diff --git a/packages/auth/src/signature/middleware.ts b/packages/auth/src/signature/middleware.ts
index b29f91ad9e..cfc797e148 100644
--- a/packages/auth/src/signature/middleware.ts
+++ b/packages/auth/src/signature/middleware.ts
@@ -19,7 +19,7 @@ function contextToRequestLike(ctx: AppContext): RequestLike {
   return {
     url,
     method: ctx.method,
-    headers: JSON.parse(JSON.stringify(ctx.headers)),
+    headers: ctx.headers ? JSON.parse(JSON.stringify(ctx.headers)) : undefined,
     body: ctx.request.body ? JSON.stringify(ctx.request.body) : undefined
   }
 }
diff --git a/packages/auth/src/tests/context.ts b/packages/auth/src/tests/context.ts
index 78eb9ad784..e9ab37a4c0 100644
--- a/packages/auth/src/tests/context.ts
+++ b/packages/auth/src/tests/context.ts
@@ -52,7 +52,7 @@ export async function createContextWithSigHeaders<T extends AppContext>(
   const request = {
     url,
     method,
-    headers: JSON.parse(JSON.stringify(headers)),
+    headers: headers ? JSON.parse(JSON.stringify(headers)) : undefined,
     body: JSON.stringify(requestBody)
   }
   const sigHeaders = await createHeaders({
diff --git a/packages/backend/src/open_payments/auth/middleware.ts b/packages/backend/src/open_payments/auth/middleware.ts
index 45a3665261..74266e13c0 100644
--- a/packages/backend/src/open_payments/auth/middleware.ts
+++ b/packages/backend/src/open_payments/auth/middleware.ts
@@ -42,7 +42,7 @@ function contextToRequestLike(ctx: HttpSigContext): RequestLike {
   return {
     url,
     method: ctx.method,
-    headers: JSON.parse(JSON.stringify(ctx.headers)),
+    headers: ctx.headers ? JSON.parse(JSON.stringify(ctx.headers)) : undefined,
     body: ctx.request.body ? JSON.stringify(ctx.request.body) : undefined
   }
 }