What is open source software? A guide to transparent, secure technology

Open source refers to software whose source code is freely available to view, modify, and distribute. Unlike proprietary software (or closed-source), open source empowers users to inspect how tools are built, identify vulnerabilities, and adapt programs to meet their needs. It supports community-driven innovation and collaboration while promoting accountability.

Open source software is everywhere — from operating systems like Linux to privacy tools like Tor and newer decentralized VPNs (dVPNs). Understanding the value of open source is key for anyone interested in online security, digital freedom, or building better tech. This is especially important if you're looking for tools to protect your privacy online, like VPNs.

How open source software works and why it matters

Open source software is developed with public access to its codebase. Anyone can contribute, suggest changes, or build new features. A strong community reviews updates, catches bugs, and ensures quality control.

Key principles of open source:

• Publicly accessible source code
• Community-based development
• Transparent updates and version history
• Licensed for free use and redistribution

This model leads to greater trust and innovation. It is particularly critical in privacy tools like VPNs where security must be verifiable.

Open source vs. proprietary software: What’s the difference?

Open source software and proprietary software differ in several key areas:

• Code access: Open source software has fully accessible and modifiable code. Proprietary software is closed and owned by a specific vendor.

• Cost: Open source tools are usually free to use. Proprietary tools often require payment or a subscription.

• Transparency: Open source allows for public audits of its code. Proprietary software is often a black box.

• Customizability: Open source is easy to fork or customize. Proprietary options typically limit this.

• Community input: Open source thrives on active community input. Proprietary platforms rely on vendor-led updates.

In short, open source gives users more control.

Common uses for open source software

Open source software has become foundational in modern computing, not only because it's cost-effective, but also because it allows organizations to maintain full transparency over their infrastructure. Many governments and enterprises now require open-source standards for security compliance and interoperability.

Here are some ways it can be beneficial.

Privacy and security

This is one of the most vital use cases for open source. With public code, communities can verify that software doesn’t include backdoors, spyware, or unnecessary data collection. Open source is central to digital privacy. Transparent code lets experts verify that tools don’t collect or leak user data.

Some great examples of open source privacy software includes:

• Signal: Encrypted communication without metadata logging
• KeePassXC: Offline password manager with no tracking
• NymVPN: A decentralized VPN which protects both your contents and the metadata of your traffic

Operating systems

Open source operating systems provide a stable, customizable foundation for everything from cloud infrastructure to personal desktops and privacy-first mobile devices. Open source operating systems provide full control over updates, telemetry, and software installations.

Open source OSs include:

• Linux (Ubuntu, Debian): Widely used in servers and personal computing
• Tails OS: A secure, amnesic OS for privacy-sensitive tasks
• Android (AOSP): Mobile OS derived from open source foundations

Web browsers

Browsing the internet with open source tools gives users more control over data, cookies, and scripts — a key foundation for maintaining digital privacy and performance. Browsers and networking tools built on open source offer safer, customizable ways to access the internet.

Here are some privacy-focused, open source browsers trusted by the Nym team:

• Tor Browser: Protects browsing anonymity through a decentralized network
• Mullvad: Privacy-first browser with anti-tracking features
• Brave: Chromium-based browser with ad blocking and Tor tabs
• Librewolf: A fork of FireFox with a focus on privacy

Is open source software more secure than proprietary software?

There is nothing intrinsically more secure about open source software than proprietary software. What makes the difference is if there is a security vulnerability, it can be found by a community of auditors and not just hired specialists. This depends, in the end, on the level of resources dedicated to it. If open source software has little community engagement with the code base, then problems may go unnoticed. If a closed source code is not audit by independent professionals, then privacy-violating mechanisms can go unreported.

Transparency leads to more eyes on the code, but security depends on maintenance. Well-managed open source projects can be extremely secure. Poorly maintained ones may introduce risks. The key is therefore vetting projects with active communities and recent updates.

Choosing open source VPNs is particularly crucial

When you use a Virtual Private Network (VPN) to protect your privacy online, you're essentially giving a company access to all your data so they can protect it. But if the code of the VPN is proprietary and closed, there is no way for anyone to verify whether that company is not mishandling it, such as permitting backdoors on encryption, allowing third parties access to logging, or worse.

Fully open source code is thus an essential protection when you're looking for a VPN. It is for this reason that NymVPN is fully open source and independently audited. You can read our whole code base right here!

How to review open source code for privacy concerns

For those who want to contribute meaningfully, getting involved in code audits or user feedback forums can help developers identify overlooked security issues. Even testing usability or writing documentation can strengthen the privacy posture of a project. If you're technically inclined, reviewing source code can be a game changer. Look for:

• Clear, well-documented functions
• Minimal third-party tracking libraries
• Community-reviewed pull requests
• Encrypted data handling

Non-coders can still contribute by reporting bugs, funding development, or advocating for privacy-first defaults.

Open source is the foundation of an open and accessible Internet

Open source supports a free and fair internet. It enables accessibility by supporting multiple platforms and languages, and avoids paywalls that restrict essential tools. It’s especially valuable for users in censored or surveilled regions — letting them access secure tools without permission or corporate oversight.