diff --git a/src/App.tsx b/src/App.tsx
index cad8e12c6..7087e19f3 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -3,60 +3,30 @@ import 'bulma/bulma.sass';
 import '@fortawesome/fontawesome-free/css/all.css';
 import './App.scss';
 
-import classNames from 'classnames';
-import { PostsList } from './components/PostsList';
-import { PostDetails } from './components/PostDetails';
 import { UserSelector } from './components/UserSelector';
-import { Loader } from './components/Loader';
+import { SharedProvider } from './SharedContext';
+import { Sidebar } from './components/Sidebar';
+import { MainContent } from './components/MainContent';
 
 export const App: React.FC = () => {
   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">
-                <UserSelector />
-              </div>
-
-              <div className="block" data-cy="MainContent">
-                <p data-cy="NoSelectedUser">No user selected</p>
-
-                <Loader />
-
-                <div
-                  className="notification is-danger"
-                  data-cy="PostsLoadingError"
-                >
-                  Something went wrong!
+    <SharedProvider>
+      <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>
-
-                <div className="notification is-warning" data-cy="NoPostsYet">
-                  No posts yet
-                </div>
-
-                <PostsList />
+                <MainContent />
               </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>
+            <Sidebar />
           </div>
         </div>
-      </div>
-    </main>
+      </main>
+    </SharedProvider>
   );
 };
diff --git a/src/SharedContext.tsx b/src/SharedContext.tsx
new file mode 100644
index 000000000..269728484
--- /dev/null
+++ b/src/SharedContext.tsx
@@ -0,0 +1,208 @@
+import React, {
+  createContext,
+  useCallback,
+  useContext,
+  useEffect,
+  useMemo,
+  useState,
+} from 'react';
+import { SharedContextValue } from './types/ContextValues';
+import { getUsers } from './api/users';
+import { User } from './types/User';
+import { Post } from './types/Post';
+import { getPosts } from './api/posts';
+import { Comment, CommentData } from './types/Comment';
+import { createComment, deleteComment, getComments } from './api/comments';
+
+export const SharedContext = createContext<SharedContextValue | null>(null);
+
+type Props = {
+  children: React.ReactNode;
+};
+
+export const SharedProvider: React.FC<Props> = ({ children }) => {
+  const [users, setUsers] = useState<User[]>([]);
+  const [posts, setPosts] = useState<Post[]>([]);
+  const [comments, setComments] = useState<Comment[]>([]);
+  const [selectedUserId, setSelectedUserId] = useState<number | null>(null);
+  const [selectedPostId, setSelectedPostId] = useState<number | null>(null);
+  const [isLoadingPosts, setIsLoadingPosts] = useState(false);
+  const [isLoadingComments, setIsLoadingComments] = useState(false);
+  const [isSumbitting, setIsSumbitting] = useState(false);
+  const [isError, setIsError] = useState(false);
+
+  const handleCreateComment = useCallback(
+    async ({ name, email, body }: Omit<CommentData, 'postId'>) => {
+      setIsSumbitting(true);
+
+      const trimmedName = name.trim();
+      const trimmedEmail = email.trim();
+      const trimmedBody = body.trim();
+
+      if (trimmedName && trimmedEmail && trimmedBody && selectedPostId) {
+        try {
+          const newComment = await createComment({
+            postId: selectedPostId,
+            name: trimmedName,
+            email: trimmedEmail,
+            body: trimmedBody,
+          });
+
+          setComments(prevComments => [...prevComments, newComment]);
+        } catch {
+          setIsError(true);
+        } finally {
+          setIsSumbitting(false);
+        }
+      }
+    },
+    [selectedPostId, setIsError],
+  );
+
+  const handleDeleteComment = useCallback(
