If you have been researching browser-based proxies, you have probably come across two names repeatedly: Holy Unblocker and Scramjet. At first glance they look like competing services, but they are quite different.
The simplest way to see it: Holy Unblocker was a web-proxy platform that used multiple proxy technologies, while Scramjet is a web-proxy technology that can be integrated into platforms such as Holy Unblocker.
In 2026 the distinction matters more, because the project formerly known as Holy Unblocker LTS continues as InvisiProxy LTS (we cover that in Holy Unblocker vs InvisiProxy). It includes Scramjet alongside Ultraviolet, Wisp, Bare-Mux and different transport systems.
What Was Holy Unblocker?
Holy Unblocker was an open-source, browser-based web proxy platform. It offered a clientless way to reach websites: instead of installing a conventional VPN app, traffic was processed through proxy technologies running inside the web application.
It was designed as a broader platform rather than a single engine, incorporating:
- Scramjet
- Ultraviolet
- Wisp
- Bare-Mux
- Rammerhead in earlier configurations
- Different transport systems
Its continuation, InvisiProxy LTS, lists Scramjet and Ultraviolet as its web proxies and Wisp, Bare-Mux, EpoxyTransport and LibcurlTransport as supporting components.
What Is Scramjet?
Scramjet is a web-proxy technology that intercepts, rewrites and sandboxes web content inside the browser. Its documentation calls it an experimental interception-based web proxy.
Holy Unblocker = the platform. Scramjet = one of the engines used by the platform. That is why comparing them as identical products is misleading.
Holy Unblocker vs Scramjet at a Glance
| Feature | Holy Unblocker | Scramjet |
|---|---|---|
| Type | Web-proxy platform | Web-proxy technology |
| Main purpose | A complete browser proxy experience | Process and proxy websites |
| Uses Scramjet | Yes | N/A |
| Uses Ultraviolet | Yes | No |
| Uses Wisp | Yes | Works with Wisp-based infrastructure |
| Browser-based / Open source / Self-hosting | Yes | Yes |
| Multiple proxy engines | Yes | No |
| Transport options | Multiple | Integrates with transport infrastructure |
| Current relationship | Continued as InvisiProxy LTS | Core proxy technology in InvisiProxy |
The biggest difference is scope. Holy Unblocker was a complete project, while Scramjet is a component that projects like it can use.
How Are They Connected?
The InvisiProxy repository, which identifies itself as formerly Holy Unblocker LTS, says the project is hosted locally with Scramjet and Ultraviolet built in. It names both as its web proxies, with Wisp and Bare-Mux providing supporting proxy and transport functionality. So Scramjet is not a rival website. It is part of the stack powering a Holy Unblocker-derived platform.
Why Did Holy Unblocker Use Scramjet?
Modern websites are far more than simple HTML. They may rely on:
- JavaScript and APIs
- WebSockets
- Dynamic URLs and cookies
- Cross-origin requests
- Service workers
- Embedded resources and browser storage
A simple URL-forwarding proxy often can't keep such sites working. Scramjet works inside the browser using interception, rewriting and sandboxing, which lets proxy applications handle complicated sites that traditional proxies cannot.
Why Scramjet Became Central
The v6.9.8 release described Scramjet as the main proxy for the project and added Libcurl and Epoxy transport support for Scramjet and Wisp. It also adapted apps such as Reddit, YouTube and Discord to use Scramjet. The project increasingly built its experience around it rather than treating it as an optional component.
What changed in the v7 era
InvisiProxy v7.0.0 updated Scramjet to v2.0.67-alpha and moved to scramjetFrame, along with changes to tooling and transport infrastructure. v7.0.1 updated Scramjet to v2.0.67-alpha.2 to address regressions and also fixed Ultraviolet regressions.
Is Scramjet the New Holy Unblocker?
No, and this is one of the most common misunderstandings. Scramjet did not replace Holy Unblocker. It is a proxy technology used within the Holy Unblocker LTS lineage.
Is Scramjet Better Than Holy Unblocker?
That is like asking whether a car engine is better than the car. Technical comparisons make sense between engines, for example Scramjet vs Ultraviolet, Scramjet vs Rammerhead, or Scramjet vs traditional web proxies. Comparing it with the whole platform mixes two levels of technology.
