What Is Open Source and Why Does It Matter for Software and Blockchain?

What Is Open Source?

Open source means that the source code of software is available and that a license gives others clear rights to use, view, modify, and distribute that code. Source code is the readable version of a program that developers work with. You can think of it as the recipe behind an app or program.

So just putting code online is not enough. Without the right license, it is not automatically clear whether you are allowed to copy, change, or share that code again. That license is what determines what is and is not allowed.

Open source also does not necessarily mean free. Someone can sell open-source software or charge money for distributing it, as long as the license allows it. It is mainly about freedom around the code, not the price.

A real open-source license may, for example, not make a distinction between users, groups, or uses. So you cannot make software available only to a certain group or only for private use and then call it open source. The terms also cannot depend on one specific technology.

Example: Suppose a developer releases a program under an open-source license. You are allowed to study the code, make your own version, and share it, as long as you follow the terms of that license. If the same code is posted online without a license, you do not automatically have those rights.

Key Takeaways

• Open source is about source code and the rights a license gives.
• You can often use, study, modify, and share open-source software.
• Open source does not automatically mean software is free.
• A license determines which terms apply to use and distribution.
• Public source code without the right license does not give others clear usage rights.

How Does Open-Source Software Work?

Open-source software works because the creator publishes the source code under a license with clear rules. Other developers can then copy, view, and modify the code. Whether they are also allowed to distribute their modified version depends on the license terms.

Many projects use version control. That is a system that keeps track of which change was made, by whom, and when. Such a saved change is called a commit. That way, you can usually see step by step how software has developed.

A common way of working together looks roughly like this:

1. Create your own working version
   A developer works in a branch, a separate line of work within the same project. Sometimes that person first makes a fork: their own copy of the entire project.

2. Change the code
   In that own version, someone can fix a bug, add a feature, or improve the code without changing the official version right away.

3. Submit a pull request
   A pull request is a proposal to include the change in the original project. Other developers can then review, discuss, and test the code.

4. Review the change
   Projects can have changes reviewed, automatically test whether the code works properly, and check for possible bugs or security issues.

5. Merge or not
   If the people with the right permissions agree, they can merge the change into the official version. This is often called merging.

A fork never has to go back into the original project. Someone can keep building independently on that own copy. Only when the maintainers of the original project accept the change does it become part of the official version.

GitHub, pull requests, and forks are useful and widely used ways to collaborate, but they are not a requirement for open source. The license is the foundation.

Who Manages Open-Source Software and How Are Changes Made?

Open-source software does not have one general manager; each project decides for itself who manages the code and how changes are accepted. That can be individual maintainers, but also an organization, foundation, or project community.

A maintainer is someone who helps keep the project running. That person can, for example, review changes, release new versions, and decide who gets access to the official repository. A repository is the place where a project’s code and change history are stored.

External developers can usually report a problem, suggest an improvement, or submit modified code. On platforms like GitHub, that happens through an issue or pull request, for example. An issue is often a report of a bug, question, or improvement idea.

Projects can set extra rules before code may be merged. Think of required reviews by other developers, automatic tests, or rules that prevent important code from being changed directly without approval.

With blockchain, there is another important point: adding new code to the official project does not automatically mean the blockchain rules change too.

A node is a computer that runs the software and checks transactions and blocks according to a blockchain’s rules.

For Bitcoin, BIPs serve as public proposals for improvements. For Ethereum, EIPs play a similar role for standards and changes to the network. Such a proposal can include explanations, feedback, and earlier revisions. But publishing a BIP or EIP does not automatically change the rules of Bitcoin or Ethereum.

Merging code does not do that automatically either. For a real change to the protocol rules, the technical rules of the network, the relevant participants must eventually run software that follows the same new rules.

In Bitcoin, no formal or informal body decides on its own whether BIPs are adopted. In Ethereum, EIP editors mainly handle administrative and editorial tasks, not the substantive decision about whether a proposal is wanted.

What Open-Source Licenses Exist?

Two common types are permissive licenses and copyleft licenses. Permissive licenses are called that because they allow a lot: you can usually use, modify, and redistribute the code freely. Copyleft is a play on the word copyright. With those licenses, you can also modify and share the code, but derivative software often has to remain available under the same open terms.

Here are some well-known licenses:

• MIT
  This is a permissive license. You may use, copy, modify, distribute, and even use the software commercially. You do have to include the copyright notice and license text. The software is provided without warranty and with limited liability.

• BSD-2-Clause and BSD-3-Clause
  These are also permissive licenses. They allow broad reuse and distribution, usually as long as the copyright and license information is kept intact.

• Apache-2.0
  Apache License 2.0 is also permissive. In addition, this license includes agreements about patents from people who contribute code to the project.

• GPL-3.0-only
  GPL is a copyleft license. Simply put, this license tries to make sure that the freedom to share and modify code is preserved when software is redistributed. Anyone who distributes software under GPLv3 must, under certain conditions, also make the corresponding source code available.

