diff --git a/package-lock.json b/package-lock.json
index 2711e35..24998cf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19,7 +19,8 @@
         "chai": "^4.2.0",
         "eslint": "^8.0.1",
         "mocha": "^8.2.1",
-        "rollup": "^2.38.5"
+        "rollup": "^2.38.5",
+        "rollup-plugin-jscc": "^2.0.0"
       }
     },
     "node_modules/@eslint/eslintrc": {
@@ -71,6 +72,24 @@
       "integrity": "sha512-ZnQMnLV4e7hDlUvw8H+U8ASL02SS2Gn6+9Ac3wGGLIe7+je2AeAOxPY+izIPJDfFDb7eDjev0Us8MO1iFRN8hA==",
       "dev": true
     },
+    "node_modules/@jsbits/escape-regex-str": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@jsbits/escape-regex-str/-/escape-regex-str-1.0.3.tgz",
+      "integrity": "sha512-0800vYI2fg1nuUq/T9Tqv8DMOLLNiRAltxFbKIbR7szrvW6qTuI2+zGK51hV7NAAmUr4G83Kvpj2R6Yyg07iIw==",
+      "dev": true,
+      "engines": {
+        "node": ">=4.2"
+      }
+    },
+    "node_modules/@jsbits/get-package-version": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@jsbits/get-package-version/-/get-package-version-1.0.3.tgz",
+      "integrity": "sha512-IJy1jRL01x7p6UEpgKa1lVLstMUx8EiIR8pPoS5sBfsHEoeLkzYiNpAfxPx8zLDUJyS1yBbChJjcWdPqyH285w==",
+      "dev": true,
+      "engines": {
+        "node": ">=4.2"
+      }
+    },
     "node_modules/@ungap/promise-all-settled": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/@ungap/promise-all-settled/-/promise-all-settled-1.1.2.tgz",
@@ -668,6 +687,12 @@
         "node": ">=4.0"
       }
     },
+    "node_modules/estree-walker": {
+      "version": "0.6.1",
+      "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-0.6.1.tgz",
+      "integrity": "sha512-SqmZANLWS0mnatqbSfRP5g8OXZC12Fgg1IwNtLsyHDzJizORW4khDfjPqJZsemPWBB2uqykUah5YpQ6epsqC/w==",
+      "dev": true
+    },
     "node_modules/esutils": {
       "version": "2.0.3",
       "resolved": "https://registry.npmjs.org/esutils/-/esutils-2.0.3.tgz",
@@ -1009,6 +1034,22 @@
         "js-yaml": "bin/js-yaml.js"
       }
     },
+    "node_modules/jscc": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/jscc/-/jscc-1.1.1.tgz",
+      "integrity": "sha512-anpZkTXwZbxfxLEBMciKxXMHx2xOLK2qhynIhTnoSyC+wGOEPrAoofxnADgblbarn0kijVMt1U71cQGmRF/1Og==",
+      "dev": true,
+      "dependencies": {
+        "@jsbits/escape-regex-str": "^1.0.2",
+        "@jsbits/get-package-version": "^1.0.2",
+        "magic-string": "^0.25.1",
+        "perf-regexes": "^1.0.1",
+        "skip-regex": "^1.0.2"
+      },
+      "engines": {
+        "node": ">=6.0"
+      }
+    },
     "node_modules/json-schema-traverse": {
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-0.4.1.tgz",
@@ -1067,6 +1108,15 @@
         "node": ">=10"
       }
     },
+    "node_modules/magic-string": {
+      "version": "0.25.9",
+      "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.25.9.tgz",
+      "integrity": "sha512-RmF0AsMzgt25qzqqLc1+MbHmhdx0ojF2Fvs4XnOqz2ZOBXzzkEwc/dJQZCYHAn7v1jbVOjAZfK8msRn4BxO4VQ==",
+      "dev": true,
+      "dependencies": {
+        "sourcemap-codec": "^1.4.8"
+      }
+    },
     "node_modules/minimatch": {
       "version": "3.0.4",
       "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
@@ -1322,6 +1372,15 @@
         "node": "*"
       }
     },
+    "node_modules/perf-regexes": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/perf-regexes/-/perf-regexes-1.0.1.tgz",
