diff --git a/gulpfile.cjs b/gulpfile.cjs
index 8a6f459a..09b4deb0 100644
--- a/gulpfile.cjs
+++ b/gulpfile.cjs
@@ -1,21 +1,17 @@
 const {spawn} = require('child_process');
 const del = require('del');
 const {promises} = require('fs');
-const {dest, series, src, task, watch} = require('gulp');
-const replace = require('gulp-replace');
+const {series, task, watch} = require('gulp');
 const {EOL} = require('os');
 const {delimiter, normalize, resolve} = require('path');
 
 // Initialize the build system.
-const _path = 'PATH' in process.env ? process.env.PATH : '';
+const _path = process.env.PATH ?? '';
 const _vendor = resolve('node_modules/.bin');
 if (!_path.includes(_vendor)) process.env.PATH = `${_vendor}${delimiter}${_path}`;
 
 /** Builds the project. */
-const esmRegex = /(export|import)\s+(.+)\s+from\s+'((?!.*\.js)\.[^']+)'/g;
-task('build:fix', () => src('lib/**/*.js').pipe(replace(esmRegex, "$1 $2 from '$3.js'")).pipe(dest('lib')));
-task('build:js', () => _exec('tsc', ['--project', 'src/tsconfig.json']));
-task('build', series('build:js', 'build:fix'));
+task('build', () => _exec('tsc', ['--project', 'src/tsconfig.json']));
 
 /** Deletes all generated files and reset any saved state. */
 task('clean', () => del(['build', 'doc/api', 'lib', 'var/**/*', 'web']));
diff --git a/lib/author.d.ts b/lib/author.d.ts
index a5d4f811..fa8583c2 100644
--- a/lib/author.d.ts
+++ b/lib/author.d.ts
@@ -1,4 +1,4 @@
-import { JsonObject } from './json';
+import { JsonObject } from './json.js';
 /** Represents the author of a comment. */
 export declare class Author {
     ipAddress: string;
diff --git a/lib/blog.d.ts b/lib/blog.d.ts
index bc94d386..e8b0b9ed 100644
--- a/lib/blog.d.ts
+++ b/lib/blog.d.ts
@@ -1,4 +1,4 @@
-import { JsonObject } from './json';
+import { JsonObject } from './json.js';
 /** Represents the front page or home URL transmitted when making requests. */
 export declare class Blog {
     url?: URL | undefined;
diff --git a/lib/client.d.ts b/lib/client.d.ts
index a63c309a..96c687c5 100644
--- a/lib/client.d.ts
+++ b/lib/client.d.ts
@@ -1,7 +1,7 @@
 /// <reference types="node" />
 import { EventEmitter } from 'events';
-import { Blog } from './blog';
-import { Comment } from './comment';
+import { Blog } from './blog.js';
+import { Comment } from './comment.js';
 /** Specifies the result of a comment check. */
 export declare enum CheckResult {
     /** The comment is not a spam (i.e. a ham). */
diff --git a/lib/comment.d.ts b/lib/comment.d.ts
index e1b380d3..51e7dbb3 100644
--- a/lib/comment.d.ts
+++ b/lib/comment.d.ts
@@ -1,5 +1,5 @@
-import { Author } from './author';
-import { JsonObject } from './json';
+import { Author } from './author.js';
+import { JsonObject } from './json.js';
 /** Represents a comment submitted by an author. */
 export declare class Comment {
     author?: Author | undefined;
diff --git a/lib/index.d.ts b/lib/index.d.ts
index 1132f1b4..234d9181 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -1,5 +1,5 @@
-export * from './author';
-export * from './blog';
-export * from './client';
-export * from './comment';
-export * from './json';
+export * from './author.js';
+export * from './blog.js';
+export * from './client.js';
+export * from './comment.js';
+export * from './json.js';
diff --git a/share/api.http b/share/api.http
index cdf425d0..711154f7 100644
--- a/share/api.http
+++ b/share/api.http
@@ -2,7 +2,7 @@
 POST {{baseUrl}}/comment-check
 Content-Type: application/x-www-form-urlencoded
 
