diff --git a/packages/core/dist-link.js b/packages/core/dist-link.js
deleted file mode 100644
index d1e9c27..0000000
--- a/packages/core/dist-link.js
+++ /dev/null
@@ -1,16 +0,0 @@
-import * as fs from 'fs';
-
-const pkg = JSON.parse(fs.readFileSync('./package.json', 'utf-8'));
-
-for (let f of fs.readdirSync('dist')) {
-  const prefix = `syndicate-${pkg.version}`;
-  if (f.startsWith(prefix)) {
-    const linkname = `dist/syndicate${f.substring(prefix.length)}`;
-    try {
-      fs.unlinkSync(linkname);
-    } catch (e) {
-      if (e.code !== 'ENOENT') throw e;
-    }
-    fs.symlinkSync(f, linkname);
-  }
-}
diff --git a/packages/core/examples/box-and-client.js b/packages/core/examples/box-and-client.js
index 537f62f..8e700ba 100755
--- a/packages/core/examples/box-and-client.js
+++ b/packages/core/examples/box-and-client.js
@@ -1,4 +1,4 @@
-#!/usr/bin/env -S node --es-module-specifier-resolution=node
+#!/usr/bin/env node
 //---------------------------------------------------------------------------
 // @syndicate-lang/core, an implementation of Syndicate dataspaces for JS.
 // Copyright (C) 2016-2021 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
@@ -17,7 +17,7 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 //---------------------------------------------------------------------------
 
-import { Dataspace, Skeleton, Ground, Record, Discard, Capture, Observe } from '../lib/index';
+const { Dataspace, Skeleton, Ground, Record, Discard, Capture, Observe } = require('../dist/syndicate.js');
 const __ = Discard._instance;
 const _$ = Capture(__);
 
@@ -28,7 +28,7 @@ const N = 100000;
 
 console.time('box-and-client-' + N.toString());
 
-export function boot(thisFacet) {
+function boot(thisFacet) {
   thisFacet.spawn('box', function (thisFacet) {
     thisFacet.declareField(this, 'value', 0);
     thisFacet.addEndpoint(() => {
@@ -87,4 +87,6 @@ export function boot(thisFacet) {
     console.timeEnd('box-and-client-' + N.toString()));
 }
 
+module.exports.boot = boot;
+
 new Ground(boot).start();
diff --git a/packages/core/package.json b/packages/core/package.json
index 50d5653..38c566b 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -11,12 +11,12 @@
   "scripts": {
     "prepare": "npm run compile && npm run rollup",
     "compile": "../../node_modules/.bin/tsc --incremental",
-    "rollup": "../../node_modules/.bin/rollup -c syndicate.dist.js && node ./dist-link.js",
+    "rollup": "../../node_modules/.bin/rollup -c",
     "test": "../../node_modules/.bin/jest",
     "cover": "../../node_modules/.bin/nyc --reporter=html ../../node_modules/.bin/jest"
   },
-  "type": "module",
-  "main": "lib/index.js",
+  "main": "dist/syndicate.js",
+  "module": "lib/index.js",
   "types": "lib/index.d.ts",
   "author": "Tony Garnock-Jones <tonyg@leastfixedpoint.com>",
   "dependencies": {
diff --git a/packages/core/rollup.config.js b/packages/core/rollup.config.js
new file mode 100644
index 0000000..8084a2d
--- /dev/null
+++ b/packages/core/rollup.config.js
@@ -0,0 +1,54 @@
+import resolve from '@rollup/plugin-node-resolve';
+import { terser } from 'rollup-plugin-terser';
+
+function distfile(insertion) {
+  const f = `syndicate${insertion}.js`;
+  return `dist/${f}`;
+}
+
+function umd(insertion, extra) {
+  return {
+    file: distfile(insertion),
+    format: 'umd',
+    name: 'Syndicate',
+    globals: {
+      'crypto': 'crypto',
+    },
+    ... (extra || {})
+  };
+}
+
+function es6(insertion, extra) {
+  return {
+    file: distfile('.es6' + insertion),
+    format: 'es',
+    ... (extra || {})
+  };
+}
+
+export default [
+  {
+    input: 'lib/index.js',
+    plugins: [
+      resolve({
+        preferBuiltins: false,
+      }),
+    ],
+    output: [
+      umd(''),
+      umd('.min', { plugins: [terser()] }),
+    ],
+  }, {
+    input: 'lib/index.js',
+    plugins: [
+      resolve({
+        moduleDirectories: ['stubs', 'node_modules'],
+        preferBuiltins: false,
+      }),
+    ],
+    output: [
+      es6(''),
+      es6('.min', { plugins: [terser()] }),
+    ],
+  }
+];
diff --git a/packages/core/src/compiler/main.ts b/packages/core/src/compiler/main.ts
index 076946f..94c9ecd 100644
--- a/packages/core/src/compiler/main.ts
+++ b/packages/core/src/compiler/main.ts
@@ -1,4 +1,4 @@
-import fs from 'fs';
+import * as fs from 'fs';
 import * as S from '../syntax/index.js';
 import { Substitution } from '../syntax/index.js';
 import * as G from './grammar.js';
diff --git a/packages/core/src/runtime/randomid.ts b/packages/core/src/runtime/randomid.ts
index c09e5f0..f202813 100644
--- a/packages/core/src/runtime/randomid.ts
+++ b/packages/core/src/runtime/randomid.ts
@@ -27,17 +27,22 @@ export function _btoa(s: string): string {
     }
 }
 