+    async (commentId: number) => {
+      try {
+        await deleteComment(commentId);
+
+        setComments(currentComments =>
+          currentComments.filter(comm => comm.id !== commentId),
+        );
+      } catch {
+        setIsError(true);
+      }
+    },
+    [setIsError],
+  );
+
+  const handleSelectUser = useCallback(
+    async (userId: number) => {
+      setSelectedUserId(userId);
+      setIsLoadingPosts(true);
+
+      try {
+        const loadedPosts = await getPosts(userId);
+
+        setPosts(loadedPosts);
+      } catch {
+        setIsError(true);
+      } finally {
+        setIsLoadingPosts(false);
+      }
+    },
+    [setIsError],
+  );
+
+  const handleSelectPost = useCallback(
+    async (postId: number) => {
+      setSelectedPostId(postId);
+
+      try {
+        const loadedUsers = await getUsers();
+
+        setUsers(loadedUsers);
+      } catch {
+        setIsError(true);
+      }
+    },
+    [setIsError],
+  );
+
+  const handleLoadComments = useCallback(
+    async (postId: number) => {
+      setIsLoadingComments(true);
+      // setIsError(false);
+
+      try {
+        const loadedComments = await getComments(postId);
+
+        setComments(loadedComments);
+      } catch {
+        setIsError(true);
+      } finally {
+        setIsLoadingComments(false);
+      }
+    },
+    [setIsError],
+  );
+
+  const handleClosePostDetails = useCallback(() => {
+    setSelectedPostId(null);
+  }, []);
+
+  const selectedUser = useMemo(
+    () => users?.find(user => user.id === selectedUserId) || null,
+    [users, selectedUserId],
+  );
+
+  const selectedPost = useMemo(
+    () => posts?.find(post => post.id === selectedPostId) || null,
+    [posts, selectedPostId],
+  );
+
+  const sharedValue = useMemo(
+    () => ({
+      users,
+      posts,
+      comments,
+      isError,
+      selectedUser,
+      selectedPost,
+      isLoadingPosts,
+      isLoadingComments,
+      isSumbitting,
+      handleCreateComment,
+      handleDeleteComment,
+      handleLoadComments,
+      handleSelectUser,
+      handleSelectPost,
+      handleClosePostDetails,
+    }),
+    [
+      users,
+      posts,
+      comments,
+      isError,
+      selectedUser,
+      selectedPost,
+      isLoadingPosts,
+      isLoadingComments,
+      isSumbitting,
+      handleCreateComment,
+      handleDeleteComment,
+      handleLoadComments,
+      handleSelectUser,
+      handleSelectPost,
+      handleClosePostDetails,
+    ],
+  );
+
+  useEffect(() => {
+    const fetchUsers = async () => {
+      try {
+        const loadedUsers = await getUsers();
+
+        setUsers(loadedUsers);
+      } catch {
+        setIsError(true);
+      }
+    };
+
+    fetchUsers();
+  }, []);
+
+  return (
+    <SharedContext.Provider value={sharedValue}>
+      {children}
+    </SharedContext.Provider>
+  );
+};
+
+export const useValues = () => {
+  const value = useContext(SharedContext);
+
+  if (!value) {
+    throw new Error('Something is wrong with provider SharedContext');
+  }
+
+  return value;
+};
diff --git a/src/api/comments.ts b/src/api/comments.ts
new file mode 100644
index 000000000..824910a7d
--- /dev/null
+++ b/src/api/comments.ts
@@ -0,0 +1,14 @@
+import { Comment, CommentData } from '../types/Comment';
+import { client } from '../utils/fetchClient';
+
+export const getComments = (postId: number) => {
+  return client.get<Comment[]>(`/comments?postId=${postId}`);
+};
+
+export const createComment = (comment: CommentData) => {
+  return client.post<Comment>(`/comments`, comment);
+};
+
+export const deleteComment = (commentId: number) => {
+  return client.delete(`/comments/${commentId}`);
+};
diff --git a/src/api/posts.ts b/src/api/posts.ts
new file mode 100644
index 000000000..a6a1739ec
--- /dev/null
+++ b/src/api/posts.ts
@@ -0,0 +1,6 @@
+import { Post } from '../types/Post';
+import { client } from '../utils/fetchClient';
+
