8n was under Apache 2.0 with the Commons Clause. In the announcement of the licence change, founder Jan Oberhauser names two changes: the definition of permitted use was clarified from "selling" to "internal business purposes" — and the restriction on consulting and support services was lifted completely. So anyone who builds n8n workflows or custom nodes for customers and charges a fee for this no longer needs a separate agreement. With Elastic's consent, the Elastic License 2.0 served as the basis for the licence text.
Distinction: open source, fair-code and source-available
The terms are regularly mixed up in marketing. The following overview classifies the common models according to what they actually permit:
| Model / licence | Source code visible | Commercial own use | Can be resold as a hosted service | OSI-compliant |
|---|---|---|---|---|
| Permissive (MIT, Apache 2.0) | yes | yes | yes | yes |
| Copyleft (GPL, AGPL) | yes | yes | yes, subject to disclosure obligations | yes |
| Sustainable Use License (fair-code) | yes | yes, for internal business purposes | no | no |
| Elastic License 2.0 | yes | yes | no | no |
| Business Source License (BSL/BUSL) | yes | yes, with a usage limit | no, until the change date | no |
| Server Side Public License (SSPL) | yes | yes | only if the entire service stack is disclosed | no |
All rows below the copyleft row fall under the umbrella term source-available: the code is readable, but use is contractually limited. Fair-code is a subset of this with a specific stance — the author reserves commercialisation as a hosted service but releases everything else.
Why vendors choose this model
The motive is rarely ideological but economic. An open-source project that becomes successful can be taken over by a cloud hyperscaler, packaged as a managed service and sold without any significant share of the revenue reaching the developers. The fair-code initiative describes this as an "economic decoupling" between those who do the work and those who profit from it. The Sustainable Use License closes precisely this gap: anyone who wants to offer the software commercially as a service has to come to the negotiating table.
The price for this is real. Projects under fair-code lose access to distributions that only accept OSI-compliant licences, they drop out of many open-source funding programmes, and in tenders with a hard "open source" requirement they are formally not eligible. Whether this trade-off works out depends on the business model — there is no universally valid answer.
What this means for mid-sized companies that self-host
For the vast majority of companies that run such software themselves, the licence changes practically nothing. It becomes relevant in a few clearly identifiable places:
- Internal operation is covered. Your own servers, your own workflows, your own employees, your own data — this is the core case for which the licence was written. Company size and profit motive play no role.
- Consulting and implementation are allowed. An agency may develop workflows for customers and charge a fee for this. This restriction was dropped in 2022.
- The multi-tenant case is the critical one. As soon as an instance is operated whose use is sold to third parties as a service, you leave the permitted area. Anyone planning something like this needs a commercial agreement with the vendor.
- Enterprise features are licensed separately. At n8n, this applies to all source files with
.ee.in the file name or.eein the directory name — these are not under the Sustainable Use License but require a valid enterprise licence. - Only the main branch is licensed. According to LICENSE.md, content in branches other than
masteris explicitly not licensed. Anyone building from a feature branch should know this.
Everything beyond these basic cases — group structures with legally independent subsidiaries, joint ventures, white-label constructions — should be legally reviewed on a case-by-case basis. The licence does define "your company" in terms of control relationships, but that does not settle how the specific facts are classified.
A real-world example: n8n
n8n is the reference project for the Sustainable Use License — the licence text sits in the project's main repository, and n8n founder Jan Oberhauser is also one of the initiators of faircode.io. The workflow automation platform can be completely self-hosted, the code is visible, and custom nodes can be written and published. In addition, n8n runs its own cloud variant and sells enterprise licences — the monetisation track that the licence keeps free.
Other projects with fair-code-compatible licences include Airbyte and Nango (Elastic License 2.0), CockroachDB and Sentry (Business Source License) and MongoDB (SSPL). According to n8n, the Sustainable Use License itself is explicitly open for use by other projects too.
Risks and misconceptions
The biggest misconception is confusing it with open source — with the result that companies set up a product venture that the licence does not cover and only notice once sales and the roadmap are already in place.
The second risk is structural and can be read from recent industry history: licences change. In 2021, Elastic switched from Apache 2.0 to the SSPL and Elastic License 2.0, whereupon AWS forked Elasticsearch as OpenSearch. In 2023, HashiCorp moved Terraform and other products to the Business Source License; the community responded with OpenTofu. In March 2024, Redis switched from the BSD model to RSALv2/SSPLv1 — a few days later, the fork Valkey was launched under the umbrella of the Linux Foundation. The counter-movement is remarkable: in 2024, Elastic added AGPLv3 as an additional licence option, and in May 2025 Redis also placed Redis 8 under AGPLv3.
The lesson from this is not "fair-code is dangerous" but simpler: the licence of a strategically important system is a variable, not a constant. Anyone who builds a platform deep into their processes should know how expensive a switch — to a fork, to a commercial subscription, to another product — would be in an emergency.
A third, often overlooked detail: fair-code licences are not standard contracts with decades of case law behind them. Terms such as "internal business purposes" are not established in German law and may need interpretation in case of doubt. For borderline cases, a lawyer's assessment is the only reliable answer.
Outlook
The dispute between OSI-compliant openness and economically protected intermediate models has not been decided. On the one hand, the market's fork reaction has shown that restrictive licence changes can become expensive; on the other hand, several vendors have subsequently added AGPL options without giving up their commercial restrictions elsewhere. For users, this above all means: the licence question belongs in the evaluation, and before the architecture decision, not after it.
Frequently asked questions
Is n8n open source?
No. The source code is openly visible, but the Sustainable Use License restricts use to internal business purposes and non-commercial and personal use. Because the OSI's Open Source Definition rules out such restrictions on use, n8n does not describe itself as open source but as fair-code.
May a company use software under the Sustainable Use License commercially?
Yes, for its own internal business purposes — even if revenue is generated with it. What is prohibited is passing on the software itself to third parties for a fee or offering it as a hosted service.
May an agency charge for consulting and implementation?
Yes. The restriction on consulting and support fees that was contained in the earlier combination of Apache 2.0 and the Commons Clause was lifted with the switch to the Sustainable Use License in March 2022.
How does the Sustainable Use License differ from the SSPL?
The SSPL generally also permits offering the software as a service, but in return requires disclosure of the entire service stack needed for operation under the same licence — a condition that can hardly be met in practice. The Sustainable Use License prohibits this case directly, without the detour via a disclosure obligation.
What happens in the event of a licence breach?
According to its wording, the licence ends automatically. If the breach is remedied within 30 days of a notice from the licensor, it is reinstated retroactively; a further breach after that ends it automatically and permanently. How this plays out under German law in a specific case needs to be legally reviewed on a case-by-case basis.