+      "integrity": "sha512-L7MXxUDtqr4PUaLFCDCXBfGV/6KLIuSEccizDI7JxT+c9x1G1v04BQ4+4oag84SHaCdrBgQAIs/Cqn+flwFPng==",
+      "dev": true,
+      "engines": {
+        "node": ">=6.14"
+      }
+    },
     "node_modules/picomatch": {
       "version": "2.3.1",
       "resolved": "https://registry.npmjs.org/picomatch/-/picomatch-2.3.1.tgz",
@@ -1433,6 +1492,32 @@
         "fsevents": "~2.3.2"
       }
     },
+    "node_modules/rollup-plugin-jscc": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/rollup-plugin-jscc/-/rollup-plugin-jscc-2.0.0.tgz",
+      "integrity": "sha512-5jG9q79K2u5uRBTKA+GA4gqt1zA7qHQRpcabZMoVs913gr75s428O7K3r58n2vADDzwIhiOKMo7rCMhOyks6dw==",
+      "dev": true,
+      "dependencies": {
+        "@jsbits/get-package-version": "^1.0.3",
+        "jscc": "^1.1.1",
+        "rollup-pluginutils": "^2.8.2"
+      },
+      "engines": {
+        "node": ">=10.12.0"
+      },
+      "peerDependencies": {
+        "rollup": ">=2"
+      }
+    },
+    "node_modules/rollup-pluginutils": {
+      "version": "2.8.2",
+      "resolved": "https://registry.npmjs.org/rollup-pluginutils/-/rollup-pluginutils-2.8.2.tgz",
+      "integrity": "sha512-EEp9NhnUkwY8aif6bxgovPHMoMoNr2FulJziTndpt5H9RdwC47GSGuII9XxpSdzVGM0GWrNPHV6ie1LTNJPaLQ==",
+      "dev": true,
+      "dependencies": {
+        "estree-walker": "^0.6.1"
+      }
+    },
     "node_modules/safe-buffer": {
       "version": "5.2.1",
       "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz",
@@ -1483,6 +1568,21 @@
         "node": ">=8"
       }
     },
+    "node_modules/skip-regex": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/skip-regex/-/skip-regex-1.0.2.tgz",
+      "integrity": "sha512-pEjMUbwJ5Pl/6Vn6FsamXHXItJXSRftcibixDmNCWbWhic0hzHrwkMZo0IZ7fMRH9KxcWDFSkzhccB4285PutA==",
+      "dev": true,
+      "engines": {
+        "node": ">=4.2"
+      }
+    },
+    "node_modules/sourcemap-codec": {
+      "version": "1.4.8",
+      "resolved": "https://registry.npmjs.org/sourcemap-codec/-/sourcemap-codec-1.4.8.tgz",
+      "integrity": "sha512-9NykojV5Uih4lgo5So5dtw+f0JgJX30KCNI8gwhz2J9A15wD0Ml6tjHKwf6fTSa6fAdVBdZeNOs9eJ71qCk8vA==",
+      "dev": true
+    },
     "node_modules/string-width": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/string-width/-/string-width-2.1.1.tgz",
@@ -1856,6 +1956,18 @@
       "integrity": "sha512-ZnQMnLV4e7hDlUvw8H+U8ASL02SS2Gn6+9Ac3wGGLIe7+je2AeAOxPY+izIPJDfFDb7eDjev0Us8MO1iFRN8hA==",
       "dev": true
     },
+    "@jsbits/escape-regex-str": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@jsbits/escape-regex-str/-/escape-regex-str-1.0.3.tgz",
+      "integrity": "sha512-0800vYI2fg1nuUq/T9Tqv8DMOLLNiRAltxFbKIbR7szrvW6qTuI2+zGK51hV7NAAmUr4G83Kvpj2R6Yyg07iIw==",
+      "dev": true
+    },
+    "@jsbits/get-package-version": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@jsbits/get-package-version/-/get-package-version-1.0.3.tgz",
+      "integrity": "sha512-IJy1jRL01x7p6UEpgKa1lVLstMUx8EiIR8pPoS5sBfsHEoeLkzYiNpAfxPx8zLDUJyS1yBbChJjcWdPqyH285w==",
+      "dev": true
+    },
     "@ungap/promise-all-settled": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/@ungap/promise-all-settled/-/promise-all-settled-1.1.2.tgz",
@@ -2308,6 +2420,12 @@