+export const getPosts = (userId: number) => {
+  return client.get<Post[]>(`/posts?userId=${userId}`);
+};
diff --git a/src/api/users.ts b/src/api/users.ts
new file mode 100644
index 000000000..386bfacd5
--- /dev/null
+++ b/src/api/users.ts
@@ -0,0 +1,6 @@
+import { User } from '../types/User';
+import { client } from '../utils/fetchClient';
+
+export const getUsers = () => {
+  return client.get<User[]>(`/users`);
+};
diff --git a/src/components/CommentsList.tsx b/src/components/CommentsList.tsx
new file mode 100644
index 000000000..a5d8e726b
--- /dev/null
+++ b/src/components/CommentsList.tsx
@@ -0,0 +1,19 @@
+import React from 'react';
+import { useValues } from '../SharedContext';
+import { CommentsListItem } from './CommentsListItem';
+
+export const CommentsList = React.memo(() => {
+  const { comments } = useValues();
+
+  return (
+    <>
+      <p className="title is-4">Comments:</p>
+
+      {comments?.map(comment => (
+        <CommentsListItem key={comment.id} comment={comment} />
+      ))}
+    </>
+  );
+});
+
+CommentsList.displayName = 'CommentsList';
diff --git a/src/components/CommentsListItem.tsx b/src/components/CommentsListItem.tsx
new file mode 100644
index 000000000..fdcf2daa5
--- /dev/null
+++ b/src/components/CommentsListItem.tsx
@@ -0,0 +1,39 @@
+import React from 'react';
+import { Comment } from '../types/Comment';
+import { useValues } from '../SharedContext';
+
+type Props = {
+  comment: Comment;
+};
+
+export const CommentsListItem: React.FC<Props> = ({ comment }) => {
+  const { id, name, email, body } = comment;
+  const { handleDeleteComment } = useValues();
+
+  const handleSubmitDeleteComment = () => {
+    handleDeleteComment(id);
+  };
+
+  return (
+    <article className="message is-small" data-cy="Comment">
+      <div className="message-header">
+        <a href={email} data-cy="CommentAuthor">
+          {name}
+        </a>
+        <button
+          data-cy="CommentDelete"
+          type="button"
+          className="delete is-small"
+          aria-label="delete"
+          onClick={handleSubmitDeleteComment}
+        >
+          delete button
+        </button>
+      </div>
+
+      <div className="message-body" data-cy="CommentBody">
+        {body}
+      </div>
+    </article>
+  );
+};
diff --git a/src/components/MainContent.tsx b/src/components/MainContent.tsx
new file mode 100644
index 000000000..1838d3b65
--- /dev/null
+++ b/src/components/MainContent.tsx
@@ -0,0 +1,37 @@
+import React from 'react';
+import { useValues } from '../SharedContext';
+import { Loader } from './Loader';
+import { PostsList } from './PostsList';
+import { Messages } from './constants/Messages';
+import { Notification } from './Notification';
+
+export const MainContent = () => {
+  const { posts, selectedUser, isLoadingPosts, isError } = useValues();
+
+  let mainContent: React.JSX.Element;
+
+  if (isLoadingPosts) {
+    mainContent = <Loader />;
+  } else if (!selectedUser) {
+    mainContent = <p data-cy="NoSelectedUser">No user selected</p>;
+  } else if (isError) {
+    mainContent = (
+      <Notification
+        errorMessage={Messages.commentsError}
+        dataCy={'PostsLoadingError'}
+      />
+    );
+  } else if (!posts.length) {
+    mainContent = (
+      <Notification errorMessage={Messages.noPostsYet} dataCy={'NoPostsYet'} />
+    );
+  } else {
+    mainContent = <PostsList />;
+  }
+
+  return (
+    <div className="block" data-cy="MainContent">
+      {mainContent}
+    </div>
+  );
+};
diff --git a/src/components/NewCommentForm.tsx b/src/components/NewCommentForm.tsx
index 73a8a0b45..a9034bbba 100644
--- a/src/components/NewCommentForm.tsx
+++ b/src/components/NewCommentForm.tsx
@@ -1,99 +1,211 @@
-import React from 'react';
+import React, { useReducer, useState } from 'react';
+import { useValues } from '../SharedContext';
+import cn from 'classnames';
+import { Messages } from './constants/Messages';
