diff --git a/common.js b/common.js
index 1b4bc11..ae9b78a 100644
--- a/common.js
+++ b/common.js
@@ -98,6 +98,15 @@ function getImageOS() {
   return imageOS
 }
 
+export const supportedPlatforms = [
+  'ubuntu-18.04',
+  'ubuntu-20.04',
+  'macos-10.15',
+  'macos-11.0',
+  'windows-2019',
+  'windows-2022',
+]
+
 export function getVirtualEnvironmentName() {
   const imageOS = getImageOS()
 
diff --git a/dist/index.js b/dist/index.js
index 8ff2ee4..3a40693 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -259,6 +259,7 @@ __nccwpck_require__.r(__webpack_exports__);
 /* harmony export */   "isBundler2Default": () => (/* binding */ isBundler2Default),
 /* harmony export */   "floatVersion": () => (/* binding */ floatVersion),
 /* harmony export */   "hashFile": () => (/* binding */ hashFile),
+/* harmony export */   "supportedPlatforms": () => (/* binding */ supportedPlatforms),
 /* harmony export */   "getVirtualEnvironmentName": () => (/* binding */ getVirtualEnvironmentName),
 /* harmony export */   "shouldUseToolCache": () => (/* binding */ shouldUseToolCache),
 /* harmony export */   "getToolCacheRubyPrefix": () => (/* binding */ getToolCacheRubyPrefix),
@@ -366,6 +367,15 @@ function getImageOS() {
   return imageOS
 }
 
+const supportedPlatforms = [
+  'ubuntu-18.04',
+  'ubuntu-20.04',
+  'macos-10.15',
+  'macos-11.0',
+  'windows-2019',
+  'windows-2022',
+]
+
 function getVirtualEnvironmentName() {
   const imageOS = getImageOS()
 
@@ -59565,6 +59575,10 @@ const releasesURL = 'https://github.com/ruby/ruby-builder/releases'
 const windows = common.windows
 
 function getAvailableVersions(platform, engine) {
+  if (!common.supportedPlatforms.includes(platform)) {
+    throw new Error(`Unsupported platform ${platform}`)
+  }
+
   return rubyBuilderVersions[engine]
 }
 
@@ -59747,6 +59761,10 @@ const msysPathEntries = [`${msys1}\\mingw\\x86_64-w64-mingw32\\bin`, `${msys1}\\
 const virtualEnv = common.getVirtualEnvironmentName()
 
 function getAvailableVersions(platform, engine) {
+  if (!common.supportedPlatforms.includes(platform)) {
+    throw new Error(`Unsupported platform ${platform}`)
+  }
+
   if (engine === 'ruby') {
     return Object.keys(rubyInstallerVersions)
   } else {
@@ -60315,7 +60333,7 @@ async function setupRuby(options = {}) {
   const [engine, parsedVersion] = parseRubyEngineAndVersion(inputs['ruby-version'])
 
   let installer
-  if (platform.startsWith('windows-') && engine !== 'jruby') {
+  if (platform.startsWith('windows-') && engine === 'ruby') {
     installer = __nccwpck_require__(3216)
   } else {
     installer = __nccwpck_require__(9974)
diff --git a/index.js b/index.js
index b3c78e6..9dd98da 100644
--- a/index.js
+++ b/index.js
@@ -42,7 +42,7 @@ export async function setupRuby(options = {}) {
   const [engine, parsedVersion] = parseRubyEngineAndVersion(inputs['ruby-version'])
 
   let installer
-  if (platform.startsWith('windows-') && engine !== 'jruby') {
+  if (platform.startsWith('windows-') && engine === 'ruby') {
     installer = require('./windows')
   } else {
     installer = require('./ruby-builder')
diff --git a/ruby-builder.js b/ruby-builder.js
index 942cb1e..81ca2cd 100644
--- a/ruby-builder.js
+++ b/ruby-builder.js
@@ -13,6 +13,10 @@ const releasesURL = 'https://github.com/ruby/ruby-builder/releases'
 const windows = common.windows
 
 export function getAvailableVersions(platform, engine) {
+  if (!common.supportedPlatforms.includes(platform)) {
+    throw new Error(`Unsupported platform ${platform}`)
+  }
+
   return rubyBuilderVersions[engine]
 }
 
diff --git a/windows.js b/windows.js
index da9fd2b..36bcd1d 100644
--- a/windows.js
+++ b/windows.js
@@ -25,6 +25,10 @@ const msysPathEntries = [`${msys1}\\mingw\\x86_64-w64-mingw32\\bin`, `${msys1}\\
 const virtualEnv = common.getVirtualEnvironmentName()
 
 export function getAvailableVersions(platform, engine) {
+  if (!common.supportedPlatforms.includes(platform)) {
+    throw new Error(`Unsupported platform ${platform}`)
+  }
+
   if (engine === 'ruby') {
     return Object.keys(rubyInstallerVersions)
   } else {