       "integrity": "sha512-MMdARuVEQziNTeJD8DgMqmhwR11BRQ/cBP+pLtYdSTnf3MIO8fFeiINEbX36ZdNlfU/7A9f3gUw49B3oQsvwBA==",
       "dev": true
     },
+    "estree-walker": {
+      "version": "0.6.1",
+      "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-0.6.1.tgz",
+      "integrity": "sha512-SqmZANLWS0mnatqbSfRP5g8OXZC12Fgg1IwNtLsyHDzJizORW4khDfjPqJZsemPWBB2uqykUah5YpQ6epsqC/w==",
+      "dev": true
+    },
     "esutils": {
       "version": "2.0.3",
       "resolved": "https://registry.npmjs.org/esutils/-/esutils-2.0.3.tgz",
@@ -2558,6 +2676,19 @@
         "argparse": "^2.0.1"
       }
     },
+    "jscc": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/jscc/-/jscc-1.1.1.tgz",
+      "integrity": "sha512-anpZkTXwZbxfxLEBMciKxXMHx2xOLK2qhynIhTnoSyC+wGOEPrAoofxnADgblbarn0kijVMt1U71cQGmRF/1Og==",
+      "dev": true,
+      "requires": {
+        "@jsbits/escape-regex-str": "^1.0.2",
+        "@jsbits/get-package-version": "^1.0.2",
+        "magic-string": "^0.25.1",
+        "perf-regexes": "^1.0.1",
+        "skip-regex": "^1.0.2"
+      }
+    },
     "json-schema-traverse": {
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-0.4.1.tgz",
@@ -2604,6 +2735,15 @@
         "chalk": "^4.0.0"
       }
     },
+    "magic-string": {
+      "version": "0.25.9",
+      "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.25.9.tgz",
+      "integrity": "sha512-RmF0AsMzgt25qzqqLc1+MbHmhdx0ojF2Fvs4XnOqz2ZOBXzzkEwc/dJQZCYHAn7v1jbVOjAZfK8msRn4BxO4VQ==",
+      "dev": true,
+      "requires": {
+        "sourcemap-codec": "^1.4.8"
+      }
+    },
     "minimatch": {
       "version": "3.0.4",
       "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
@@ -2793,6 +2933,12 @@
       "integrity": "sha512-Dp6zGqpTdETdR63lehJYPeIOqpiNBNtc7BpWSLrOje7UaIsE5aY92r/AunQA7rsXvet3lrJ3JnZX29UPTKXyKQ==",
       "dev": true
     },
+    "perf-regexes": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/perf-regexes/-/perf-regexes-1.0.1.tgz",
+      "integrity": "sha512-L7MXxUDtqr4PUaLFCDCXBfGV/6KLIuSEccizDI7JxT+c9x1G1v04BQ4+4oag84SHaCdrBgQAIs/Cqn+flwFPng==",
+      "dev": true
+    },
     "picomatch": {
       "version": "2.3.1",
       "resolved": "https://registry.npmjs.org/picomatch/-/picomatch-2.3.1.tgz",
@@ -2865,6 +3011,26 @@
         "fsevents": "~2.3.2"
       }
     },
+    "rollup-plugin-jscc": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/rollup-plugin-jscc/-/rollup-plugin-jscc-2.0.0.tgz",
+      "integrity": "sha512-5jG9q79K2u5uRBTKA+GA4gqt1zA7qHQRpcabZMoVs913gr75s428O7K3r58n2vADDzwIhiOKMo7rCMhOyks6dw==",
+      "dev": true,
+      "requires": {
+        "@jsbits/get-package-version": "^1.0.3",
+        "jscc": "^1.1.1",
+        "rollup-pluginutils": "^2.8.2"
+      }
+    },
+    "rollup-pluginutils": {
+      "version": "2.8.2",
+      "resolved": "https://registry.npmjs.org/rollup-pluginutils/-/rollup-pluginutils-2.8.2.tgz",
+      "integrity": "sha512-EEp9NhnUkwY8aif6bxgovPHMoMoNr2FulJziTndpt5H9RdwC47GSGuII9XxpSdzVGM0GWrNPHV6ie1LTNJPaLQ==",
+      "dev": true,
+      "requires": {
+        "estree-walker": "^0.6.1"
+      }
+    },
     "safe-buffer": {
       "version": "5.2.1",
       "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz",
@@ -2895,6 +3061,18 @@
       "integrity": "sha512-7++dFhtcx3353uBaq8DDR4NuxBetBzC7ZQOhmTQInHEd6bSrXdiEyzCvG07Z44UYdLShWUyXt5M/yhz8ekcb1A==",
