diff --git a/src/App.tsx b/src/App.tsx
index 017957182..85f02c52b 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -4,57 +4,137 @@ import 'bulma/css/bulma.css';
 import '@fortawesome/fontawesome-free/css/all.css';
 import './App.scss';
 
-import { PostsList } from './components/PostsList';
-import { PostDetails } from './components/PostDetails';
 import { UserSelector } from './components/UserSelector';
+import React, { useEffect } from 'react';
+import { User } from './types/User';
+import { getPostsOfUser, getUsers } from './utils/api';
+import { Post } from './types/Post';
+import { PostsList } from './components/PostsList';
 import { Loader } from './components/Loader';
+import { PostDetails } from './components/PostDetails';
 
-export const App = () => (
-  <main className="section">
-    <div className="container">
-      <div className="tile is-ancestor">
-        <div className="tile is-parent">
-          <div className="tile is-child box is-success">
-            <div className="block">
-              <UserSelector />
-            </div>
+export const App = () => {
+  const [usersFromServer, setUsersFromServer] = React.useState<User[]>();
+  const [postsFromServer, setPostsFromServer] = React.useState<Post[]>();
 
-            <div className="block" data-cy="MainContent">
-              <p data-cy="NoSelectedUser">No user selected</p>
+  const [chosenUser, setChosenUser] = React.useState<User | null>(null);
+  const [postError, setPostError] = React.useState(false);
+  const [isPostsLoading, setIsPostsLoading] = React.useState(false);
+  const [activePost, setActivePost] = React.useState<Post | null>(null);
 
-              <Loader />
+  // Стан для помилок під час завантаження користувачів
+  const [userErrors, setUserErrors] = React.useState(false);
 
-              <div
-                className="notification is-danger"
-                data-cy="PostsLoadingError"
-              >
-                Something went wrong!
-              </div>
+  // Завантажуємо користувачів
+  useEffect(() => {
+    const fetchUsers = async () => {
+      try {
+        const currentUsers = await getUsers();
+
+        setUsersFromServer(currentUsers);
+      } catch (err) {
+        setUserErrors(true);
+      }
+    };
+
+    fetchUsers();
+  }, []);
 
-              <div className="notification is-warning" data-cy="NoPostsYet">
-                No posts yet
+  // Завантажуємо пости обраного користувача
+  useEffect(() => {
+    const fetchPosts = async () => {
+      setIsPostsLoading(true);
+      try {
+        const currentPosts = await getPostsOfUser(chosenUser?.id ?? 0);
+
+        setPostsFromServer(currentPosts);
+      } catch (err) {
+        setPostError(true);
+      } finally {
+        setIsPostsLoading(false);
+      }
+    };
+
+    if (chosenUser) {
+      setActivePost(null);
+      fetchPosts();
+    }
+  }, [chosenUser]);
+
+  return (
+    <main className="section">
+      <div className="container">
+        <div className="tile is-ancestor">
+          <div className="tile is-parent">
+            <div className="tile is-child box is-success">
+              <div className="block">
+                {/*
+                  Передаємо у UserSelector порожній масив
+                  замість null, щоб уникнути помилок .map()
+                */}
+                <UserSelector
+                  users={usersFromServer ?? []}
+                  chosenUser={chosenUser}
+                  chooseUser={setChosenUser}
+                />
               </div>
 
-              <PostsList />
+              <div className="block" data-cy="MainContent">
+                {/* Якщо помилка при завантаженні користувачів */}
+                {userErrors && (
+                  <div
+                    className="notification is-danger"
+                    data-cy="UsersLoadingError"
+                  >
+                    Failed to load users. Please try again later.
+                  </div>
+                )}
+
+                {/* Якщо нема обраного користувача */}
+                {!userErrors && !chosenUser ? (
+                  <p data-cy="NoSelectedUser">No user selected</p>
+                ) : isPostsLoading ? (
+                  <Loader />
+                ) : postError ? (
+                  <div
+                    className="notification is-danger"
+                    data-cy="PostsLoadingError"
+                  >
+                    Something went wrong!
+                  </div>
+                ) : postsFromServer?.length === 0 ? (
+                  <div className="notification is-warning" data-cy="NoPostsYet">
+                    No posts yet
+                  </div>
+                ) : (
+                  <PostsList
+                    posts={postsFromServer}
+                    activePost={activePost}
+                    choosePost={setActivePost}
+                  />
+                )}
+              </div>
             </div>
           </div>
-        </div>
 