+
+type Action =
+  | { type: 'changeName'; payload: { newName: string } }
+  | { type: 'changeEmail'; payload: { newEmail: string } }
+  | { type: 'changeBody'; payload: { newBody: string } };
+
+interface State {
+  name: string;
+  email: string;
+  body: string;
+}
+
+function reducer(state: State, action: Action): State {
+  switch (action.type) {
+    case 'changeName':
+      return { ...state, name: action.payload.newName };
+    case 'changeEmail':
+      return { ...state, email: action.payload.newEmail };
+    case 'changeBody':
+      return { ...state, body: action.payload.newBody };
+    default:
+      return state;
+  }
+}
+
+const initialValue: State = {
+  name: '',
+  email: '',
+  body: '',
+};
 
 export const NewCommentForm: React.FC = () => {
+  const { isSumbitting, handleCreateComment } = useValues();
+  const [state, dispatch] = useReducer(reducer, initialValue);
+  const [errors, setErrors] = useState({
+    name: '',
+    email: '',
+    body: '',
+  });
+
+  const { name, email, body } = state;
+
+  const handleChangeName = (newName: string) => {
+    dispatch({ type: 'changeName', payload: { newName } });
+    setErrors(prevErrors => ({ ...prevErrors, name: '' }));
+  };
+
+  const handleChangeEmail = (newEmail: string) => {
+    dispatch({ type: 'changeEmail', payload: { newEmail } });
+    setErrors(prevErrors => ({ ...prevErrors, email: '' }));
+  };
+
+  const handleChangeText = (newBody: string) => {
+    dispatch({ type: 'changeBody', payload: { newBody } });
+    setErrors(prevErrors => ({ ...prevErrors, body: '' }));
+  };
+
+  const reset = () => {
+    dispatch({ type: 'changeBody', payload: { newBody: '' } });
+  };
+
+  const handleSubmitNewComment = async (event: React.FormEvent) => {
+    event.preventDefault();
+
+    const newErrors = { name: '', email: '', body: '' };
+
+    if (!name.trim().length) {
+      newErrors.name = Messages.nameRequiredMessage;
+    }
+
+    if (!email.trim().length) {
+      newErrors.email = Messages.emailRequiredMessage;
+    }
+
+    if (!body.trim().length) {
+      newErrors.body = Messages.bodyRequiredMessage;
+    }
+
+    setErrors(newErrors);
+
+    if (Object.values(newErrors).some(err => err)) {
+      return;
+    }
+
+    try {
+      await handleCreateComment({ name, email, body });
+
+      reset();
+    } catch { }
+  };
+
+  const handleResetButton = () => {
+    dispatch({ type: 'changeName', payload: { newName: '' } });
+    dispatch({ type: 'changeEmail', payload: { newEmail: '' } });
+    dispatch({ type: 'changeBody', payload: { newBody: '' } });
+    setErrors({ name: '', email: '', body: '' });
+  };
+
   return (
-    <form data-cy="NewCommentForm">
+    <form data-cy="NewCommentForm" onSubmit={handleSubmitNewComment}>
       <div className="field" data-cy="NameField">
         <label className="label" htmlFor="comment-author-name">
           Author Name
         </label>
-
         <div className="control has-icons-left has-icons-right">
           <input
             type="text"
             name="name"
             id="comment-author-name"
             placeholder="Name Surname"
-            className="input is-danger"
+            className={cn('input', { 'is-danger': errors.name })}
+            value={name}
+            onChange={e => handleChangeName(e.target.value)}
           />
-
           <span className="icon is-small is-left">
             <i className="fas fa-user" />
           </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
         </label>
-
         <div className="control has-icons-left has-icons-right">
           <input
-            type="text"
+            type="email"
             name="email"
             id="comment-author-email"
             placeholder="email@test.com"
-            className="input is-danger"
+            className={cn('input', { 'is-danger': errors.email })}
+            value={email}
