Reference › Version matrix

Version matrix

Verified against the npm registry on 2026-08-02. The canonical copy lives in builder/versions.js, which is what the generator uses.

#Pick a row and use everything in it

The single most common cause of a proxy that installs cleanly and then does nothing is mixing generations. These are the two that work:

#Scramjet 2.x, current architecture

{
	"@mercuryworkshop/scramjet": "2.0.67-alpha.2",
	"@mercuryworkshop/scramjet-controller": "0.0.14",
	"@mercuryworkshop/scramjet-utils": "0.0.3",
	"@mercuryworkshop/libcurl-transport": "^2.0.5",
	"@mercuryworkshop/epoxy-transport": "^3.0.1",
	"@mercuryworkshop/wisp-js": "^0.4.1"
}

Or let @mercuryworkshop/proxy-bootstrap@0.0.5 fetch all of it at runtime.

#Ultraviolet 3.x. For hosts that cannot hold a WebSocket

{
	"@titaniumnetwork-dev/ultraviolet": "^3.2.10",
	"@mercuryworkshop/bare-mux": "^2.1.9",
	"@mercuryworkshop/libcurl-transport": "^1.5.2",
	"@mercuryworkshop/epoxy-transport": "^2.1.28",
	"@mercuryworkshop/wisp-js": "^0.4.1",

	"@mercuryworkshop/bare-as-module3": "^2.2.5",
	"@tomphttp/bare-server-node": "^2.0.3"
}

The last two are only needed for a bare deployment.

#The trap: latest is not the newest Scramjet

npm install @mercuryworkshop/scramjet     # installs 1.1.0, not 2.x

Scramjet 2.x is published under the alpha dist-tag. latest still points at the 1.x line, which uses a completely different API ($scramjetLoadController and bare-mux). Ask for the version explicitly:

npm install @mercuryworkshop/scramjet@2.0.67-alpha.2

Pin the Scramjet packages exactly. These are alphas and the controller API has changed more than once between them.

Older guides install from a GitHub release URL:

https://github.com/MercuryWorkshop/scramjet/releases/download/latest/mercuryworkshop-scramjet-2.0.0-alpha.tgz

latest there is a rolling continuous build, so that URL no longer resolves to the version the guide was written against. Everything is on npm now; use npm.

#Transport compatibility

The interface these implement changed, and the package majors track it:

Mismatched versions sometimes appear to work, because the two interfaces are structurally similar. That is worse than failing outright, you get errors on specific sites rather than at startup.

#Node-side path helpers

Which packages export a helper for serving their browser assets:

For the ones without a helper:

import { createRequire } from "node:module";
import path from "node:path";

const require = createRequire(import.meta.url);
const dirOf = specifier => path.dirname(require.resolve(specifier));

app.use(
	"/controller/",
	express.static(dirOf("@mercuryworkshop/scramjet-controller"))
);
app.use(
	"/libcurl/",
	express.static(dirOf("@mercuryworkshop/libcurl-transport"))
);

require.resolve only resolves a path; it does not execute the module. That matters because the newer transports are browser-only and throw "environment detection error" if you import them in Node.

#What each package contains

The generated server gives each package a distinct prefix so the same routes work in Express and Fastify.

#Release timeline

Two things to read off this table: Ultraviolet has not shipped since October 2024 and is archived. And bare-mux 2.1.9 carries a deprecation notice pointing at proxy-transports, even though UV 3.x still depends on it.

#Checking for yourself

npm view @mercuryworkshop/scramjet dist-tags
npm view @mercuryworkshop/scramjet-controller version
npm view @mercuryworkshop/libcurl-transport versions --json | tail -20

If this page and npm disagree, npm is right and this page is stale. Please open a PR.

Source: docs/reference/versions.md