diff --git a/package-lock.json b/package-lock.json
index e9a0d3b..14efcd5 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@procedure-rpc/procedure.js",
-  "version": "0.9.0",
+  "version": "0.10.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "@procedure-rpc/procedure.js",
-      "version": "0.9.0",
+      "version": "0.10.0",
       "funding": [
         "https://github.com/procedure-rpc/procedure.js?sponsor=1",
         {
diff --git a/package.json b/package.json
index a7322ce..366a761 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@procedure-rpc/procedure.js",
-  "version": "0.9.0",
+  "version": "0.10.0",
   "title": "procedure.js",
   "description": "The simple RPC framework for Node.js.",
   "main": "./dist/index.js",
diff --git a/src/index.ts b/src/index.ts
index c5c3b5d..03863ff 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -126,13 +126,13 @@ export class Procedure<Input = undefined, Output = undefined>
 
     /**
      * Initializes a new {@link Procedure}.
-     * @param {Callback<Input, Output>} callback The underlying callback function powering the procedure itself. The callback may be asynchronous.
+     * @param {(input: Input) => Output} callback The underlying callback function powering the procedure itself. The callback may be asynchronous.
      * @param {Partial<ProcedureDefinitionOptions>} [options] Options for a {@link Procedure}. Defaults to `{}`.
      * @template Input Type of input parameter the procedure accepts. Defaults to `undefined`.
      * @template Output Type of output value the procedure returns. Defaults to `undefined`.
      */
     constructor(
-        protected callback: Callback<Input, Output>,
+        protected callback: (input: Input) => Output,
         options: Partial<ProcedureDefinitionOptions> = {}
     ) {
         super();
@@ -470,16 +470,6 @@ export class Procedure<Input = undefined, Output = undefined>
 }
 export default Procedure;
 
-/**
- * Represents a simple callback function which can take a single input parameter.
- * @template Input The type of input parameter the callback accepts. Defaults to `undefined`.
- * @template Output The type of output value the callback returns. Defaults to `undefined`.
- * @see {@link Procedure}
- */
-export type Callback<Input = undefined, Output = undefined> = (
-    input: Input
-) => Output;
-
 /**
  * A response from a {@link call Procedure call}.
  * If the call returned successfully, the response will be of shape `{ output: Output }`, otherwise `{ error: ProcedureError }`.
diff --git a/test/index.spec.ts b/test/index.spec.ts
index ea27b32..1ca4620 100644
--- a/test/index.spec.ts
+++ b/test/index.spec.ts
@@ -1,5 +1,5 @@
 import { ExtensionCodec } from '@msgpack/msgpack';
-import Procedure, { call, ping, tryPing, isPing, Callback } from '../src';
+import Procedure, { call, ping, tryPing, isPing } from '../src';
 import {
     ProcedureErrorCodes,
     ProcedureInternalServerError,
@@ -329,7 +329,7 @@ describe('Procedure', () => {
 });
 
