diff --git a/apps/webapp/app/routes/account._index/route.tsx b/apps/webapp/app/routes/account._index/route.tsx
index 99ef9b87bb..3becdb99f1 100644
--- a/apps/webapp/app/routes/account._index/route.tsx
+++ b/apps/webapp/app/routes/account._index/route.tsx
@@ -22,6 +22,7 @@ import { useUser } from "~/hooks/useUser";
 import { redirectWithSuccessMessage } from "~/models/message.server";
 import { updateUser } from "~/models/user.server";
 import { requireUserId } from "~/services/session.server";
+import { emailSchema, MAX_EMAIL_LENGTH } from "~/utils/emailValidation";
 import { accountPath } from "~/utils/pathBuilder";
 
 export const meta: MetaFunction = () => {
@@ -42,30 +43,31 @@ function createSchema(
       .string({ required_error: "You must enter a name" })
       .min(2, "Your name must be at least 2 characters long")
       .max(50),
-    email: z
-      .string()
-      .email()
-      .superRefine((email, ctx) => {
-        if (constraints.isEmailUnique === undefined) {
-          //client-side validation skips this
+    email: emailSchema.superRefine((email, ctx) => {
+      if (email.length > MAX_EMAIL_LENGTH) {
+        return;
+      }
+
+      if (constraints.isEmailUnique === undefined) {
+        //client-side validation skips this
+        ctx.addIssue({
+          code: z.ZodIssueCode.custom,
+          message: conformZodMessage.VALIDATION_UNDEFINED,
+        });
+      } else {
+        // Tell zod this is an async validation by returning the promise
+        return constraints.isEmailUnique(email).then((isUnique) => {
+          if (isUnique) {
+            return;
+          }
+
           ctx.addIssue({
             code: z.ZodIssueCode.custom,
-            message: conformZodMessage.VALIDATION_UNDEFINED,
+            message: "Email is already being used by a different account",
           });
-        } else {
-          // Tell zod this is an async validation by returning the promise
-          return constraints.isEmailUnique(email).then((isUnique) => {
-            if (isUnique) {
-              return;
-            }
-
-            ctx.addIssue({
-              code: z.ZodIssueCode.custom,
-              message: "Email is already being used by a different account",
-            });
-          });
-        }
-      }),
+        });
+      }
+    }),
     marketingEmails: z.preprocess((value) => value === "on", z.boolean()),
   });
 }
@@ -177,6 +179,7 @@ export default function Page() {
                 <div className="flex w-56 flex-none flex-col gap-1">
                   <Input
                     {...getInputProps(email, { type: "text" })}
+                    maxLength={MAX_EMAIL_LENGTH}
                     placeholder="Your email"
                     defaultValue={user?.email ?? ""}
                   />
diff --git a/apps/webapp/app/routes/confirm-basic-details.tsx b/apps/webapp/app/routes/confirm-basic-details.tsx
index 9187823a73..ca14b53f0c 100644
--- a/apps/webapp/app/routes/confirm-basic-details.tsx
+++ b/apps/webapp/app/routes/confirm-basic-details.tsx
@@ -27,6 +27,7 @@ import { useUser } from "~/hooks/useUser";
 import { redirectWithSuccessMessage } from "~/models/message.server";
 import { updateUser } from "~/models/user.server";
 import { requireUserId } from "~/services/session.server";
+import { emailSchema, MAX_EMAIL_LENGTH } from "~/utils/emailValidation";
 import { rootPath } from "~/utils/pathBuilder";
 import { getVercelInstallParams } from "~/v3/vercel";
 
@@ -72,29 +73,30 @@ function createSchema(
   return z
     .object({
       name: z.string().min(3, "Your name must be at least 3 characters").max(50),
-      email: z
-        .string()
-        .email()
-        .superRefine((email, ctx) => {
-          if (constraints.isEmailUnique === undefined) {
+      email: emailSchema.superRefine((email, ctx) => {
+        if (email.length > MAX_EMAIL_LENGTH) {
+          return;
+        }
+
+        if (constraints.isEmailUnique === undefined) {
+          ctx.addIssue({
+            code: z.ZodIssueCode.custom,
+            message: conformZodMessage.VALIDATION_UNDEFINED,
+          });
+        } else {
+          return constraints.isEmailUnique(email).then((isUnique) => {
+            if (isUnique) {
+              return;
+            }
+
             ctx.addIssue({
               code: z.ZodIssueCode.custom,
-              message: conformZodMessage.VALIDATION_UNDEFINED,
-            });
-          } else {
-            return constraints.isEmailUnique(email).then((isUnique) => {
-              if (isUnique) {
-                return;
-              }
-
-              ctx.addIssue({
-                code: z.ZodIssueCode.custom,
-                message: "Email is already being used by a different account",
-              });
+              message: "Email is already being used by a different account",
             });
-          }
-        }),
-      confirmEmail: z.string(),
+          });
+        }
+      }),
+      confirmEmail: emailSchema,
       referralSource: z.string().optional(),
       referralSourceOther: z.string().optional(),
       role: z.string().optional(),
@@ -290,6 +292,7 @@ export default function Page() {
                 </Label>
                 <Input
                   {...getInputProps(email, { type: "email" })}
+                  maxLength={MAX_EMAIL_LENGTH}
                   defaultValue={enteredEmail}
                   onChange={(e) => {
                     setEnteredEmail(e.target.value);
@@ -306,6 +309,7 @@ export default function Page() {
                   <Label htmlFor={confirmEmail.id}>Confirm email</Label>
                   <Input
                     {...getInputProps(confirmEmail, { type: "email" })}
+                    maxLength={MAX_EMAIL_LENGTH}
                     placeholder="Your email, again"
                     icon={EnvelopeIcon}
                     spellCheck={false}
diff --git a/apps/webapp/app/utils/emailValidation.ts b/apps/webapp/app/utils/emailValidation.ts
new file mode 100644
index 0000000000..e754551a46
--- /dev/null
+++ b/apps/webapp/app/utils/emailValidation.ts
@@ -0,0 +1,8 @@
+import { z } from "zod";
+
+export const MAX_EMAIL_LENGTH = 254;
+
+export const emailSchema = z
+  .string()
+  .max(MAX_EMAIL_LENGTH, `Email must be ${MAX_EMAIL_LENGTH} characters or fewer`)
+  .pipe(z.string().email());
diff --git a/apps/webapp/test/emailValidation.test.ts b/apps/webapp/test/emailValidation.test.ts
new file mode 100644
index 0000000000..968520feac
--- /dev/null
+++ b/apps/webapp/test/emailValidation.test.ts
@@ -0,0 +1,28 @@
+import { describe, expect, it } from "vitest";
+import { emailSchema, MAX_EMAIL_LENGTH } from "~/utils/emailValidation";
+
+function emailWithLength(length: number) {
+  const domain = "@example.com";
+  return `${"a".repeat(length - domain.length)}${domain}`;
+}
+
+describe("emailSchema", () => {
+  it("accepts an email at the maximum length", () => {
+    expect(emailSchema.safeParse(emailWithLength(MAX_EMAIL_LENGTH)).success).toBe(true);
+  });
+
+  it("rejects an email over the maximum length", () => {
+    const result = emailSchema.safeParse(emailWithLength(MAX_EMAIL_LENGTH + 1));
+
+    expect(result.success).toBe(false);
+    if (result.success) {
+      throw new Error("Expected an overlong email to be rejected");
+    }
+
+    expect(result.error.issues).toContainEqual(
+      expect.objectContaining({
+        message: `Email must be ${MAX_EMAIL_LENGTH} characters or fewer`,
+      })
+    );
+  });
+});