diff --git a/packages/config/DittoConfig.ts b/packages/config/DittoConfig.ts
index 2aee123f..b11ca681 100644
--- a/packages/config/DittoConfig.ts
+++ b/packages/config/DittoConfig.ts
@@ -1,11 +1,11 @@
 import os from 'node:os';
 import ISO6391, { type LanguageCode } from 'iso-639-1';
 import { getPublicKey, nip19 } from 'nostr-tools';
-import { z } from 'zod';
 import { decodeBase64 } from '@std/encoding/base64';
 import { encodeBase64Url } from '@std/encoding/base64url';
 
 import { getEcdsaPublicKey } from './utils/crypto.ts';
+import { optionalBooleanSchema, optionalNumberSchema } from './utils/schema.ts';
 
 /** Ditto application-wide configuration. */
 export class DittoConfig {
@@ -462,16 +462,6 @@ export class DittoConfig {
   }
 }
 
-const optionalBooleanSchema = z
-  .enum(['true', 'false'])
-  .optional()
-  .transform((value) => value !== undefined ? value === 'true' : undefined);
-
-const optionalNumberSchema = z
-  .string()
-  .optional()
-  .transform((value) => value !== undefined ? Number(value) : undefined);
-
 function mergePaths(base: string, path: string) {
   const url = new URL(
     path.startsWith('/') ? path : new URL(path).pathname,
diff --git a/packages/config/utils/schema.test.ts b/packages/config/utils/schema.test.ts
new file mode 100644
index 00000000..9a52efe0
--- /dev/null
+++ b/packages/config/utils/schema.test.ts
@@ -0,0 +1,17 @@
+import { assertEquals, assertThrows } from '@std/assert';
+
+import { optionalBooleanSchema, optionalNumberSchema } from './schema.ts';
+
+Deno.test('optionalBooleanSchema', () => {
+  assertEquals(optionalBooleanSchema.parse('true'), true);
+  assertEquals(optionalBooleanSchema.parse('false'), false);
+  assertEquals(optionalBooleanSchema.parse(undefined), undefined);
+
+  assertThrows(() => optionalBooleanSchema.parse('invalid'));
+});
+
+Deno.test('optionalNumberSchema', () => {
+  assertEquals(optionalNumberSchema.parse('123'), 123);
+  assertEquals(optionalNumberSchema.parse('invalid'), NaN); // maybe this should throw?
+  assertEquals(optionalNumberSchema.parse(undefined), undefined);
+});
diff --git a/packages/config/utils/schema.ts b/packages/config/utils/schema.ts
new file mode 100644
index 00000000..dcd1f85e
--- /dev/null
+++ b/packages/config/utils/schema.ts
@@ -0,0 +1,11 @@
+import { z } from 'zod';
+
+export const optionalBooleanSchema = z
+  .enum(['true', 'false'])
+  .optional()
+  .transform((value) => value !== undefined ? value === 'true' : undefined);
+
+export const optionalNumberSchema = z
+  .string()
+  .optional()
+  .transform((value) => value !== undefined ? Number(value) : undefined);