-        <div
-          data-cy="Sidebar"
-          className={classNames(
-            'tile',
-            'is-parent',
-            'is-8-desktop',
-            'Sidebar',
-            'Sidebar--open',
-          )}
-        >
-          <div className="tile is-child box is-success ">
-            <PostDetails />
+          <div
+            data-cy="Sidebar"
+            className={classNames(
+              'tile',
+              'is-parent',
+              'is-8-desktop',
+              'Sidebar',
+              { 'Sidebar--open': activePost },
+            )}
+          >
+            {activePost && (
+              <div className="tile is-child box is-success">
+                <PostDetails post={activePost} />
+              </div>
+            )}
           </div>
         </div>
       </div>
-    </div>
-  </main>
-);
+    </main>
+  );
+};
diff --git a/src/components/NewCommentForm.tsx b/src/components/NewCommentForm.tsx
index 73a8a0b45..b9c8debd7 100644
--- a/src/components/NewCommentForm.tsx
+++ b/src/components/NewCommentForm.tsx
@@ -1,8 +1,89 @@
-import React from 'react';
+import React, { useState } from 'react';
+import { addComment } from '../utils/api';
+import { Comment } from '../types/Comment';
+
+type Props = {
+  postId: number;
+  onCommentAdded: (newComment: Comment) => void;
+};
+
+export const NewCommentForm: React.FC<Props> = ({ postId, onCommentAdded }) => {
+  const [name, setName] = useState<string>('');
+  const [email, setEmail] = useState<string>('');
+  const [body, setBody] = useState<string>('');
+  const [errors, setErrors] = useState<{
+    name?: string;
+    email?: string;
+    body?: string;
+  }>({});
+  const [isSubmitting, setIsSubmitting] = useState<boolean>(false);
+  const [formError, setFormError] = useState<string | null>(null);
+
+  const validate = () => {
+    const newErrors: typeof errors = {};
+
+    if (!name.trim()) {
+      newErrors.name = 'Name is required';
+    }
+
+    if (!email.trim() || !/^[\w.%+-]+@[\w.-]+\.[a-zA-Z]{2,}$/.test(email)) {
+      newErrors.email = 'Email is required';
+    }
+
+    if (!body.trim()) {
+      newErrors.body = 'Enter some text';
+    }
+
+    setErrors(newErrors);
+
+    return Object.keys(newErrors).length === 0;
+  };
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault();
+    setFormError(null);
+
+    if (!validate()) {
+      return;
+    }
+
+    setIsSubmitting(true);
+
+    try {
+      const newComment: Comment = await addComment({
+        postId,
+        name,
+        email,
+        body,
+      });
+
+      onCommentAdded(newComment);
+
+      setBody('');
+      setErrors({});
+    } catch (err) {
+      setFormError('Failed to add comment. Please try again later.');
+    } finally {
+      setIsSubmitting(false);
+    }
+  };
+
+  const handleClear = () => {
+    setName('');
+    setEmail('');
+    setBody('');
+    setErrors({});
+    setFormError(null);
+  };
 
-export const NewCommentForm: React.FC = () => {
   return (
-    <form data-cy="NewCommentForm">
+    <form onSubmit={handleSubmit} data-cy="NewCommentForm" className="box">
+      {formError && (
+        <div className="notification is-danger" data-cy="FormError">
+          {formError}
+        </div>
+      )}
+
       <div className="field" data-cy="NameField">
         <label className="label" htmlFor="comment-author-name">
           Author Name
@@ -11,29 +92,36 @@ export const NewCommentForm: React.FC = () => {
         <div className="control has-icons-left has-icons-right">
           <input
             type="text"
-            name="name"
             id="comment-author-name"
+            className={`input ${errors.name ? 'is-danger' : ''}`}
+            value={name}
+            onChange={e => {
+              setName(e.target.value);
+              setErrors(prev => ({ ...prev, name: undefined }));
+            }}
             placeholder="Name Surname"
-            className="input is-danger"
           />
 
           <span className="icon is-small is-left">
-            <i className="fas fa-user" />
+            <i className="fas fa-user"></i>
           </span>
 
-          <span
-            className="icon is-small is-right has-text-danger"
-            data-cy="ErrorIcon"
-          >
-            <i className="fas fa-exclamation-triangle" />
-          </span>
+          {errors.name && (
+            <span
+              className="icon is-small is-right has-text-danger"
+              data-cy="ErrorIcon"
+            >
+              <i className="fas fa-exclamation-triangle" />
+            </span>
+          )}
         </div>
 
