The open-core model is a business model for the monetization of commercially produced open-source software. The open-core model primarily involves offering a "core" or feature-limited version of a software product as free and open-source software, while offering "commercial" versions or add-ons as proprietary software. [1] [2] The term was coined by Andrew Lampitt in 2008. [3] [4]
The concept of open-core software has proven to be controversial, as many developers do not consider the business model to be true open-source software. Despite this, open-core models are used by many open-source software companies. [5]
Some open-core products require their contributors to sign a contributor license agreement, which either dictates that the copyright of all contributions to the product become the property of its owner, or that the product's owner is given an unlimited, non-exclusive license to use the contributions, but the authors retain copyright ownership. In an open-core scenario, these agreements are typically meant to allow the commercial owner of the product (which in some cases, is ultimately the copyright holder to all of its code, regardless of its original author) to simultaneously market versions of the product under open-source and non-free licenses. This is in contrast with more traditional uses of CLAs, which are meant solely to allow the steward of an open-source project to defend and protect the copyrights of its contributors, or to guarantee that the code will only ever be made available under open-source terms (thus protecting it from becoming open core). [6] [7] [8]
A new variation of the practice emerged in 2018 among several open core products intended for server-side use, seeking to control use of the product as part of a service offered to a customer. These practices, in particular, target incorporation of the software into proprietary services by cloud application service providers such as Amazon Web Services, but with what vendors perceive to be inadequate compensation or contributions back to the upstream software in return. [24] [25]
MongoDB changed its license from the GNU Affero General Public License (a variation of the GPL which requires that the software's source code be offered to those who use it over a network) to a modified version titled the "Server Side Public License" (SSPL), where the source code of the entire service (including, without limitation, all code needed for another user to run an instance of the service themselves) must be released under the SSPL if it incorporates an SSPL-licensed component (unlike the AGPL, where this provision only applies to the copyrighted work that is licensed under the AGPL). [26] Bruce Perens, co-author of The Open Source Definition, argued that the SSPL violated its requirement for an open source license to not place restrictions on software distributed alongside the licensed software. [24] The Open Source Initiative (OSI) ruled that the SSPL violates the Open Source Definition and is therefore not a free software license, as the provision discriminates against commercial users. [27] Debian, Fedora, and Red Hat Enterprise Linux pulled MongoDB from their distributions after the license change, considering the new license to be in violation of their licensing policies. [26] [28]
Redis Labs made its Redis plugins subject to the "Commons Clause", a restriction on sale of the software on top of the existing Apache License terms. After criticism, this was changed in 2019 to the "Redis Source Available License", a non-free license which forbids sale of the software as part of "a database, a caching engine, a stream processing engine, a search engine, an indexing engine or an ML/DL/AI serving engine". [29] [25] [30] The last versions of the modules licensed solely under the Apache License were forked and are maintained by community members under the GoodFORM project. [24] A similar move was made when HashiCorp switched to the non-free Business Source License (BSL) on its products, including Terraform, which received the Linux Foundation-backed fork OpenTofu. [31]
In September 2024, WP Engine—a hosting provider that uses the free and open source WordPress software—began to face criticism from Matt Mullenweg—the founder of the project's corporate sponsor Automattic, and owner of the competitor WordPress.com. During a presentation and blog post, he criticized WP Engine over inadequate upstream contributions, disabling of features, private equity funding, and trademark dilution of the "WP" prefix. He called the company a "cancer" to WordPress, and called for a boycott of its services. [32] WP Engine sent a cease and desist to Automattic demanding the removal of the comments, stating that they operated within the WordPress Foundation trademark usage guidelines, and that Automattic had been demanding "significant percentage of its gross revenues" in licensing fees. [33] While WordPress is licensed under the GNU General Public License, Mullenweg began to enforce restrictions against WP Engine by banning it from any services hosted under the WordPress.org domain, including automatic updates and the ability to download plug-ins and themes from within the software. The trademark guidelines were also modified to cover use of "WP". [34] In October 2024, WP Engine formally filed a lawsuit against Automattic for defamation and extortion. [35]
BitKeeper is a discontinued software tool for distributed revision control of computer source code. Originally developed as proprietary software by BitMover Inc., a privately held company based in Los Gatos, California, it was released as open-source software under the Apache-2.0 license on 9 May 2016. BitKeeper is no longer being developed.
Source-available software is software released through a source code distribution model that includes arrangements where the source can be viewed, and in some cases modified, but without necessarily meeting the criteria to be called open-source. The licenses associated with the offerings range from allowing code to be viewed for reference to allowing code to be modified and redistributed for both commercial and non-commercial purposes.
Matthew Charles Mullenweg is an American web developer and entrepreneur. He is known as a co-founder of the free and open-source web publishing software WordPress and the founder of Automattic.