+            onChange={e => handleChangeEmail(e.target.value)}
           />
-
           <span className="icon is-small is-left">
             <i className="fas fa-envelope" />
           </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">
         <label className="label" htmlFor="comment-body">
           Comment Text
         </label>
-
         <div className="control">
           <textarea
             id="comment-body"
             name="body"
             placeholder="Type comment here"
-            className="textarea is-danger"
+            className={cn('textarea', { 'is-danger': errors.body })}
+            value={body}
+            onChange={e => handleChangeText(e.target.value)}
           />
         </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={cn('button', 'is-link', {
+              'is-loading': isSumbitting,
+            })}
+          >
             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-link is-light"
+            onClick={handleResetButton}
+          >
             Clear
           </button>
         </div>
diff --git a/src/components/Notification/Notification.tsx b/src/components/Notification/Notification.tsx
new file mode 100644
index 000000000..40bb6317d
--- /dev/null
+++ b/src/components/Notification/Notification.tsx
@@ -0,0 +1,20 @@
+import React from 'react';
+import { useValues } from '../../SharedContext';
+
+type Props = {
+  errorMessage: string;
+  dataCy: string;
+};
+
+export const Notification: React.FC<Props> = ({ errorMessage, dataCy }) => {
+  const { isError } = useValues();
+
+  return (
+    <div
+      className={`notification ${isError ? 'is-danger' : 'is-warning'}`}
+      data-cy={dataCy}
+    >
+      {errorMessage}
+    </div>
+  );
+};
diff --git a/src/components/Notification/index.ts b/src/components/Notification/index.ts
new file mode 100644
index 000000000..ed80171ae
--- /dev/null
+++ b/src/components/Notification/index.ts
@@ -0,0 +1 @@
+export * from './Notification';
diff --git a/src/components/PostDetails.tsx b/src/components/PostDetails.tsx
index 2f82db916..f405b9302 100644
--- a/src/components/PostDetails.tsx
+++ b/src/components/PostDetails.tsx
@@ -1,106 +1,97 @@
-import React from 'react';
+import React, { useEffect, useState } from 'react';
+import { useValues } from '../SharedContext';
+import { Post } from '../types/Post';
 import { Loader } from './Loader';
 import { NewCommentForm } from './NewCommentForm';
+import { Notification } from './Notification';
+import { Messages } from './constants/Messages';
+
+interface Props {
+  post: Post;
+}
+
+export const PostDetails: React.FC<Props> = ({ post }) => {
+  const {
+    comments,
+    isLoadingComments,
+    isError,
+    handleLoadComments,
+    handleDeleteComment,
+  } = useValues();
+  const [isCommenting, setIsCommenting] = useState(false);
+
+  useEffect(() => {
+    handleLoadComments(post.id);
+    setIsCommenting(false);
+  }, [post.id, handleLoadComments]);
 
-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>
+          <h2 data-cy="PostTitle">{`#${post.id}: ${post.title}`}</h2>
 
-          <p data-cy="PostBody">
-            eveniet quo quis laborum totam consequatur non dolor ut et est
-            repudiandae est voluptatem vel debitis et magnam
-          </p>
+          <p data-cy="PostBody">{post.body}</p>
         </div>
-
         <div className="block">
-          <Loader />
-
-          <div className="notification is-danger" data-cy="CommentsError">
-            Something went wrong
-          </div>
-
-          <p className="title is-4" data-cy="NoCommentsMessage">
-            No comments yet
-          </p>
-
-          <p className="title is-4">Comments:</p>
-
-          <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>
-
-            <div className="message-body" data-cy="CommentBody">
-              Some 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>