-        <p className="help is-danger" data-cy="ErrorMessage">
-          Name is required
-        </p>
+        {errors.name && (
+          <p className="help is-danger" data-cy="ErrorMessage">
+            {errors.name}
+          </p>
+        )}
       </div>
-
       <div className="field" data-cy="EmailField">
         <label className="label" htmlFor="comment-author-email">
           Author Email
@@ -41,28 +129,36 @@ export const NewCommentForm: React.FC = () => {
 
         <div className="control has-icons-left has-icons-right">
           <input
-            type="text"
-            name="email"
+            type="email"
             id="comment-author-email"
+            className={`input ${errors.email ? 'is-danger' : ''}`}
+            value={email}
+            onChange={e => {
+              setEmail(e.target.value);
+              setErrors(prev => ({ ...prev, email: undefined }));
+            }}
             placeholder="email@test.com"
-            className="input is-danger"
           />
 
           <span className="icon is-small is-left">
-            <i className="fas fa-envelope" />
+            <i className="fas fa-envelope"></i>
           </span>
 
-          <span
-            className="icon is-small is-right has-text-danger"
-            data-cy="ErrorIcon"
-          >
-            <i className="fas fa-exclamation-triangle" />
-          </span>
+          {errors.email && (
+            <span
+              className="icon is-small is-right has-text-danger"
+              data-cy="ErrorIcon"
+            >
+              <i className="fas fa-exclamation-triangle" />
+            </span>
+          )}
         </div>
 
-        <p className="help is-danger" data-cy="ErrorMessage">
-          Email is required
-        </p>
+        {errors.email && (
+          <p className="help is-danger" data-cy="ErrorMessage">
+            {errors.email}
+          </p>
+        )}
       </div>
 
       <div className="field" data-cy="BodyField">
@@ -73,27 +169,41 @@ export const NewCommentForm: React.FC = () => {
         <div className="control">
           <textarea
             id="comment-body"
-            name="body"
+            className={`textarea ${errors.body ? 'is-danger' : ''}`}
+            value={body}
+            onChange={e => {
+              setBody(e.target.value);
+              setErrors(prev => ({ ...prev, body: undefined }));
+            }}
             placeholder="Type comment here"
-            className="textarea is-danger"
           />
         </div>
 
-        <p className="help is-danger" data-cy="ErrorMessage">
-          Enter some text
-        </p>
+        {errors.body && (
+          <p className="help is-danger" data-cy="ErrorMessage">
+            {errors.body}
+          </p>
+        )}
       </div>
 
       <div className="field is-grouped">
         <div className="control">
-          <button type="submit" className="button is-link is-loading">
+          <button
+            type="submit"
+            className={`button is-link ${isSubmitting ? 'is-loading' : ''}`}
+            data-cy="SubmitButton"
+          >
             Add
           </button>
         </div>
 
         <div className="control">
-          {/* eslint-disable-next-line react/button-has-type */}
-          <button type="reset" className="button is-link is-light">
+          <button
+            type="reset"
+            className="button is-light is-link"
+            onClick={handleClear}
+            data-cy="ClearButton"
+          >
             Clear
           </button>
         </div>
diff --git a/src/components/PostDetails.tsx b/src/components/PostDetails.tsx
index 2f82db916..e74e5b178 100644
--- a/src/components/PostDetails.tsx
+++ b/src/components/PostDetails.tsx
@@ -1,106 +1,152 @@
-import React from 'react';
+import React, { useEffect, useState } from 'react';
+import { getCommentsOfPost, deleteComment } from '../utils/api';
+import { Post } from '../types/Post';
+import { Comment } from '../types/Comment';
 import { Loader } from './Loader';
 import { NewCommentForm } from './NewCommentForm';
 
-export const PostDetails: React.FC = () => {
-  return (
-    <div className="content" data-cy="PostDetails">
-      <div className="content" data-cy="PostDetails">
-        <div className="block">
-          <h2 data-cy="PostTitle">
-            #18: voluptate et itaque vero tempora molestiae
-          </h2>
+type Props = {
+  post?: Post | null;
+};
 
