diff --git a/.changeset/scan-jsx-all-environments.md b/.changeset/scan-jsx-all-environments.md
new file mode 100644
index 00000000..a5401034
--- /dev/null
+++ b/.changeset/scan-jsx-all-environments.md
@@ -0,0 +1,5 @@
+---
+'@solidjs/vite-plugin': patch
+---
+
+The dependency scanner settings now reach every environment, not just `client` (#387). Vite seeds only the `client` environment from the top-level `optimizeDeps`, so an `ssr` (or other server) environment with discovery turned back on — as `@cloudflare/vite-plugin` does for workerd SSR — scanned Solid TSX with Rolldown's default React automatic runtime. The scan failed on an unresolvable `react/jsx-dev-runtime` and pre-bundling was skipped for that environment, which showed up as duplicate Solid instances in the app. `configEnvironment` now gives non-client environments the classic scanner JSX runtime (unless the app set its own per-environment `transform.jsx`), the `.tsrx` extension, and the tsrx scan plugin.
diff --git a/examples/ssr/package.json b/examples/ssr/package.json
index facb405f..421f0c78 100644
--- a/examples/ssr/package.json
+++ b/examples/ssr/package.json
@@ -8,7 +8,7 @@
     "build:client": "vite build --outDir dist/client",
     "build:server": "vite build --ssr src/entry-server.tsx --outDir dist/server",
     "serve": "NODE_ENV=production node server.js",
-    "test": "node test/run.mjs && node test/boundary.mjs"
+    "test": "node test/run.mjs && node test/boundary.mjs && node test/scan.mjs"
   },
   "devDependencies": {
     "vite": "^8.2.1",
diff --git a/examples/ssr/test/scan.mjs b/examples/ssr/test/scan.mjs
new file mode 100644
index 00000000..d60dca40
--- /dev/null
+++ b/examples/ssr/test/scan.mjs
@@ -0,0 +1,121 @@
+// Dependency-scan test for non-client environments (#387). Vite seeds only
+// the `client` environment from the top-level `optimizeDeps`, so the scanner
+// JSX setting the plugin returns from `config` never reached `ssr`: with
+// discovery turned back on (as @cloudflare/vite-plugin does for workerd
+// SSR), Rolldown scanned Solid TSX with React's automatic runtime and the
+// scan failed on an unresolvable `react/jsx-dev-runtime`, skipping
+// pre-bundling for that environment. Asserts, in one process:
+//   - config: the ssr environment resolves the classic scanner JSX runtime,
+//     the `.tsrx` extension and the tsrx scan plugin; a per-environment
+//     `transform.jsx` set by the app is left alone,
+//   - scan: a cold dev server with ssr discovery on (entries
+//     src/entry-server.tsx, whose graph includes JSX and import.meta.glob)
+//     completes both the client and the ssr scans without a failure banner.
+//
+// Requires the plugin built (pnpm build at the repo root). No browser.
+// Usage: node test/scan.mjs
+
+import { fileURLToPath } from 'node:url';
+import { mkdtempSync, rmSync } from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { createServer, resolveConfig } from 'vite';
+
+const exampleDir = path.dirname(path.dirname(fileURLToPath(import.meta.url)));
+
+const results = [];
+function record(name, ok, detail = '') {
+  results.push({ name, ok, detail });
+  console.log(`  [scan] ${ok ? 'PASS' : 'FAIL'} ${name}${detail && !ok ? ` — ${detail}` : ''}`);
+}
+
+const ssrDiscovery = { noDiscovery: false, entries: ['src/entry-server.tsx'] };
+
+// ---- Resolved config -------------------------------------------------------
+{
+  const config = await resolveConfig(
+    { root: exampleDir, logLevel: 'silent', environments: { ssr: { optimizeDeps: ssrDiscovery } } },
+    'serve',
+  );
+  const ssr = config.environments.ssr.optimizeDeps;
+  record(
+    'ssr scanner uses the classic JSX runtime',
+    ssr.rolldownOptions?.transform?.jsx?.runtime === 'classic',
+    JSON.stringify(ssr.rolldownOptions?.transform),
+  );
+  record('ssr scanner crawls .tsrx', !!ssr.extensions?.includes('.tsrx'), JSON.stringify(ssr.extensions));
+  const plugins = [ssr.rolldownOptions?.plugins].flat(Infinity);
+  record(
+    'ssr scanner registers the tsrx scan plugin',
+    plugins.some((p) => p?.name === 'solid:tsrx-dep-scan'),
+  );
+  record(
+    'client scanner keeps the classic JSX runtime',
+    config.environments.client.optimizeDeps.rolldownOptions?.transform?.jsx?.runtime === 'classic',
+  );
+}
+{
+  const config = await resolveConfig(
+    {
+      root: exampleDir,
+      logLevel: 'silent',
+      environments: {
+        ssr: { optimizeDeps: { rolldownOptions: { transform: { jsx: { runtime: 'automatic' } } } } },
+      },
+    },
+    'serve',
+  );
+  record(
+    'an app-set per-environment scanner JSX option wins',
+    config.environments.ssr.optimizeDeps.rolldownOptions?.transform?.jsx?.runtime === 'automatic',
+  );
+}
+
+// ---- Cold scans ------------------------------------------------------------
+{
+  const cacheDir = mkdtempSync(path.join(os.tmpdir(), 'solid-ssr-scan-'));
+  const failed = {};
+  const server = await createServer({
+    root: exampleDir,
+    cacheDir,
+    logLevel: 'silent',
+    server: { port: 0 },
+    environments: { ssr: { optimizeDeps: ssrDiscovery } },
+  });
+  try {
+    for (const [name, env] of Object.entries(server.environments)) {