       "dev": true
     },
+    "skip-regex": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/skip-regex/-/skip-regex-1.0.2.tgz",
+      "integrity": "sha512-pEjMUbwJ5Pl/6Vn6FsamXHXItJXSRftcibixDmNCWbWhic0hzHrwkMZo0IZ7fMRH9KxcWDFSkzhccB4285PutA==",
+      "dev": true
+    },
+    "sourcemap-codec": {
+      "version": "1.4.8",
+      "resolved": "https://registry.npmjs.org/sourcemap-codec/-/sourcemap-codec-1.4.8.tgz",
+      "integrity": "sha512-9NykojV5Uih4lgo5So5dtw+f0JgJX30KCNI8gwhz2J9A15wD0Ml6tjHKwf6fTSa6fAdVBdZeNOs9eJ71qCk8vA==",
+      "dev": true
+    },
     "string-width": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/string-width/-/string-width-2.1.1.tgz",
diff --git a/package.json b/package.json
index 34e1479..b8f2158 100644
--- a/package.json
+++ b/package.json
@@ -9,9 +9,11 @@
     "import": "./main.js",
     "require": "./build/main.cjs"
   },
+  "browser": "./build/main.ses.cjs",
   "scripts": {
     "test": "mocha",
-    "build": "rollup -c rollup.cjs.config.js"
+    "build": "rollup -c rollup.cjs.config.js",
+    "buildses": "SES=true rollup -c rollup.ses.config.js"
   },
   "repository": {
     "type": "git",
@@ -42,6 +44,7 @@
     "chai": "^4.2.0",
     "eslint": "^8.0.1",
     "mocha": "^8.2.1",
-    "rollup": "^2.38.5"
+    "rollup": "^2.38.5",
+    "rollup-plugin-jscc": "^2.0.0"
   }
 }
diff --git a/rollup.ses.config.js b/rollup.ses.config.js
new file mode 100644
index 0000000..40ff2fa
--- /dev/null
+++ b/rollup.ses.config.js
@@ -0,0 +1,18 @@
+import config from "./rollup.cjs.config.js";
+import jscc from 'rollup-plugin-jscc'
+
+export default {
+    input: "main.js",
+    output: {
+        file: "build/main.ses.cjs",
+        format: "cjs",
+    },
+    external: [
+        ...config.external,
+    ],
+    plugins: [
+      jscc({
+          values: { _SES: process.env.SES },
+      })
+    ],
+};
diff --git a/src/threadman.js b/src/threadman.js
index 61310a9..460db85 100644
--- a/src/threadman.js
+++ b/src/threadman.js
@@ -24,7 +24,11 @@ const MEM_SIZE = 25;  // Memory size in 64K Pakes (1600Kb)
 
 import thread from "./threadman_thread.js";
 import os from "os";
+
+/*#if _SES
+//#else */
 import Worker from "web-worker";
+//#endif
 
 class Deferred {
     constructor() {
@@ -40,7 +44,7 @@ function sleep(ms) {
 }
 
 function stringToBase64(str) {
-    if (process.browser) {
+    if (process.browser && typeof globalThis.btoa === "function") {
         return globalThis.btoa(str);
     } else {
         return Buffer.from(str).toString("base64");
@@ -81,7 +85,10 @@ export default async function buildThreadManager(wasm, singleThread) {
     //    tm.pTmp1 = tm.alloc(curve.G2.F.n8*3);
 
 
+/*#if _SES
+//#else */
     if (singleThread) {
+//#endif
         tm.code = wasm.code;
         tm.taskManager = thread();
         await tm.taskManager([{
@@ -90,6 +97,8 @@ export default async function buildThreadManager(wasm, singleThread) {
             code: tm.code.slice()
         }]);
         tm.concurrency  = 1;
+/*#if _SES
+//#else */
     } else {
         tm.workers = [];
         tm.pendingDeferreds = [];
@@ -133,6 +142,8 @@ export default async function buildThreadManager(wasm, singleThread) {
         await Promise.all(initPromises);
 
     }
+//#endif
+
     return tm;
 
     function getOnMsg(i) {