-export function randomId(byteCount: number, hexOutput: boolean = false): string {
-    let buf: Uint8Array;
-    if (node_crypto.randomBytes !== void 0) {
-        buf = node_crypto.randomBytes(byteCount);
-    } else {
-        buf = new Uint8Array(byteCount);
-        crypto.getRandomValues(buf);
-    }
+function _finish(hexOutput: boolean, buf: Uint8Array): string {
     if (hexOutput) {
         return Bytes.from(buf).toHex();
     } else {
         return _btoa(String.fromCharCode.apply(null, buf as unknown as number[])).replace(/=/g,'');
     }
 }
+
+export const randomId =
+    (typeof crypto !== 'undefined' && 'getRandomValues' in crypto)
+    ? ((byteCount: number, hexOutput: boolean = false): string => {
+        const buf = new Uint8Array(byteCount);
+        crypto.getRandomValues(buf);
+        return _finish(hexOutput, buf);
+    })
+    : ((byteCount: number, hexOutput: boolean = false): string => {
+        let buf = node_crypto.randomBytes(byteCount);
+        return _finish(hexOutput, buf);
+    });
diff --git a/packages/core/syndicate.dist.js b/packages/core/syndicate.dist.js
deleted file mode 100644
index 641b517..0000000
--- a/packages/core/syndicate.dist.js
+++ /dev/null
@@ -1,41 +0,0 @@
-import pkg from './package.json';
-import resolve from '@rollup/plugin-node-resolve';
-import { terser } from 'rollup-plugin-terser';
-
-function distfile(insertion) {
-  const f = `syndicate-${pkg.version}${insertion}.js`;
-  return `dist/${f}`;
-}
-
-function umd(insertion, extra) {
-  return {
-    file: distfile(insertion),
-    format: 'umd',
-    name: 'Syndicate',
-    ... (extra || {})
-  };
-}
-
-function es6(insertion, extra) {
-  return {
-    file: distfile('.es6' + insertion),
-    format: 'es',
-    ... (extra || {})
-  };
-}
-
-export default {
-  input: 'lib/index.js',
-  plugins: [
-    resolve({
-      moduleDirectories: ['stubs', 'node_modules'],
-      preferBuiltins: false,
-    }),
-  ],
-  output: [
-    umd(''),
-    umd('.min', { plugins: [terser()] }),
-    es6(''),
-    es6('.min', { plugins: [terser()] }),
-  ],
-}