XWiki is a free and Open source wiki software platform written in Java with a design emphasis on extensibility. XWiki is an enterprise wiki. It includes WYSIWYG editing, OpenDocument-based document import/export, annotations and tagging, and advanced permissions management.
Multi-licensing is the practice of distributing software under two or more different sets of terms and conditions. This may mean multiple different software licenses or sets of licenses. Prefixes may be used to indicate the number of licenses used, e.g. dual-licensed for software licensed under two different licenses.
The GNU Affero General Public License is a free, copyleft license published by the Free Software Foundation in November 2007, and based on the GNU GPL version 3 and the Affero General Public License (non-GNU).
A Contributor License Agreement (CLA) defines the terms under which intellectual property has been contributed to a company/project, typically software under an open source license.
An embedded database system is a database management system (DBMS) which is tightly integrated with an application software; it is embedded in the application. It is a broad technology category that includes:
Companies whose business centers on the development of open-source software employ a variety of business models to solve the challenge of making profits from software that is under an open-source license. Each of these business strategies rest on the premise that users of open-source technologies are willing to purchase additional software features under proprietary licenses, or purchase other services or elements of value that complement the open-source software that is core to the business. This additional value can be, but not limited to, enterprise-grade features and up-time guarantees to satisfy business or compliance requirements, performance and efficiency gains by features not yet available in the open source version, legal protection, or professional support/training/consulting that are typical of proprietary software applications.
MongoDB is a source-available, cross-platform, document-oriented database program. Classified as a NoSQL database product, MongoDB utilizes JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and current versions are licensed under the Server Side Public License (SSPL). MongoDB is a member of the MACH Alliance.
Redis is a source-available, in-memory storage, used as a distributed, in-memory key–value database, cache and message broker, with optional durability. Because it holds all data in memory and because of its design, Redis offers low-latency reads and writes, making it particularly suitable for use cases that require a cache. Redis is the most popular NoSQL database, and one of the most popular databases overall. Redis is used in companies like Twitter, Airbnb, Tinder, Yahoo, Adobe, Hulu, Amazon and OpenAI.
Elasticsearch is a search engine based on Apache Lucene. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents. Official clients are available in Java, .NET (C#), PHP, Python, Ruby and many other languages. According to the DB-Engines ranking, Elasticsearch is the most popular enterprise search engine.
RocksDB is a high performance embedded database for key-value data. It is a fork of Google's LevelDB optimized to exploit multi-core processors (CPUs), and make efficient use of fast storage, such as solid-state drives (SSD), for input/output (I/O) bound workloads. It is based on a log-structured merge-tree data structure. It is written in C++ and provides official language bindings for C++, C, and Java. Many third-party language bindings exist. RocksDB is free and open-source software, released originally under a BSD 3-clause license. However, in July 2017 the project was migrated to a dual license of both Apache 2.0 and GPLv2 license. This change helped its adoption in Apache Software Foundation's projects after blacklist of the previous BSD+Patents license clause.
DBeaver is a SQL client software application and a database administration tool. For relational databases it uses the JDBC application programming interface (API) to interact with databases via a JDBC driver. For other databases (NoSQL) it uses proprietary database drivers. It provides an editor that supports code completion and syntax highlighting. It provides a plug-in architecture that allows users to modify much of the application's behavior to provide database-specific functionality or features that are database-independent. It is written in Java and based on the Eclipse platform.
The Server Side Public License (SSPL) is a source-available copyleft software license introduced by MongoDB Inc. in 2018.
Openverse is an open-source search engine for open content developed as part of the WordPress project. It searches Creative Commons licensed and public domain content from dozens of different sources. The software is licensed under the MIT License.
Valkey is an open-source in-memory storage, used as a distributed, in-memory key–value database, cache and message broker, with optional durability. Because it holds all data in memory and because of its design, Valkey offers low-latency reads and writes, making it particularly suitable for use cases that require a cache. Valkey is the successor to Redis, the most popular NoSQL database, and one of the most popular databases overall. Valkey or its predecessor Redis are used in companies like Twitter, Airbnb, Tinder, Yahoo, Adobe, Hulu, Amazon and OpenAI.
Some companies have only a single version of their software, while others follow an "open core" model, providing a community release of the core version, and offering proprietary premium features using a commercial license.
It was one of the first commercial companies to champion a concept called "open core."
"We deliver a fully functional cloud with Eucalyptus software. You can download it on a GPL v3 license. But, additionally, we provide enterprise features only if you pay for them ... it's open core," he says.
To make money, Eucalyptus Systems uses an open-core business model, offering one version of the software free through an open-source license and selling a commercial version with support and additional features ...