-
-              <button
-                data-cy="CommentDelete"
-                type="button"
-                className="delete is-small"
-                aria-label="delete"
-              >
-                delete button
-              </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>
-
-              <button
-                data-cy="CommentDelete"
-                type="button"
-                className="delete is-small"
-                aria-label="delete"
-              >
-                delete button
-              </button>
-            </div>
+          {isError && (
+            <Notification
+              errorMessage={Messages.commentsError}
+              dataCy={'CommentsError'}
+            />
+          )}
 
-            <div className="message-body" data-cy="CommentBody">
-              {'Multi\nline\ncomment'}
-            </div>
-          </article>
+          {isLoadingComments ? (
+            <Loader />
+          ) : !comments.length && !isError ? (
+            <Notification
+              errorMessage={Messages.noCommentsMessage}
+              dataCy={'NoCommentsMessage'}
+            />
+          ) : (
+            <>
+              <p className="title is-4">Comments:</p>
+              {comments.map(({ id, email, name, body }) => (
+                <article
+                  className="message is-small"
+                  key={id}
+                  data-cy="Comment"
+                >
+                  <div className="message-header">
+                    <a href={`mailto:${email}`} data-cy="CommentAuthor">
+                      {name}
+                    </a>
+                    <button
+                      data-cy="CommentDelete"
+                      type="button"
+                      className="delete is-small"
+                      aria-label="delete"
+                      onClick={() => handleDeleteComment(id)}
+                    >
+                      delete button
+                    </button>
+                  </div>
+                  <div className="message-body" data-cy="CommentBody">
+                    {body}
+                  </div>
+                </article>
+              ))}
+            </>
+          )}
 
-          <button
-            data-cy="WriteCommentButton"
-            type="button"
-            className="button is-link"
-          >
-            Write a comment
-          </button>
+          {!isCommenting && !isLoadingComments && !isError && (
+            <button
+              data-cy="WriteCommentButton"
+              type="button"
+              className="button is-link"
+              onClick={() => setIsCommenting(true)}
+            >
+              Write a comment
+            </button>
+          )}
         </div>
 
-        <NewCommentForm />
+        {isCommenting && !isLoadingComments && !isError && <NewCommentForm />}
       </div>
     </div>
   );
diff --git a/src/components/PostsList.tsx b/src/components/PostsList.tsx
index cf90f04b0..0a0feb9f3 100644
--- a/src/components/PostsList.tsx
+++ b/src/components/PostsList.tsx
@@ -1,86 +1,28 @@
 import React from 'react';
-
-export const PostsList: React.FC = () => (
-  <div data-cy="PostsList">
-    <p className="title">Posts:</p>
-
-    <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>
-
-      <tbody>
-        <tr data-cy="Post">
-          <td data-cy="PostId">17</td>
-
-          <td data-cy="PostTitle">
-            fugit voluptas sed molestias voluptatem provident
-          </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">18</td>
-
-          <td data-cy="PostTitle">
-            voluptate et itaque vero tempora molestiae
-          </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>
-);
+import { useValues } from '../SharedContext';
+import { PostsListItem } from './PostsListItem';
+
+export const PostsList: React.FC = () => {
+  const { posts } = useValues();