• MPL-2.0
  The Mozilla Public License 2.0 is a form of copyleft that mainly looks at individual files. If you modify a file covered by MPL, that changed file usually has to remain available under the same open terms. Other files in a larger project can still be under different terms.

Important to know: labels like permissive, strong copyleft, and weak copyleft are useful as a first explanation, but the exact terms are always in the license text. Especially when different software components with different licenses come together, things can get complicated.

Why Is Open Source Important for Crypto and Blockchain?

Open source is important for crypto and blockchain because nodes run software that checks transactions and blocks based on fixed rules. So if you run your own node, you may want to verify exactly which rules that software is carrying out.

For Bitcoin, Bitcoin Core is a well-known example. The source code is publicly available, and the software is distributed under the MIT license. That means developers and other interested people can study the code, propose contributions, or build their own version within the terms of that license.

Ethereum can be used with multiple different open-source programs, which are called clients. This software processes transactions, among other things, and helps computers take part in the Ethereum network. The different clients are built by different teams and sometimes use different programming languages.

Why is that useful? If a network depended entirely on one piece of software, a serious bug in it could affect many participants at once. Multiple independent clients make the network less dependent on one version of the software.

Of course, those different Ethereum clients still have to follow the same relevant specifications. Specifications are the shared technical agreements about how the network works. Think of rules for transactions, blocks, and the way the network reaches agreement on which data is valid.

BIPs and EIPs also help with public coordination. They make proposals, technical explanations, feedback, and revisions visible. That is valuable in crypto, because changes to the rules can have major consequences for everyone who runs software, stores crypto, or uses applications like smart contracts.

Open source also makes independent versions and forks possible. That gives developers and users more choice. But open code alone is not a guarantee that a blockchain is secure, decentralized, or widely used. The code has to be good, run correctly, and ultimately also be used by nodes and other participants.

What Are the Benefits of Open Source?

The biggest benefit of open source is that users can not only use software, but also inspect, modify, and share it. That is useful when an organization wants software to fit its own technical or operational needs.

Public code also makes review possible. You can look at changes in the version history and see what was adjusted. In a pull-request workflow, others can discuss a change before it is merged. Automatic tests and security checks can help find bugs earlier.

Open source can also make collaboration easier. Developers can reuse existing components instead of building everything from scratch. Of course, that is only allowed if the licenses are compatible and everyone follows the terms.

A fork offers another benefit: continuity. Suppose a group of developers wants a different technical direction than the original maintainers. Then they can continue with their own copy. That way, a project does not necessarily have to stop because there is disagreement about the future.

In blockchain, client diversity is a benefit. That means there are multiple different clients: programs that let computers participate in something like Ethereum. If these clients are built by different teams, the network is less dependent on one version of the software. That lowers the chance that one bug will affect all nodes, the computers that keep the network running, in the same way right away.

One important note: being able to inspect code does not mean experts have actually reviewed that code thoroughly. Open source makes review possible, but it is not proof that every bug has already been found or fixed.

What Risks and Limitations Does Open Source Have?

Open source is not a security certificate. Public code can still contain programming mistakes, vulnerabilities, or unsafe design choices. Just because everyone can look at the code does not mean enough experts have actually done so.

Maintenance is an important risk. Software usually needs ongoing maintenance, for example for bugs, security updates, and new dependencies. A dependency is an external software component that a program relies on. If a project is not maintained well, known problems can remain unresolved.

The more external software components a program uses, the more places there can be where a security problem can arise. A harmful or compromised dependency can therefore put an entire system at risk. That is why it is smart to check whether each dependency is really needed, where it comes from, and whether the version being used is still current.

Licenses also matter in open-source software. If you combine components with different licenses, there may be terms around making source code available, copyright notices, changes, or patents. That is especially something to look into carefully before software is distributed.

Forks also have a downside. They give freedom of choice, but they can split developers, users, documentation, and security maintenance across multiple projects. A fork needs its own maintainers, security, new versions, and users or node operators to keep working well over the long term.

For crypto, there is another checkpoint. The code in a public repository does not automatically have to be exactly the same as the software you install. That is why it is important to check where the software comes from and whether the version you install matches the official version.

For smart contracts, you can also check whether the published code matches the contract that actually runs on the blockchain.

In short: open source gives you more ways to verify things, but it does not do all the checking for you. So when it comes to software and crypto projects, also look at maintenance, security practices, dependencies, and the version you are actually using.

Conclusion

Open source means that source code is available under a license that gives clear rights to use, study, modify, and share the software. The license is at least as important as the code itself.

For crypto and blockchain, open source is extra relevant because nodes carry out protocol rules and different independent clients can make a network less dependent on one piece of software. At the same time, public code is not a guarantee of security or quality. Good reviews, active maintenance, and safe dependencies remain just as important.

So think of open source mainly as a strong foundation for transparency, collaboration, and choice. It creates possibilities, but you still need to look at how a project is managed and whether the software being used is maintained reliably.