diff --git a/src/network/__tests__/useExchangeCodeForToken.test.tsx b/src/network/__tests__/useExchangeCodeForToken.test.tsx
index af21ae0..9d4c8fb 100644
--- a/src/network/__tests__/useExchangeCodeForToken.test.tsx
+++ b/src/network/__tests__/useExchangeCodeForToken.test.tsx
@@ -5,7 +5,7 @@ import { AuthProvider } from 'src/utils/AuthContext'
 import { asMock, currentAuthCredentials, userIsNotSignedIn, userIsSignedIn } from 'src/testHelpers'
 import { faker } from '@faker-js/faker'
 import { signInWithCode } from '../auth'
-import { currentUrlSearchParams } from 'src/utils/currentUrlSearchParams'
+import { currentUrlSearchParamsFor } from 'src/utils/currentUrlSearchParamsFor'
 import { navigate } from 'gatsby'
 
 jest.mock('src/network/auth', () => {
@@ -14,9 +14,9 @@ jest.mock('src/network/auth', () => {
   }
 })
 
-jest.mock('src/utils/currentUrlSearchParams', () => {
+jest.mock('src/utils/currentUrlSearchParamsFor', () => {
   return {
-    currentUrlSearchParams: jest.fn(),
+    currentUrlSearchParamsFor: jest.fn(),
   }
 })
 
@@ -56,9 +56,9 @@ describe('useExchangeCodeForToken', () => {
           ExpiresIn: faker.number.int({ min: 1000, max: 4000 }),
         },
       })
-      asMock(currentUrlSearchParams).mockReturnValue(new URLSearchParams(`code=${code}`))
+      asMock(currentUrlSearchParamsFor).mockReturnValue(code)
       asMock(navigate).mockImplementation(async () => {
-        asMock(currentUrlSearchParams).mockReturnValue(new URLSearchParams())
+        asMock(currentUrlSearchParamsFor).mockReturnValue(null)
       })
     })
 
@@ -86,9 +86,7 @@ describe('useExchangeCodeForToken', () => {
         kind: 'NOT_AUTHORIZED',
         error: { name: 'Not authorized', message: 'not authorized' },
       })
-      asMock(currentUrlSearchParams).mockReturnValue(
-        new URLSearchParams(`code=${faker.lorem.word()}`),
-      )
+      asMock(currentUrlSearchParamsFor).mockReturnValue(faker.lorem.word())
     })
 
     it('displays the error', async () => {
@@ -106,9 +104,7 @@ describe('useExchangeCodeForToken', () => {
     beforeEach(() => {
       asMock(navigate).mockClear()
       userIsSignedIn()
-      asMock(currentUrlSearchParams).mockReturnValue(
-        new URLSearchParams(`code=${faker.lorem.word()}`),
-      )
+      asMock(currentUrlSearchParamsFor).mockReturnValue(faker.lorem.word())
     })
 
     it('does not try to sign in', async () => {
diff --git a/src/network/useExchangeCodeForToken.ts b/src/network/useExchangeCodeForToken.ts
index da9f734..1b2b281 100644
--- a/src/network/useExchangeCodeForToken.ts
+++ b/src/network/useExchangeCodeForToken.ts
@@ -1,11 +1,11 @@
 import { useEffect, useState } from 'react'
 import { useAuth } from 'src/utils/AuthContext'
-import { currentUrlSearchParams } from 'src/utils/currentUrlSearchParams'
+import { currentUrlSearchParamsFor } from 'src/utils/currentUrlSearchParamsFor'
 import { signInWithCode } from './auth'
 import { navigate } from 'gatsby'
 
 export const useExchangeCodeForToken = () => {
-  const code: string | null = currentUrlSearchParams().get('code')
+  const code: string | null = currentUrlSearchParamsFor('code')
   const [loading, setLoading] = useState(false)
   const [auth, setAuth] = useAuth()
   const [errorMessage, setErrorMessage] = useState('')
diff --git a/src/utils/currentUrlSearchParams.ts b/src/utils/currentUrlSearchParams.ts
deleted file mode 100644
index 2c10c61..0000000
--- a/src/utils/currentUrlSearchParams.ts
+++ /dev/null
@@ -1 +0,0 @@
-export const currentUrlSearchParams = () => new URLSearchParams(window.location.search)
diff --git a/src/utils/currentUrlSearchParamsFor.ts b/src/utils/currentUrlSearchParamsFor.ts
new file mode 100644
index 0000000..d32aa9e
--- /dev/null
+++ b/src/utils/currentUrlSearchParamsFor.ts
@@ -0,0 +1,3 @@
+export const currentUrlSearchParamsFor = (key: string) => {
+  return typeof window !== 'undefined' ? new URLSearchParams(window.location.search).get(key) : null
+}
\ No newline at end of file