Source-Available at Erdikon

Open source has a clear definition. A license only counts as open source if it meets the Open Source Definition of the Open Source Initiative. Among other things, a license must allow modifications to the software and must not exclude any field of use.

Source-available describes a model between open source and proprietary software. The source code can be reviewed, and the software can be used and extended under its license terms. Certain rights, however, are reserved for its authors. In the Erdikon License, this only concerns the license key functionality, which you may not change.

The license allows you to use, copy, modify, and pass on Erdikon. This applies to personal and commercial purposes alike. You may run Erdikon on your own servers, review the source code, and adapt the software to your workflows.

You may pass on copies of Erdikon, including modified versions, and you may charge for them. When you do, you must include the license terms and clearly mark modified versions as modified.

You may offer paid services around Erdikon, such as installation, customization, integration, hosting, support, and maintenance. This applies on your own infrastructure as well as on your customers' infrastructure. You may also offer Erdikon as a cloud service where customers sign up on their own.

If you run Erdikon for customers, they must be able to create and download a complete backup of their data, files, and configuration at any time and free of charge. The backup must include everything needed to restore Erdikon in an independent installation without your help. This keeps your customers independent, even when they outsource operations.

You may not circumvent, change, move, or disable the license key functionality. You also may not remove or obscure features that the license key protects. Among other things, the license key controls the limits of the Free plan. If you want to run Erdikon for more than two people, you therefore need a paid plan or the perpetual license. This also applies if you run Erdikon for customers.

If a single installation serves multiple tenants, such as several customers in a cloud service, each tenant needs its own valid license key. This can also be a free license key for the Free plan. Tenants may not share a license key.

Copyright and license notices in the software must remain intact.

What happens if license keys for Erdikon can no longer be bought? The license includes an exception for this case. If license keys are generally unavailable for at least 30 consecutive days, you may temporarily circumvent the license key restrictions. Once license keys are available again, this permission ends, and you must restore the restrictions.

The exception only applies if ordinary customers cannot buy license keys. Failed payments, restricted accounts, a refusal to sell to a particular customer, or a price you do not want to pay do not count.

This way, you can keep using Erdikon even if license keys can no longer be bought.

	Open source	Erdikon License
View the source code	Yes	Yes
Use it commercially	Yes	Yes
Self-host it	Yes	Yes, on any plan or with a perpetual license
Modify it	Yes	Yes, except for the license key functionality
Pass on copies	Yes, also for a fee	Yes, also for a fee
Installation, hosting & support for customers	Yes	Yes
Offer a self-service cloud	Yes, with conditions depending on the license	Yes
Complete backup when hosting for customers	Not required	Required, at any time & free of charge
Circumvent license keys	Yes	Only if license keys are unavailable

The Erdikon License therefore only differs from an open source license when it comes to the license key. Anyone who uses Erdikon beyond the Free plan needs a license key, no matter who runs the software.

Erdikon has to pay for itself. Development, maintenance, security updates, and support take time. Revenue from the plans and the perpetual license funds this work.

With an open source license, any company could remove the license check and run, distribute, or sell Erdikon as a cloud service without a license key. The revenue would then go to those who run the software rather than to those who develop it. Projects such as Elasticsearch and MongoDB changed their licenses for this reason and restricted offering their software as a cloud service.

The Erdikon License, on the other hand, does not restrict who may offer Erdikon. It only ensures that a license key is bought for use beyond the Free plan, and in a cloud service for each tenant. IT service providers and hosting providers can introduce, adapt, and run Erdikon and earn money doing so. This mainly benefits SMEs that want to choose their provider freely or need personal support.

The source-available model protects this funding without giving up the key benefits of open source. You can review the source code, run Erdikon yourself, and adapt it to your needs. The requirement for complete backups and the rule on license key availability ensure that you do not become dependent on Erdikon itself or on a service provider.

For digital sovereignty, what matters is that companies keep control over their data and software and can choose their provider freely. The Erdikon License allows both.

The binding terms are in the Erdikon License. This article summarizes them but does not replace them.