-          <p data-cy="PostBody">
-            eveniet quo quis laborum totam consequatur non dolor ut et est
-            repudiandae est voluptatem vel debitis et magnam
-          </p>
-        </div>
+export const PostDetails: React.FC<Props> = ({ post }) => {
+  const [isLoading, setIsLoading] = useState<boolean>(false);
+  const [error, setError] = useState<string | null>(null);
+  const [commentsFromServer, setCommentsFromServer] = useState<Comment[]>([]);
+  const [isFormVisible, setIsFormVisible] = useState<boolean>(false);
+  const [currentPostId, setCurrentPostId] = useState<number | null>(null);
 
-        <div className="block">
-          <Loader />
+  useEffect(() => {
+    const fetchComments = async () => {
+      if (!post?.id) {
+        return;
+      }
 
-          <div className="notification is-danger" data-cy="CommentsError">
-            Something went wrong
-          </div>
+      setIsLoading(true);
+      setError(null);
 
-          <p className="title is-4" data-cy="NoCommentsMessage">
-            No comments yet
-          </p>
+      try {
+        const currentComments = await getCommentsOfPost(post.id);
 
-          <p className="title is-4">Comments:</p>
+        setCommentsFromServer(currentComments);
+      } catch {
+        setError('Failed to load comments. Please try again later.');
+      } finally {
+        setIsLoading(false);
+      }
+    };
 
-          <article className="message is-small" data-cy="Comment">
-            <div className="message-header">
-              <a href="mailto:misha@mate.academy" data-cy="CommentAuthor">
-                Misha Hrynko
-              </a>
-              <button
-                data-cy="CommentDelete"
-                type="button"
-                className="delete is-small"
-                aria-label="delete"
-              >
-                delete button
-              </button>
-            </div>
+    if (post?.id !== currentPostId) {
+      setIsFormVisible(false);
+      setCurrentPostId(post?.id || null);
+      fetchComments();
+    }
+  }, [post, currentPostId]);
+
+  const handleDelete = async (commentId: number) => {
+    const originalComments = [...commentsFromServer];
+
+    setCommentsFromServer(prev =>
+      prev.filter(comment => comment.id !== commentId),
+    );
+    setError(null);
 
-            <div className="message-body" data-cy="CommentBody">
-              Some comment
-            </div>
-          </article>
+    try {
+      await deleteComment(commentId);
+    } catch {
+      setError('Failed to delete comment. Please try again.');
+      setCommentsFromServer(originalComments);
+    }
+  };
 
-          <article className="message is-small" data-cy="Comment">
-            <div className="message-header">
-              <a href="mailto:misha@mate.academy" data-cy="CommentAuthor">
-                Misha Hrynko
-              </a>
+  const handleAddComment = (newComment: Comment) => {
+    setCommentsFromServer(prev => [...prev, newComment]);
+  };
 
+  return (
+    <div className="content" data-cy="PostDetails">
+      <div className="block">
+        <h2 data-cy="PostTitle">{`#${post?.id}: ${post?.title}`}</h2>
+        <p data-cy="PostBody">{post?.body}</p>
+      </div>
+
+      <div className="block">
+        {isLoading ? (
+          <Loader />
+        ) : error ? (
+          <div className="notification is-danger" data-cy="CommentsError">
+            Something went wrong
+          </div>
+        ) : commentsFromServer.length === 0 ? (
+          <>
+            <p className="title is-4" data-cy="NoCommentsMessage">
+              No comments yet
+            </p>
+            {!isFormVisible && (
               <button
-                data-cy="CommentDelete"
+                data-cy="WriteCommentButton"
                 type="button"
-                className="delete is-small"
-                aria-label="delete"
+                className="button is-link"
+                onClick={() => setIsFormVisible(true)}
               >
-                delete button
+                Write a comment
               </button>
-            </div>
-            <div className="message-body" data-cy="CommentBody">
-              One more comment
-            </div>
-          </article>
-
-          <article className="message is-small" data-cy="Comment">
-            <div className="message-header">
-              <a href="mailto:misha@mate.academy" data-cy="CommentAuthor">
-                Misha Hrynko
-              </a>
+            )}
+            {isFormVisible && post?.id && (
+              <NewCommentForm
+                postId={post.id}
+                onCommentAdded={handleAddComment}
+              />
+            )}
+          </>
+        ) : (
+          <>
+            <p className="title is-4">Comments:</p>
+            {commentsFromServer.map(comment => (
+              <article
+                key={comment.id}
+                className="message is-small"
+                data-cy="Comment"
+              >
+                <div className="message-header">
+                  <a href={`mailto:${comment.email}`} data-cy="CommentAuthor">
+                    {comment.name}
+                  </a>
+                  <button
+                    data-cy="CommentDelete"
+                    type="button"
+                    className="delete is-small"
+                    aria-label="delete"
+                    onClick={() => handleDelete(comment.id)}
+                  >
+                    delete button
+                  </button>
+                </div>
+                <div className="message-body" data-cy="CommentBody">
+                  {comment.body}
+                </div>
+              </article>
+            ))}
 
