Open-source VPN apps give you something closed-source software cannot offer as easily: the ability for security researchers and technically experienced users to inspect the code. That does not automatically make a VPN private or secure, but it adds an important layer of transparency. Mullvad, Proton VPN and Private Internet Access all publish source code for their VPN apps while taking different approaches to privacy, pricing and features. The best open-source VPN for you depends on how much you value anonymity, independent audits and everyday usability.
Fully open-source apps with multiple published third-party audits.
Open-source apps audited by SEC Consult, plus a genuinely free tier.
Open-source apps at a lower price than most privacy-focused competitors.
Open-source software makes its source code publicly available for inspection. Researchers can examine how the VPN app handles connections, encryption and privacy-related features instead of relying entirely on claims made by the provider.
This transparency is valuable, but open source alone is not proof of security. A VPN should also have a clear privacy policy, strong protocols and a history of addressing security issues. Independent audits add another layer of verification by allowing external specialists to examine specific security or privacy claims.
It is also important to distinguish between an open-source VPN protocol and open-source client apps. A provider using WireGuard does not automatically make its own applications open source.
Mullvad has built its service around reducing the personal information required to create and maintain an account. Its VPN applications are open source, allowing the software to be independently inspected.
The provider has also commissioned third-party security audits covering different parts of its infrastructure and applications. This combination of published code and external assessment makes Mullvad particularly relevant for users who prioritise transparency.
Mullvad keeps its pricing model relatively simple rather than relying heavily on long subscription discounts. It is a strong option for privacy-focused users, although people primarily interested in streaming or a large collection of extra features may prefer a different service.
Proton VPN also publishes the source code for its VPN applications and has used independent security audits to evaluate its software. Its privacy-focused background makes transparency an important part of the service.
One major difference is that Proton VPN offers both free and paid options. The free tier can be useful if you want basic VPN protection without committing to a subscription, although it has fewer options than the paid service.
Paid plans expand server access and functionality, making Proton VPN a more versatile option for users who want open-source apps alongside features intended for everyday browsing and broader VPN use.
Private Internet Access, commonly called PIA, also makes its VPN applications open source. The service is particularly suitable for users who want more control over connection settings rather than a minimal interface with few configuration options.
PIA supports established VPN protocols and provides settings that allow more experienced users to adjust how their connections behave. This flexibility can be useful if you want to balance performance and privacy according to your network.
Its broad feature set makes PIA different from Mullvad’s more privacy-minimalist approach. The better choice depends on whether you prioritise account privacy or configuration options.
Publishing source code improves transparency, but it should be one part of your evaluation. Look at independent audits, logging policies, company history and how clearly the provider explains its infrastructure.
Open-source code is most valuable when people actually review it and providers respond to discovered problems. A published repository that receives little scrutiny should not automatically be considered safer than every closed-source alternative.
Mullvad is a strong choice if account privacy and a straightforward service are your priorities. Proton VPN combines open-source apps with a free tier and a broader selection of features. Private Internet Access is better suited to users who value configuration and control.
The best open-source VPN should combine transparent software with credible privacy practices. Do not choose based on the open-source label alone. Audits, policies and the provider’s overall approach to handling user data matter just as much.
It lets independent researchers, not just the provider, verify that the app does what it claims and does not contain hidden tracking.
It is a meaningful signal, but it still matters whether the published code has actually been audited and whether the no-logs policy has separately been reviewed.
Not necessarily. Open-source apps let you review the client code; server-side claims like no-logs still rely on audits or trust in the provider.
No, open-sourcing the code doesn't affect performance either way.
No. Also consider independent audits, privacy policies, logging practices, security features and whether the service fits your everyday needs.