-blog=https%3A%2F%2Fdev.belin.io%2Fakismet.js&comment_author=Akismet&comment_author_url=https%3A%2F%2Fdev.belin.io%2Fakismet.js&comment_content=I'm%20testing%20out%20the%20Service%20API.&comment_type=comment&is_test=true&referrer=https%3A%2F%2Fwww.npmjs.com%2Fpackage%2F%40cedx%2Fakismet&user_agent=Mozilla%2F5.0%20(Windows%20NT%2010.0%3B%20Win64%3B%20x64%3B%20rv%3A70.0)%20Gecko%2F20100101%20Firefox%2F70.0&user_ip=192.168.0.1&user_role=administrator
+blog=https%3A%2F%2Fdocs.belin.io%2Fakismet.js&comment_author=Akismet&comment_author_url=https%3A%2F%2Fdocs.belin.io%2Fakismet.js&comment_content=I'm%20testing%20out%20the%20Service%20API.&comment_type=comment&is_test=true&referrer=https%3A%2F%2Fwww.npmjs.com%2Fpackage%2F%40cedx%2Fakismet&user_agent=Mozilla%2F5.0%20(Windows%20NT%2010.0%3B%20Win64%3B%20x64%3B%20rv%3A70.0)%20Gecko%2F20100101%20Firefox%2F70.0&user_ip=192.168.0.1&user_role=administrator
 
 ###
 
@@ -10,6 +10,6 @@ blog=https%3A%2F%2Fdev.belin.io%2Fakismet.js&comment_author=Akismet&comment_auth
 POST {{baseUrl}}/comment-check
 Content-Type: application/x-www-form-urlencoded
 
-blog=https%3A%2F%2Fdev.belin.io%2Fakismet.js&comment_author=viagra-test-123&comment_content=Spam!&comment_type=trackback&comment_author_email=akismet-guaranteed-spam%40example.com&is_test=true&user_ip=127.0.0.1&user_agent=Spam%20Bot%2F6.6.6
+blog=https%3A%2F%2Fdocs.belin.io%2Fakismet.js&comment_author=viagra-test-123&comment_content=Spam!&comment_type=trackback&comment_author_email=akismet-guaranteed-spam%40example.com&is_test=true&user_ip=127.0.0.1&user_agent=Spam%20Bot%2F6.6.6
 
 ###
diff --git a/src/author.ts b/src/author.ts
index 1be3a42f..bedbf1d8 100644
--- a/src/author.ts
+++ b/src/author.ts
@@ -1,4 +1,4 @@
-import {JsonObject} from './json';
+import {JsonObject} from './json.js';
 
 /** Represents the author of a comment. */
 export class Author {
diff --git a/src/blog.ts b/src/blog.ts
index 98e54d43..a095440b 100644
--- a/src/blog.ts
+++ b/src/blog.ts
@@ -1,4 +1,4 @@
-import {JsonObject} from './json';
+import {JsonObject} from './json.js';
 
 /** Represents the front page or home URL transmitted when making requests. */
 export class Blog {
diff --git a/src/client.ts b/src/client.ts
index fe2024ba..c95a69db 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -1,9 +1,9 @@
 import {EventEmitter} from 'events';
 import fetch, {Response} from 'node-fetch';
-import {Blog} from './blog';
-import {Comment} from './comment';
-import {JsonObject} from './json';
-import {packageVersion} from './version.g';
+import {Blog} from './blog.js';
+import {Comment} from './comment.js';
+import {JsonObject} from './json.js';
+import {packageVersion} from './version.g.js';
 
 /** Specifies the result of a comment check. */
 export enum CheckResult {
diff --git a/src/comment.ts b/src/comment.ts
index a83607f5..1eee9988 100644
--- a/src/comment.ts
+++ b/src/comment.ts
@@ -1,5 +1,5 @@
-import {Author} from './author';
-import {JsonObject} from './json';
+import {Author} from './author.js';
+import {JsonObject} from './json.js';
 
 /** Represents a comment submitted by an author. */
 export class Comment {
diff --git a/src/index.ts b/src/index.ts
index 1132f1b4..234d9181 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,5 +1,5 @@
-export * from './author';
-export * from './blog';
-export * from './client';
-export * from './comment';
-export * from './json';
+export * from './author.js';
+export * from './blog.js';
+export * from './client.js';
+export * from './comment.js';
+export * from './json.js';
diff --git a/src/tsconfig.json b/src/tsconfig.json
index 9587e023..5d3dde28 100644
--- a/src/tsconfig.json
+++ b/src/tsconfig.json
@@ -8,7 +8,7 @@
     "moduleResolution": "node",
     "outDir": "../lib",
     "strict": true,
-    "target": "es2019",
+    "target": "es2020",
     "tsBuildInfoFile": "../var/tsbuild.json"
   }
 }