diff --git a/src/BaseCoder.web.ts b/src/BaseCoder.web.ts
new file mode 100644
index 0000000..6af7f22
--- /dev/null
+++ b/src/BaseCoder.web.ts
@@ -0,0 +1,33 @@
+import { Algorithm, Config } from './types/global';
+
+const isBrowser = typeof window !== `undefined`;
+
+export const encode = (
+  stringToEncode: string,
+  config: Config = { algorithm: Algorithm.base64Rfc4648 },
+) => {
+  if (!isBrowser) {
+    throw new Error(`Can only use BaseCoder in the browser.`);
+  }
+
+  if (config.algorithm !== Algorithm.base64Rfc4648) {
+    throw new Error(`Other algorithms than base64Rfc4648 are not supported yet.`);
+  }
+
+  return btoa(stringToEncode);
+};
+
+export const decode = (
+  bytesToEncode: string,
+  config: Config = { algorithm: Algorithm.base64Rfc4648 },
+) => {
+  if (!isBrowser) {
+    throw new Error(`Can only use BaseCoder in the browser.`);
+  }
+
+  if (config.algorithm !== Algorithm.base64Rfc4648) {
+    throw new Error(`Other algorithms than base64Rfc4648 are not supported yet.`);
+  }
+
+  return atob(bytesToEncode);
+};