diff --git a/packages/faucet/src/api/requestparser.spec.ts b/packages/faucet/src/api/requestparser.spec.ts
index 73512029..aeb53e38 100644
--- a/packages/faucet/src/api/requestparser.spec.ts
+++ b/packages/faucet/src/api/requestparser.spec.ts
@@ -7,6 +7,18 @@ describe("RequestParser", () => {
   });
 
   it("throws for invalid credit requests", () => {
+    // body not a dictionary
+    {
+      expect(() => RequestParser.parseCreditBody("foo")).toThrowError(/Request body must be a dictionary./i);
+      expect(() => RequestParser.parseCreditBody(null)).toThrowError(/Request body must be a dictionary./i);
+      expect(() => RequestParser.parseCreditBody(42)).toThrowError(/Request body must be a dictionary./i);
+      expect(() => RequestParser.parseCreditBody([])).toThrowError(/Request body must be a dictionary./i);
+      expect(() => RequestParser.parseCreditBody(true)).toThrowError(/Request body must be a dictionary./i);
+      expect(() => RequestParser.parseCreditBody(undefined)).toThrowError(
+        /Request body must be a dictionary./i,
+      );
+    }
+
     // address unset
     {
       const body = { ticker: "TKN" };
diff --git a/packages/faucet/src/api/requestparser.ts b/packages/faucet/src/api/requestparser.ts
index db938f73..77dda0f7 100644
--- a/packages/faucet/src/api/requestparser.ts
+++ b/packages/faucet/src/api/requestparser.ts
@@ -1,3 +1,5 @@
+import { isNonNullObject } from "@cosmjs/utils";
+
 import { HttpError } from "./httperror";
 
 export interface CreditRequestBodyData {
@@ -8,8 +10,12 @@ export interface CreditRequestBodyData {
 }
 
 export class RequestParser {
-  public static parseCreditBody(body: any): CreditRequestBodyData {
-    const { address, ticker } = body;
+  public static parseCreditBody(body: unknown): CreditRequestBodyData {
+    if (!isNonNullObject(body) || Array.isArray(body)) {
+      throw new HttpError(400, "Request body must be a dictionary.");
+    }
+
+    const { address, ticker } = body as any;
 
     if (typeof address !== "string") {
       throw new HttpError(400, "Property 'address' must be a string.");
diff --git a/packages/utils/src/typechecks.ts b/packages/utils/src/typechecks.ts
index 664fcc53..40faa05d 100644
--- a/packages/utils/src/typechecks.ts
+++ b/packages/utils/src/typechecks.ts
@@ -1,5 +1,10 @@
 /**
- * Checks if data is a non-null object (i.e. matches the TypeScript object type)
+ * Checks if data is a non-null object (i.e. matches the TypeScript object type).
+ *
+ * Note: this returns true for arrays, which are objects in JavaScript
+ * even though array and object are different types in JSON.
+ *
+ * @see https://www.typescriptlang.org/docs/handbook/basic-types.html#object
  */
 export function isNonNullObject(data: unknown): data is object {
   return typeof data === "object" && data !== null;
diff --git a/packages/utils/types/typechecks.d.ts b/packages/utils/types/typechecks.d.ts
index 3e911797..68c29628 100644
--- a/packages/utils/types/typechecks.d.ts
+++ b/packages/utils/types/typechecks.d.ts
@@ -1,5 +1,10 @@
 /**
- * Checks if data is a non-null object (i.e. matches the TypeScript object type)
+ * Checks if data is a non-null object (i.e. matches the TypeScript object type).
+ *
+ * Note: this returns true for arrays, which are objects in JavaScript
+ * even though array and object are different types in JSON.
+ *
+ * @see https://www.typescriptlang.org/docs/handbook/basic-types.html#object
  */
 export declare function isNonNullObject(data: unknown): data is object;
 /**