+
+  return (
+    <div data-cy="PostsList">
+      <p className="title">Posts:</p>
+
+      <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>
+
+        <tbody>
+          {posts?.map(post => <PostsListItem key={post.id} post={post} />)}
+        </tbody>
+      </table>
+    </div>
+  );
+};
diff --git a/src/components/PostsListItem.tsx b/src/components/PostsListItem.tsx
new file mode 100644
index 000000000..820f7850f
--- /dev/null
+++ b/src/components/PostsListItem.tsx
@@ -0,0 +1,46 @@
+import React from 'react';
+import { Post } from '../types/Post';
+import { useValues } from '../SharedContext';
+import cn from 'classnames';
+
+type Props = {
+  post: Post;
+};
+
+export const PostsListItem: React.FC<Props> = ({ post }) => {
+  const { id, title } = post;
+  const { selectedPost, handleSelectPost, handleClosePostDetails } =
+    useValues();
+
+  const isSelected = selectedPost?.id !== id;
+
+  const handleButtonClick = () =>
+    isSelected ? handleSelectPost(id) : handleClosePostDetails();
+
+  return (
+    <tr data-cy="Post">
+      <td data-cy="PostId">{id}</td>
+
+      <td data-cy="PostTitle">{title}</td>
+
+      <td className="has-text-right is-vcentered">
+        {
+          <button
+            type="button"
+            data-cy="PostButton"
+            className={cn(
+              'button is-link',
+              {
+                'is-light': isSelected,
+              },
+              { 'is-focus': !isSelected },
+            )}
+            onClick={handleButtonClick}
+          >
+            {isSelected ? 'Open' : 'Close'}
+          </button>
+        }
+      </td>
+    </tr>
+  );
+};
diff --git a/src/components/Sidebar.tsx b/src/components/Sidebar.tsx
new file mode 100644
index 000000000..6a891a7d0
--- /dev/null
+++ b/src/components/Sidebar.tsx
@@ -0,0 +1,21 @@
+import cn from 'classnames';
+import React from 'react';
+import { useValues } from '../SharedContext';
+import { PostDetails } from './PostDetails';
+
+export const Sidebar: React.FC = () => {
+  const { selectedPost } = useValues();
+
+  return (
+    <div
+      data-cy="Sidebar"
+      className={cn('tile', 'is-parent', 'is-8-desktop', 'Sidebar', {
+        'Sidebar--open': selectedPost,
+      })}
+    >
+      <div className="tile is-child box is-success ">
+        {selectedPost && <PostDetails post={selectedPost} />}
+      </div>
+    </div>
+  );
+};
diff --git a/src/components/UserSelector.tsx b/src/components/UserSelector.tsx
index c89442841..3b3e99bd3 100644
--- a/src/components/UserSelector.tsx
+++ b/src/components/UserSelector.tsx
@@ -1,16 +1,37 @@
-import React from 'react';
+import React, { useState } from 'react';
+import { useValues } from '../SharedContext';
+import cn from 'classnames';
+import { UserSelectorItem } from './UserSelectorItem';
 
 export const UserSelector: React.FC = () => {
+  const { users, selectedUser } = useValues();
+  const [isActiveUserSelector, setIsActiveUserSelector] = useState(false);
+
+  const handleToggleDropDown = () => {
+    setIsActiveUserSelector(!isActiveUserSelector);
+  };
+
+  const handleCloseOpenMenu = () => {
+    setIsActiveUserSelector(false);
+  };
+
   return (
-    <div data-cy="UserSelector" className="dropdown is-active">
+    <div
+      data-cy="UserSelector"
+      className={cn('dropdown', {
+        'is-active': isActiveUserSelector === true,
+      })}
+    >
       <div className="dropdown-trigger">
         <button
           type="button"
           className="button"
           aria-haspopup="true"
           aria-controls="dropdown-menu"
+          onClick={handleToggleDropDown}
+          onBlur={handleCloseOpenMenu}
         >
-          <span>Choose a user</span>
+          <span>{selectedUser?.name || 'Choose a user'}</span>
 
           <span className="icon is-small">
             <i className="fas fa-angle-down" aria-hidden="true" />
