diff --git a/landing/siwe.react.js b/landing/siwe.react.js
--- a/landing/siwe.react.js
+++ b/landing/siwe.react.js
@@ -5,6 +5,7 @@
   getDefaultWallets,
   RainbowKitProvider,
 } from '@rainbow-me/rainbowkit';
+import invariant from 'invariant';
 import * as React from 'react';
 import { SiweMessage } from 'siwe';
 import '@rainbow-me/rainbowkit/dist/index.css';
@@ -18,6 +19,7 @@
 } from 'wagmi';
 import { publicProvider } from 'wagmi/providers/public';
 
+import { SIWENonceContext } from './siwe-nonce-context.js';
 import css from './siwe.css';
 
 // details can be found https://wagmi.sh/docs/providers/configuring-chains
@@ -37,7 +39,8 @@
   provider,
 });
 
-function createSiweMessage(address, statement) {
+function createSiweMessage(address: string, statement: string, nonce: string) {
+  invariant(nonce, 'nonce must be present in createSiweMessage');
   const domain = window.location.host;
   const origin = window.location.origin;
   const message = new SiweMessage({
@@ -47,14 +50,17 @@
     uri: origin,
     version: '1',
     chainId: '1',
+    nonce,
   });
   return message.prepareMessage();
 }
 
-async function signInWithEthereum(address, signer) {
+async function signInWithEthereum(address: string, signer, nonce: string) {
+  invariant(nonce, 'nonce must be present in signInWithEthereum');
   const message = createSiweMessage(
     address,
     'By continuing, I accept the Comm Terms of Service: https://comm.app/terms',
+    nonce,
   );
   const signature = await signer.signMessage(message);
   const messageToPost = JSON.stringify({ address, message, signature });
@@ -65,10 +71,20 @@
 function SIWE(): React.Node {
   const { address } = useAccount();
   const { data: signer } = useSigner();
-  const onClick = React.useCallback(() => signInWithEthereum(address, signer), [
-    address,
-    signer,
-  ]);
+  const { siweNonce } = React.useContext(SIWENonceContext);
+  const onClick = React.useCallback(() => {
+    invariant(siweNonce, 'nonce must be present during SIWE attempt');
+    signInWithEthereum(address, signer, siweNonce);
+  }, [address, signer, siweNonce]);
+
+  if (siweNonce === null || siweNonce === undefined) {
+    return (
+      <div className={css.wrapper}>
+        <h1 className={css.h1}>Unable to proceed: nonce not found.</h1>
+      </div>
+    );
+  }
+
   const SignInButton = !signer ? null : (
     <div className={css.button} onClick={onClick}>
       <img src="images/ethereum_icon.svg" style={ethIconStyle} />