+            {!isFormVisible && (
               <button
-                data-cy="CommentDelete"
+                data-cy="WriteCommentButton"
                 type="button"
-                className="delete is-small"
-                aria-label="delete"
+                className="button is-link"
+                onClick={() => setIsFormVisible(true)}
               >
-                delete button
+                Write a comment
               </button>
-            </div>
-
-            <div className="message-body" data-cy="CommentBody">
-              {'Multi\nline\ncomment'}
-            </div>
-          </article>
-
-          <button
-            data-cy="WriteCommentButton"
-            type="button"
-            className="button is-link"
-          >
-            Write a comment
-          </button>
-        </div>
+            )}
 
-        <NewCommentForm />
+            {isFormVisible && post?.id && (
+              <NewCommentForm
+                postId={post.id}
+                onCommentAdded={handleAddComment}
+              />
+            )}
+          </>
+        )}
       </div>
     </div>
   );
diff --git a/src/components/PostsList.tsx b/src/components/PostsList.tsx
index cf90f04b0..aeb94a046 100644
--- a/src/components/PostsList.tsx
+++ b/src/components/PostsList.tsx
@@ -1,86 +1,68 @@
 import React from 'react';
+import { Post } from '../types/Post';
+import classNames from 'classnames';
+type Props = {
+  posts?: Post[];
+  activePost: Post | null;
+  choosePost: React.Dispatch<React.SetStateAction<Post | null>>;
+};
 
-export const PostsList: React.FC = () => (
-  <div data-cy="PostsList">
-    <p className="title">Posts:</p>
+export const PostsList: React.FC<Props> = ({
+  posts,
+  activePost,
+  choosePost,
+}) => {
+  function handleClickToChoosePost(post: Post) {
+    if (!activePost) {
+      choosePost(post);
+    }
 
-    <table className="table is-fullwidth is-striped is-hoverable is-narrow">
-      <thead>
-        <tr className="has-background-link-light">
-          <th>#</th>
-          <th>Title</th>
-          {/* eslint-disable-next-line jsx-a11y/control-has-associated-label */}
-          <th> </th>
-        </tr>
-      </thead>
+    if (activePost?.id === post.id) {
+      choosePost(null);
+    }
 
-      <tbody>
-        <tr data-cy="Post">
-          <td data-cy="PostId">17</td>
+    if (activePost?.id !== post.id) {
+      choosePost(post);
+    }
+  }
 
-          <td data-cy="PostTitle">
-            fugit voluptas sed molestias voluptatem provident
-          </td>
+  return (
+    <div data-cy="PostsList">
+      <p className="title">Posts:</p>
 
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link is-light"
-            >
-              Open
-            </button>
-          </td>
-        </tr>
+      <table className="table is-fullwidth is-striped is-hoverable is-narrow">
+        <thead>
+          <tr className="has-background-link-light">
+            <th>#</th>
+            <th>Title</th>
+            {/* eslint-disable-next-line jsx-a11y/control-has-associated-label */}
+            <th></th>
+          </tr>
+        </thead>
 
-        <tr data-cy="Post">
-          <td data-cy="PostId">18</td>
+        <tbody>
+          {posts?.map(post => (
+            <tr data-cy="Post" key={post.id}>
+              <td data-cy="PostId">{post.id}</td>
 
-          <td data-cy="PostTitle">
-            voluptate et itaque vero tempora molestiae
-          </td>
+              <td data-cy="PostTitle">{post.title}</td>
 