@@ -20,21 +41,13 @@ 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 => (
+            <UserSelectorItem
+              user={user}
+              key={user.id}
+              setIsActiveUserSelector={setIsActiveUserSelector}
+            />
+          ))}
         </div>
       </div>
     </div>
diff --git a/src/components/UserSelectorItem.tsx b/src/components/UserSelectorItem.tsx
new file mode 100644
index 000000000..db5e8c43c
--- /dev/null
+++ b/src/components/UserSelectorItem.tsx
@@ -0,0 +1,39 @@
+import React from 'react';
+import { User } from '../types/User';
+import { useValues } from '../SharedContext';
+import cn from 'classnames';
+
+type Props = {
+  user: User;
+  setIsActiveUserSelector: (status: boolean) => void;
+};
+
+export const UserSelectorItem: React.FC<Props> = ({
+  user,
+  setIsActiveUserSelector,
+}) => {
+  const { id, name } = user;
+  const { selectedUser, handleSelectUser } = useValues();
+
+  const handleSubmitSelectUser = () => {
+    handleSelectUser(id);
+    setIsActiveUserSelector(false);
+  };
+
+  const handleMouseDownClick = (event: React.MouseEvent<HTMLAnchorElement>) => {
+    event.preventDefault();
+  };
+
+  return (
+    <a
+      href={`#user-${id}`}
+      className={cn('dropdown-item', {
+        'is-active': selectedUser?.id === id,
+      })}
+      onClick={handleSubmitSelectUser}
+      onMouseDown={handleMouseDownClick}
+    >
+      {name}
+    </a>
+  );
+};
diff --git a/src/components/constants/Messages.ts b/src/components/constants/Messages.ts
new file mode 100644
index 000000000..6cb94bace
--- /dev/null
+++ b/src/components/constants/Messages.ts
@@ -0,0 +1,9 @@
+export const Messages = {
+  postsLoadingError: 'Something went wrong!',
+  noPostsYet: 'No posts yet',
+  commentsError: 'Something went wrong',
+  noCommentsMessage: 'No comments yet',
+  nameRequiredMessage: 'Name is required',
+  emailRequiredMessage: 'Email is required',
+  bodyRequiredMessage: 'Enter some text',
+};
diff --git a/src/types/Comment.ts b/src/types/Comment.ts
index 61c98619c..a45c2563d 100644
--- a/src/types/Comment.ts
+++ b/src/types/Comment.ts
@@ -6,4 +6,4 @@ export interface Comment {
   body: string;
 }
 
-export type CommentData = Pick<Comment, 'name' | 'email' | 'body'>;
+export type CommentData = Pick<Comment, 'postId' | 'name' | 'email' | 'body'>;
diff --git a/src/types/ContextValues.ts b/src/types/ContextValues.ts
new file mode 100644
index 000000000..73f657089
--- /dev/null
+++ b/src/types/ContextValues.ts
@@ -0,0 +1,29 @@
+import { Comment } from './Comment';
+import {
+  HandleClosePostDetails,
+  HandleCreateComment,
+  HandleDeleteComment,
+  HandleLoadComments,
+  HandleSelectPost,
+  HandleSelectUser,
+} from './HandlerFunctions';
+import { Post } from './Post';
+import { User } from './User';
+
+export type SharedContextValue = {
+  users: User[];
+  posts: Post[];
+  comments: Comment[];
+  isError: boolean;
+  selectedUser: User | null;
+  selectedPost: Post | null;
+  isLoadingPosts: boolean;
+  isLoadingComments: boolean;
+  isSumbitting: boolean;
+  handleCreateComment: HandleCreateComment;
+  handleDeleteComment: HandleDeleteComment;
+  handleLoadComments: HandleLoadComments;
+  handleSelectUser: HandleSelectUser;
+  handleSelectPost: HandleSelectPost;
+  handleClosePostDetails: HandleClosePostDetails;
+};
diff --git a/src/types/HandlerFunctions.ts b/src/types/HandlerFunctions.ts
new file mode 100644
index 000000000..bd51b6cd2
--- /dev/null
+++ b/src/types/HandlerFunctions.ts
@@ -0,0 +1,10 @@
+import { CommentData } from './Comment';
+
+export type HandleCreateComment = (
+  comment: Omit<CommentData, 'postId'>,
+) => void;
+export type HandleDeleteComment = (commentId: number) => void;
+export type HandleLoadComments = (postId: number) => void;
+export type HandleSelectUser = (userId: number) => void;
+export type HandleSelectPost = (postId: number) => void;
+export type HandleClosePostDetails = () => void;