diff --git a/packages/auth-fetch/src/auth-fetch.ts b/packages/auth-fetch/src/auth-fetch.ts
index a6ff2fea73..8b69be03d9 100644
--- a/packages/auth-fetch/src/auth-fetch.ts
+++ b/packages/auth-fetch/src/auth-fetch.ts
@@ -70,7 +70,7 @@ async function getAuth(options: AuthFetchOptions, url: string | URL, method: str
 
 export function createAuthFetch<B, M>(
     h: fetcher<B, M>,
-    parser: (body: M, responseType: HttpFetchResponseType) => Promise<any>
+    parser: (body: M, responseType: HttpFetchResponseType | undefined) => Promise<any>
 ) {
     const authHttpFetch = async <T extends HttpFetchOptions<B>>(options: T & AuthFetchOptions): ReturnType<typeof h<T>> => {
         const method = getFetchMethod(options);
@@ -99,7 +99,7 @@ export function createAuthFetch<B, M>(
             };
         }
 
-        let authenticateHeaders: string | string[] = initialResponse.headers.get('www-authenticate');
+        let authenticateHeaders: string | string[] | null = initialResponse.headers.get('www-authenticate');
         if (!authenticateHeaders)
             throw new Error('Did not find WWW-Authenticate header.');
 
diff --git a/packages/auth-fetch/tsconfig.json b/packages/auth-fetch/tsconfig.json
index 8f3b71a840..b1e73c4826 100644
--- a/packages/auth-fetch/tsconfig.json
+++ b/packages/auth-fetch/tsconfig.json
@@ -9,6 +9,7 @@
         "inlineSources": true,
         "declaration": true,
         "resolveJsonModule": true,
+        "strict": true
     },
     "include": [
         "src/**/*"
diff --git a/server/src/fetch/http-fetch.ts b/server/src/fetch/http-fetch.ts
index 00c19a5896..830626b6f5 100644
--- a/server/src/fetch/http-fetch.ts
+++ b/server/src/fetch/http-fetch.ts
@@ -41,7 +41,7 @@ const StreamParser: FetchParser<IncomingMessage> = {
     }
 }
 
-export function getHttpFetchParser(responseType: HttpFetchResponseType) {
+export function getHttpFetchParser(responseType: HttpFetchResponseType | undefined) {
     switch (responseType) {
         case 'json':
             return JSONParser;
@@ -53,7 +53,7 @@ export function getHttpFetchParser(responseType: HttpFetchResponseType) {
     return BufferParser;
 }
 
-export function httpFetchParseIncomingMessage(readable: IncomingMessage, responseType: HttpFetchResponseType) {
+export function httpFetchParseIncomingMessage(readable: IncomingMessage, responseType: HttpFetchResponseType | undefined) {
     return getHttpFetchParser(responseType).parse(readable);
 }
 
diff --git a/server/src/fetch/index.ts b/server/src/fetch/index.ts
index f0e35e40ba..745c518d1b 100644
--- a/server/src/fetch/index.ts
+++ b/server/src/fetch/index.ts
@@ -62,7 +62,7 @@ export type fetcher<B, M> = <T extends HttpFetchOptions<B>>(options: T) => Promi
 >>;
 
 
-export function getHttpFetchAccept(responseType: HttpFetchResponseType) {
+export function getHttpFetchAccept(responseType: HttpFetchResponseType | undefined) {
     switch (responseType) {
         case 'json':
             return 'application/json';
@@ -89,7 +89,7 @@ export function setHeader(headers: [string, string][], key: string, value: strin
     headers.push([key, value]);
 }
 
-export function setDefaultHttpFetchAccept(headers: [string, string][], responseType: HttpFetchResponseType) {
+export function setDefaultHttpFetchAccept(headers: [string, string][], responseType: HttpFetchResponseType | undefined) {
     if (hasHeader(headers, 'Accept'))
         return;
     const accept = getHttpFetchAccept(responseType);
@@ -97,7 +97,7 @@ export function setDefaultHttpFetchAccept(headers: [string, string][], responseT
         setHeader(headers, 'Accept', accept);
 }
 
-export function createHeadersArray(headers: HeadersInit): [string, string][] {
+export function createHeadersArray(headers: HeadersInit | undefined): [string, string][] {
     const headersArray: [string, string][] = [];
     if (!headers)
         return headersArray;
@@ -144,7 +144,7 @@ export function createStringOrBufferBody(headers: [string, string][], body: any)
     return body;
 }
 
-export async function domFetchParseIncomingMessage(response: Response, responseType: HttpFetchResponseType) {
+export async function domFetchParseIncomingMessage(response: Response, responseType: HttpFetchResponseType | undefined) {
     switch (responseType) {
         case 'json':
             return response.json();