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link"
-            >
-              Close
-            </button>
-          </td>
-        </tr>
-
-        <tr data-cy="Post">
-          <td data-cy="PostId">19</td>
-          <td data-cy="PostTitle">adipisci placeat illum aut reiciendis qui</td>
-
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link is-light"
-            >
-              Open
-            </button>
-          </td>
-        </tr>
-
-        <tr data-cy="Post">
-          <td data-cy="PostId">20</td>
-          <td data-cy="PostTitle">doloribus ad provident suscipit at</td>
-
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link is-light"
-            >
-              Open
-            </button>
-          </td>
-        </tr>
-      </tbody>
-    </table>
-  </div>
-);
+              <td className="has-text-right is-vcentered">
+                <button
+                  type="button"
+                  data-cy="PostButton"
+                  className={classNames('button', 'is-link', {
+                    'is-light': activePost?.id !== post.id,
+                  })}
+                  onClick={() => handleClickToChoosePost(post)}
+                >
+                  {activePost?.id === post.id ? 'Close' : 'Open'}
+                </button>
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+};
diff --git a/src/components/UserSelector.tsx b/src/components/UserSelector.tsx
index c89442841..44708445f 100644
--- a/src/components/UserSelector.tsx
+++ b/src/components/UserSelector.tsx
@@ -1,17 +1,54 @@
 import React from 'react';
+import { User } from '../types/User';
+import classNames from 'classnames';
+
+type Props = {
+  users: User[] | null;
+  chosenUser: User | null;
+  chooseUser: React.Dispatch<React.SetStateAction<User | null>>;
+};
+
+export const UserSelector: React.FC<Props> = ({
+  users,
+  chosenUser,
+  chooseUser,
+}) => {
+  const [isActive, setIsActive] = React.useState(false);
+
+  const dropdownRef = React.useRef<HTMLDivElement>(null);
+
+  React.useEffect(() => {
+    const handleClickOutside = (event: MouseEvent) => {
+      if (
+        dropdownRef.current &&
+        !dropdownRef.current.contains(event.target as Node)
+      ) {
+        setIsActive(false);
+      }
+    };
+
+    document.addEventListener('click', handleClickOutside);
+
+    return () => {
+      document.removeEventListener('click', handleClickOutside);
+    };
+  }, []);
 
-export const UserSelector: React.FC = () => {
   return (
-    <div data-cy="UserSelector" className="dropdown is-active">
+    <div
+      ref={dropdownRef}
+      data-cy="UserSelector"
+      className={classNames('dropdown', { 'is-active': isActive })}
+    >
       <div className="dropdown-trigger">
         <button
           type="button"
           className="button"
           aria-haspopup="true"
           aria-controls="dropdown-menu"
+          onClick={() => setIsActive(prev => !prev)}
         >
-          <span>Choose a user</span>
-
+          <span>{chosenUser ? chosenUser.name : 'Choose a user'}</span>
           <span className="icon is-small">
             <i className="fas fa-angle-down" aria-hidden="true" />
           </span>
@@ -20,21 +57,21 @@ export const UserSelector: React.FC = () => {
 
       <div className="dropdown-menu" id="dropdown-menu" role="menu">
         <div className="dropdown-content">
-          <a href="#user-1" className="dropdown-item">
-            Leanne Graham
-          </a>
-          <a href="#user-2" className="dropdown-item is-active">
-            Ervin Howell
-          </a>
-          <a href="#user-3" className="dropdown-item">
-            Clementine Bauch
-          </a>
-          <a href="#user-4" className="dropdown-item">
-            Patricia Lebsack
-          </a>
-          <a href="#user-5" className="dropdown-item">
-            Chelsey Dietrich
-          </a>
+          {users?.map(user => (
+            <a
+              key={user.id}
+              href={`#${user.id}`}
+              className={classNames('dropdown-item', {
+                'is-active': user.id === chosenUser?.id,
+              })}
+              onClick={() => {
+                setIsActive(false);
+                chooseUser(user);
+              }}
+            >
+              {user.name}
+            </a>
+          ))}
         </div>
       </div>
     </div>
diff --git a/src/utils/api.ts b/src/utils/api.ts
new file mode 100644
index 000000000..7c1f97beb
--- /dev/null
+++ b/src/utils/api.ts
@@ -0,0 +1,24 @@
+import { client } from './fetchClient';
+import { User } from '../types/User';
+import { Post } from '../types/Post';
+import { Comment } from '../types/Comment';
+
+export const getUsers = () => {
+  return client.get<User[]>(`/users`);
+};
+
+export const getPostsOfUser = (id: number) => {
+  return client.get<Post[]>(`/posts?userId=${id}`);
+};
+
+export const getCommentsOfPost = (id: number) => {
+  return client.get<Comment[]>(`/comments?postId=${id}`);
+};
+
+export const addComment = (newComment: Omit<Comment, 'id'>) => {
+  return client.post<Comment>('/comments', newComment);
+};
+
+export const deleteComment = (id: number) => {
+  return client.delete(`/comments/${id}`);
+};