+      const error = env.logger.error;
+      env.logger = {
+        ...env.logger,
+        error(msg, opts) {
+          if (String(msg).includes('Failed to run dependency scan')) failed[name] = String(msg);
+          return error.call(this, msg, opts);
+        },
+      };
+    }
+    await server.listen();
+    for (const name of ['client', 'ssr']) {
+      const optimizer = server.environments[name]?.depsOptimizer;
+      if (!optimizer || optimizer.options.noDiscovery) {
+        record(`${name} scan ran`, false, 'discovery is off');
+        continue;
+      }
+      for (let i = 0; i < 100 && !optimizer.scanProcessing; i++) {
+        await new Promise((r) => setTimeout(r, 50));
+      }
+      await optimizer.scanProcessing;
+      record(`${name} scan completed (no failure banner)`, !failed[name], failed[name]?.slice(0, 300));
+    }
+  } finally {
+    await server.close();
+    rmSync(cacheDir, { recursive: true, force: true });
+  }
+}
+
+const failures = results.filter((r) => !r.ok);
+console.log(`\n${results.length - failures.length}/${results.length} scan assertions passed`);
+if (failures.length) {
+  console.log('\nFailures:');
+  for (const f of failures) console.log(`  ${f.name} — ${f.detail}`);
+}
+process.exit(failures.length ? 1 : 0);
diff --git a/src/index.ts b/src/index.ts
index 2fa1eab7..bf227ea3 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1179,6 +1179,28 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin[] {
   let projectRoot = process.cwd();
   let isTestMode = false;
   let serverTestPosture = false;
+
+  // Lets the dependency scanner crawl `.tsrx` imports. Registered on every
+  // environment's `optimizeDeps` (top-level for client, configEnvironment
+  // for the rest).
+  const tsrxDepScanPlugin = {
+    name: 'solid:tsrx-dep-scan',
+    async transform(source: string, id: string) {
+      if (!isTsrxModule(id) || isTsrxCssModule(id)) return null;
+      const compiler = await loadNativeCompiler();
+      const result = await compiler.transformAsync(source, {
+        ...getSolidOptions(options, false, replaceDev, observe, isTestMode),
+        filename: cleanModuleId(id),
+        sourceMap: false,
+      });
+      const stripped = await transformWithOxc(result.code, cleanModuleId(id) + '.tsx', {
+        lang: 'tsx',
+        sourcemap: false,
+        target: 'esnext',
+      });
+      return { code: stripped.code, map: null };
+    },
+  };
   let isBuild = false;
   let isSsrBuild = false;
   let base = '/';
@@ -1580,26 +1602,7 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin[] {
           // Keep Solid TSX from injecting React's automatic runtime during scanning.
           rolldownOptions: {
             transform: { jsx: { runtime: 'classic' as const } },
-            plugins: [
-              {
-                name: 'solid:tsrx-dep-scan',
-                async transform(source: string, id: string) {
-                  if (!isTsrxModule(id) || isTsrxCssModule(id)) return null;
-                  const compiler = await loadNativeCompiler();
-                  const result = await compiler.transformAsync(source, {
-                    ...getSolidOptions(options, false, replaceDev, observe, isTestMode),
-                    filename: cleanModuleId(id),
-                    sourceMap: false,
-                  });
-                  const stripped = await transformWithOxc(result.code, cleanModuleId(id) + '.tsx', {
-                    lang: 'tsx',
-                    sourcemap: false,
-                    target: 'esnext',
-                  });
-                  return { code: stripped.code, map: null };
-                },
-              },
-            ],
+            plugins: [tsrxDepScanPlugin],
           },
         },
         ...(Object.keys(test).length ? { test } : {}),
@@ -1633,6 +1636,25 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin[] {
         ...config.resolve.conditions,
       ];
 
+      // Vite seeds only the `client` environment from the top-level
+      // `optimizeDeps` set in `config`, so every other environment would
+      // scan Solid TSX with Rolldown's default (React's automatic runtime)
+      // and fail on an unresolvable `react/jsx-dev-runtime`. Server
+      // environments default to `noDiscovery: true`, but hosts that run SSR
+      // outside Node turn discovery back on (@cloudflare/vite-plugin), #387.
+      if (name !== 'client') {
+        const optimizeDeps = (config.optimizeDeps ??= {});
+        if (!optimizeDeps.extensions?.includes('.tsrx')) {
+          optimizeDeps.extensions = [...(optimizeDeps.extensions ?? []), '.tsrx'];
+        }
+        const rolldownOptions = (optimizeDeps.rolldownOptions ??= {});
+        const transform = (rolldownOptions.transform ??= {});
+        transform.jsx ??= { runtime: 'classic' };
+        rolldownOptions.plugins = rolldownOptions.plugins
+          ? [rolldownOptions.plugins, tsrxDepScanPlugin]
+          : [tsrxDepScanPlugin];
+      }
+
       // `resolve.conditions` above only governs modules Vite inlines.
       // Externalized server deps are resolved by `fetchModule` with
       // `resolve.externalConditions` (default `['node', 'module-sync']`) and