 describe('call(endpoint: string, input: Input | null, options: Partial<ProcedureCallOptions>): Promise<Output>', () => {
-    let fn: Callback<unknown, unknown>;
+    let fn: ReturnType<typeof jest.fn>;
     let procedure: Procedure<unknown, unknown>;
     let procedureEndpoint: string;
     let input: unknown;
@@ -339,13 +339,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
         describe('when procedure callback: Callback<number, number> (simple accumulator function)', () => {
             beforeEach(() => {
                 let i = 0;
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return (i += n);
-                }));
+                });
                 procedureEndpoint = 'inproc://Procedure/Add';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -528,13 +528,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, null> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return null;
-                }));
+                });
                 procedureEndpoint = 'inproc://Procedure/ReturnsNull';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -717,13 +717,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, void> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return;
-                }));
+                });
                 procedureEndpoint = 'inproc://Procedure/ReturnsVoid';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -916,13 +916,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
         describe('when procedure callback: Callback<number, number> (simple accumulator function)', () => {
             beforeEach(() => {
                 let i = 0;
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return (i += n);
-                }));
+                });
                 procedureEndpoint = 'ipc://procedure/add';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -1105,13 +1105,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, null> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return null;
-                }));
+                });
                 procedureEndpoint = 'ipc://procedure/returnsnull';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -1294,13 +1294,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, void> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return;
-                }));
+                });
                 procedureEndpoint = 'ipc://procedure/returnsvoid';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -1486,13 +1486,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
         describe('when procedure callback: Callback<number, number> (simple accumulator function)', () => {
             beforeEach(() => {
                 let i = 0;
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return (i += n);
-                }));
+                });
                 procedureEndpoint = 'tcp://127.0.0.1:33333';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -1675,13 +1675,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, null> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return null;
-                }));
+                });
                 procedureEndpoint = 'tcp://127.0.0.1:33334';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -1864,13 +1864,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, void> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return;
-                }));
+                });
                 procedureEndpoint = 'tcp://127.0.0.1:33335';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -2056,13 +2056,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
         describe('when procedure callback: Callback<number, number> (simple accumulator function)', () => {
             beforeEach(() => {
                 let i = 0;
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return (i += n);
-                }));
+                });
                 procedureEndpoint = 'ws://127.0.0.1:33333';
                 procedure = new Procedure(fn, { workers: 3 });
                 procedure.bind(procedureEndpoint);
@@ -2245,13 +2245,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, null> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return null;
-                }));
+                });
 
                 procedureEndpoint = 'ws://127.0.0.1:33334';
                 procedure = new Procedure(fn, { workers: 3 });
@@ -2435,13 +2435,13 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 
         describe('when procedure callback: Callback<number, void> (testing nullish returns)', () => {
             beforeEach(() => {
-                fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+                fn = jest.fn((n: number) => {
                     if (typeof n !== 'number') {
                         throw new TypeError('Expected a number');
                     }
 
                     return;
-                }));
+                });
 
                 procedureEndpoint = 'ws://127.0.0.1:33335';
                 procedure = new Procedure(fn, { workers: 3 });
@@ -2626,7 +2626,7 @@ describe('call(endpoint: string, input: Input | null, options: Partial<Procedure
 });
 
 describe('ping(endpoint: string, timeout: number | undefined = 100, signal?: AbortSignal): Promise<boolean>', () => {
-    let fn: Callback<unknown, unknown>;
+    let fn: ReturnType<typeof jest.fn>;
     let procedure: Procedure<unknown, unknown>;
     let procedureEndpoint: string;
     let pingEndpoint: string | undefined;
@@ -2634,13 +2634,13 @@ describe('ping(endpoint: string, timeout: number | undefined = 100, signal?: Abo
     describe('when procedure callback: Callback<number, number> (simple accumulator function)', () => {
         beforeEach(() => {
             let i = 0;
-            fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+            fn = jest.fn((n: number) => {
                 if (typeof n !== 'number') {
                     throw new TypeError('Expected a number');
                 }
 
                 return (i += n);
-            }));
+            });
 
             procedureEndpoint = 'inproc://Procedure/Add';
             procedure = new Procedure(fn, { workers: 3 });
@@ -2690,8 +2690,7 @@ describe('ping(endpoint: string, timeout: number | undefined = 100, signal?: Abo
 });
 
 describe('tryPing(endpoint: string, timeout: number | undefined = 100, signal?: AbortSignal): Promise<boolean>', () => {
-    let fn: Callback<unknown, unknown>;
-
+    let fn: ReturnType<typeof jest.fn>;
     let procedure: Procedure<unknown, unknown>;
     let procedureEndpoint: string;
     let pingEndpoint: string | undefined;
@@ -2699,13 +2698,13 @@ describe('tryPing(endpoint: string, timeout: number | undefined = 100, signal?:
     describe('when procedure callback: Callback<number, number> (simple accumulator function)', () => {
         beforeEach(() => {
             let i = 0;
-            fn = jest.fn(<Callback<unknown, unknown>>((n: number) => {
+            fn = jest.fn((n: number) => {
                 if (typeof n !== 'number') {
                     throw new TypeError('Expected a number');
                 }
 
                 return (i += n);
-            }));
+            });
 
             procedureEndpoint = 'inproc://Procedure/Add';
             procedure = new Procedure(fn, { workers: 3 });