diff --git a/api_v2/data_interface/tweet.ts b/api_v2/data_interface/tweet.ts
index 3bbef9e..e7c29cc 100644
--- a/api_v2/data_interface/tweet.ts
+++ b/api_v2/data_interface/tweet.ts
@@ -71,3 +71,25 @@ export interface IncludesObject {
   media?: MediaObject[];
   polls?: PollObject;
 }
+
+export interface SelectTweetFields {
+  "attachments"?: boolean;
+  "author_id"?: boolean;
+  "context_annotations"?: boolean;
+  "conversation_id"?: boolean;
+  "created_at"?: boolean;
+  "entities"?: boolean;
+  "geo"?: boolean;
+  "id"?: boolean;
+  "in_reply_to_user_id"?: boolean;
+  "lang"?: boolean;
+  "non_public_metrics"?: boolean;
+  "public_metrics"?: boolean;
+  "organic_metrics"?: boolean;
+  "promoted_metrics"?: boolean;
+  "possibly_sensitive"?: boolean;
+  "referenced_tweets"?: boolean;
+  "source"?: boolean;
+  "text"?: boolean;
+  "withheld"?: boolean;
+}
diff --git a/api_v2/data_interface/user.ts b/api_v2/data_interface/user.ts
index 088a8b8..8a59830 100644
--- a/api_v2/data_interface/user.ts
+++ b/api_v2/data_interface/user.ts
@@ -10,7 +10,7 @@ export interface UserObject {
   entities?: Entities;
   location?: string;
   pinned_tweet_id?: string;
-  profile_image_url: string;
+  profile_image_url?: string;
   protected?: boolean;
   public_metrics?: {
     followers_count: number;
@@ -22,3 +22,21 @@ export interface UserObject {
   verified?: boolean;
   withheld?: WithHeld;
 }
+
+export interface SelectUserFields {
+  "created_at"?: boolean;
+  "description"?: boolean;
+  "entities"?: boolean;
+  "id"?: boolean;
+  "location"?: boolean;
+  "name"?: boolean;
+  "pinned_tweet_id"?: boolean;
+  "profile_image_url"?: boolean;
+  "protected"?: boolean;
+  "public_metrics"?: boolean;
+  "url"?: boolean;
+  "username"?: boolean;
+  "verified"?: boolean;
+  "verified_type"?: boolean;
+  "withheld"?: boolean;
+}
diff --git a/api_v2/users/lookup.ts b/api_v2/users/lookup.ts
new file mode 100644
index 0000000..05ce4e2
--- /dev/null
+++ b/api_v2/users/lookup.ts
@@ -0,0 +1,41 @@
+import { addParamOption, endpoints, getUrl } from "../../util.ts";
+
+import { SelectTweetFields, TweetObject } from "../data_interface/tweet.ts";
+import { SelectUserFields, UserObject } from "../data_interface/user.ts";
+
+interface UsersMeParam {
+  "expansions"?: {
+    "pinned_tweet_id"?: boolean;
+  };
+  "tweet.fields"?: SelectTweetFields;
+  "user.fields"?: SelectUserFields;
+}
+
+interface UsersMeResponse {
+  data: UserObject;
+  includes?: {
+    tweets?: TweetObject[];
+  };
+}
+
+/**
+ * Returns information about an authorized user.
+ *
+ * https://developer.twitter.com/en/docs/twitter-api/users/lookup/api-reference/get-users-me
+ */
+export async function getUsersMe(auth: string, param: UsersMeParam) {
+  const url = getUrl(endpoints.api_v2.users.me);
+  //url.searchParams.set("ids", param.ids);
+  addParamOption(url, param);
+  console.log(url);
+  const res = await (await fetch(
+    url.toString(),
+    {
+      headers: new Headers({
+        "Authorization": `Bearer ${auth}`,
+      }),
+    },
+  )).json();
+
+  return res as UsersMeResponse;
+}
diff --git a/auth/oauth.ts b/auth/oauth.ts
new file mode 100644
index 0000000..741edb6
--- /dev/null
+++ b/auth/oauth.ts
@@ -0,0 +1,124 @@
+import { oAuth1Fetch, OAuth1Info } from "../deps.ts";
+
+import { endpoints, getUrl } from "../util.ts";
+
+type RequestTokenParam = {
+  oauth_callback: string;
+  x_auth_access_type?: "read" | "write";
+};
+type AuthenticationParam = {
+  oauth_token: string;
+  force_login?: boolean;
+  screen_name?: string;
+};
+type AuthorizeParam = AuthenticationParam;
+type AccessTokenParam = {
+  oauth_token: string;
+  oauth_verifier: string;
+};
+
+/**
+ * **Step 1** of the 3-legged OAuth flow and Sign in with Twitter
+ *
+ * Allows a Consumer application to obtain an OAuth Request Token to request user authorization.
+ *
+ * https://developer.twitter.com/en/docs/authentication/api-reference/request_token
+ */
+export async function requestOAuthToken(
+  auth: OAuth1Info,
+  param: RequestTokenParam,
+) {
+  const url = getUrl(endpoints.oauth.requestToken);
+  url.searchParams.set("oauth_callback", param.oauth_callback);
+  if (param.x_auth_access_type) {
+    url.searchParams.set("x_auth_access_type", param.x_auth_access_type);
+  }
+  const res = await oAuth1Fetch(auth, url);