Scramjet vs Ultraviolet
This is the more direct comparison. Scramjet is interception-based, built around rewriting, sandboxing and browser integration. Ultraviolet is another browser-based proxy from TitaniumNetwork, described as using service workers, and it names Scramjet as its successor.
InvisiProxy still includes both, and its Ultraviolet page describes Ultraviolet as a fallback when Scramjet doesn't support a site. That is the practical reason to ship more than one engine: different websites behave differently depending on the proxy technology used, and the setup is more flexible than relying on a single implementation.
The Layers: Wisp, Epoxy and Libcurl
Wisp is not a user-facing website. It is part of the communication infrastructure the proxies use, and Bare-Mux lets the transport be switched. The layers stack like this:
Epoxy is described as optimized for Chromium and Apple environments, while Libcurl is a cross-browser option. These are transport mechanisms, not replacements for Scramjet. Scramjet handles browser-side proxying and rewriting, Wisp supplies protocol infrastructure, Epoxy or Libcurl handle transport, and InvisiProxy provides the user-facing platform. See how a request flows through the proxy on the homepage.
Does Holy Unblocker Still Use Scramjet in 2026?
The original name is no longer the main name of the LTS project, but its continuation, InvisiProxy LTS, does use Scramjet. The repository says Scramjet is built in, and the v7 releases include Scramjet updates.
Does Scramjet Work by Itself?
Yes. It is an open-source project that can run independently, with official instructions for building and running it locally. It is a reusable engine other projects can integrate, whereas Holy Unblocker was a broader application assembled from several technologies.
Which One Should Developers Use?
- A complete proxy platform: InvisiProxy gives you the interface, configuration, proxy selection, transports and supporting infrastructure.
- A proxy engine: Scramjet is more relevant if you want to integrate one into your own project.
- Learning the architecture: study Scramjet, Wisp, Bare-Mux and the transport layer separately.
The InvisiProxy repository also documents self-hosting and configuration for developers.
Speed and Compatibility
There is no meaningful single speed comparison, because Holy Unblocker (InvisiProxy) can use Scramjet. Performance depends on transport, server location, network latency, website complexity, browser, configuration, Scramjet version and server resources.
Compatibility depends on the website too. That is exactly why InvisiProxy includes both Scramjet and Ultraviolet, with Ultraviolet as a fallback when Scramjet can't handle a site.
What About Privacy?
Neither Scramjet nor Holy Unblocker is automatically anonymous or private just because it runs in a browser. Privacy depends on deployment, the proxy server, configuration and the site being accessed. InvisiProxy includes privacy-oriented features such as hidden history and Tor routing, but be careful with sensitive accounts and credentials on public instances, and understand what remains visible to the proxy operator or destination site. See our disclaimer for more.
Final Verdict
Holy Unblocker and Scramjet are not direct alternatives. Holy Unblocker was a complete browser-based proxy platform that combined multiple technologies, and its LTS continuation is now InvisiProxy LTS. Scramjet is an independent open-source technology focused on interception, rewriting and sandboxing, and it remains one of InvisiProxy's main proxy engines.
Holy Unblocker was the platform. Scramjet is one of the engines behind the platform. As browser proxy technology evolves, Scramjet, Ultraviolet, Wisp and modern transports will remain important parts of the ecosystem.
Frequently Asked Questions
Is Holy Unblocker the same as Scramjet?
No. Holy Unblocker was a broader web-proxy platform, while Scramjet is a web-proxy technology. Its LTS continuation, InvisiProxy, includes Scramjet.
Does Holy Unblocker use Scramjet?
Yes. The current InvisiProxy project, formerly Holy Unblocker LTS, includes Scramjet as one of its web proxies.
Is Scramjet the replacement for Holy Unblocker?
No. Holy Unblocker LTS continued as InvisiProxy LTS, while Scramjet remains one of the proxy technologies the project uses.
What replaced Holy Unblocker?
The LTS project formerly known as Holy Unblocker LTS is now InvisiProxy LTS.
Is Scramjet better than Ultraviolet?
Neither is universally better. They take different technical approaches and can differ in compatibility. InvisiProxy supports both, with Ultraviolet as a fallback where Scramjet may not work.
Can Scramjet be self-hosted?
Yes. Scramjet provides local run instructions, and InvisiProxy can also be self-hosted with Scramjet included.