+  if (res.ok === false) {
+    throw new Error("Failed to request OAuth token");
+  }
+
+  const bodyText = await res.text();
+  const bodySp = new URLSearchParams(bodyText);
+  const oauth_token = bodySp.get("oauth_token") as string;
+  const oauth_token_secret = bodySp.get("oauth_token_secret") as string;
+  const oauth_callback_confirmed =
+    bodySp.get("oauth_callback_confirmed") === "true" ? true : false;
+
+  return { oauth_token, oauth_token_secret, oauth_callback_confirmed };
+}
+
+/**
+ * **Step 2** of the 3-legged OAuth flow and Sign in with Twitter
+ *
+ * Allows a Consumer application to use an OAuth Request Tokento request user authorization.
+ *
+ * https://developer.twitter.com/en/docs/authentication/api-reference/authenticate
+ */
+export function getAuthenticateUrl(param: AuthenticationParam) {
+  const url = getUrl(endpoints.oauth.authenticate);
+  url.searchParams.set("oauth_token", param.oauth_token);
+  if (param.force_login !== undefined) {
+    url.searchParams.set("force_login", param.force_login.toString());
+  }
+  if (param.screen_name) {
+    url.searchParams.set("screen_name", param.screen_name);
+  }
+
+  return url;
+}
+
+/**
+ * **Step 2** of the 3-legged OAuth flow and Sign in with Twitter
+ *
+ * Allows a Consumer application to use an OAuth Request Tokento request user authorization.
+ *
+ * https://developer.twitter.com/en/docs/authentication/api-reference/authorize
+ */
+export function getAuthorizeUrl(param: AuthorizeParam) {
+  const url = getUrl(endpoints.oauth.authorize);
+  url.searchParams.set("oauth_token", param.oauth_token);
+  if (param.force_login !== undefined) {
+    url.searchParams.set("force_login", param.force_login.toString());
+  }
+  if (param.screen_name) {
+    url.searchParams.set("screen_name", param.screen_name);
+  }
+
+  return url;
+}
+
+/**
+ * **Step 3** of the 3-legged OAuth flow and Sign in with Twitter
+ *
+ * Allows a Consumer application to exchange the OAuth Request Token for an OAuth Access Token.
+ *
+ * https://developer.twitter.com/en/docs/authentication/api-reference/access_token
+ */
+export async function getOAuthAccessToken(param: AccessTokenParam) {
+  const url = getUrl(endpoints.oauth.accessToken);
+  url.searchParams.set("oauth_token", param.oauth_token);
+  url.searchParams.set("oauth_verifier", param.oauth_verifier);
+
+  const res = await fetch(url);
+  const a = new URLSearchParams(await res.text());
+  const oauth_token = a.get("oauth_token") as string;
+  const oauth_token_secret = a.get("oauth_token_secret") as string;
+  const user_id = a.get("user_id") as string;
+  const screen_name = a.get("screen_name") as string;
+
+  return {
+    oauth_token,
+    oauth_token_secret,
+    user_id,
+    screen_name,
+  };
+}
+
+export async function invalidateOAuthToken(auth: OAuth1Info) {
+  const url = getUrl(endpoints.oauth.invalidateToken);
+  const res = await oAuth1Fetch(auth, url);
+  if (res.ok === false) {
+    throw new Error("invalidateToken failed");
+  }
+}
diff --git a/deps-test.ts b/deps-test.ts
index 9015754..a3106fd 100644
--- a/deps-test.ts
+++ b/deps-test.ts
@@ -1 +1 @@
-export * from "https://deno.land/std@0.165.0/testing/asserts.ts";
+export * from "https://deno.land/std@0.203.0/testing/asserts.ts";
diff --git a/mod.ts b/mod.ts
index 831a701..a6a9fa5 100644
--- a/mod.ts
+++ b/mod.ts
@@ -7,6 +7,8 @@ export * from "./api_v1/tweets/search.ts";
 
 export * from "./api_v2/tweets/filtered_stream.ts";
 export * from "./api_v2/tweets/lookup.ts";
+export * from "./api_v2/users/lookup.ts";
 
+export * from "./auth/oauth.ts";
 export * from "./auth/oauth2.ts";
 export * from "./util.ts";
diff --git a/util.ts b/util.ts
index 1415fbb..a141dbc 100644
--- a/util.ts
+++ b/util.ts
@@ -5,6 +5,13 @@ export const setHost = (url: string) => {
 };
 
 export const endpoints = {
+  oauth: {
+    requestToken: "/oauth/request_token",
+    authenticate: "/oauth/authenticate",
+    authorize: "/oauth/authorize",
+    accessToken: "/oauth/access_token",
+    invalidateToken: "/oauth/invalidate_token",
+  },
   outh2: {
     getToken: "/oauth2/token",
   },
@@ -32,6 +39,9 @@ export const endpoints = {
       rules: "/2/tweets/search/stream/rules",
       connect: "/2/tweets/search/stream",
     },
+    users: {
+      me: "/2/users/me",
+    },
   },
 };