diff --git a/types/openid-client/index.d.ts b/types/openid-client/index.d.ts
index 805091997b..51cc2eeb1f 100644
--- a/types/openid-client/index.d.ts
+++ b/types/openid-client/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/panva/node-openid-client
 // Definitions by: ulrichb <https://github.com/ulrichb>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 3.0
 
 /// <reference types="node" />
 
@@ -20,6 +20,8 @@ export class Issuer {
     readonly metadata: IssuerMetadata;
 
     readonly Client: typeof Client;
+
+    keystore(forceReload?: boolean): Promise<unknown>;
 }
 
 export interface ClientMetadata {
@@ -68,6 +70,14 @@ export class Client {
     }): Promise<TokenSet>;
 
     userinfo(accessToken: string | TokenSet): Promise<{ readonly [name: string]: {} | null | undefined }>;
+
+    grant(body: {
+        readonly grant_type: "authorization_code" | "client_credentials" | "password" | "refresh_token" | string;
+        readonly [name: string]: string | undefined;
+    }): Promise<TokenSet>;
+
+    introspect(token: string, tokenTypeHint?: string, extras?: { readonly introspectBody?: {} }):
+        Promise<{ readonly [name: string]: {} | null | undefined }>;
 }
 
 export class TokenSet {
diff --git a/types/openid-client/openid-client-tests.ts b/types/openid-client/openid-client-tests.ts
index cf5a8e631f..7557c42b13 100644
--- a/types/openid-client/openid-client-tests.ts
+++ b/types/openid-client/openid-client-tests.ts
@@ -5,6 +5,11 @@ async (req: IncomingMessage) => {
     const issuer = await Issuer.discover('https://accounts.google.com');
     console.log('Discovered issuer %O', issuer.metadata.issuer);
 
+    issuer.keystore();
+    issuer.keystore(true);
+
+    //
+
     const client = new issuer.Client({
         client_id: 'c',
         client_secret: 's',
@@ -13,10 +18,14 @@ async (req: IncomingMessage) => {
     });
     console.log(client.metadata.client_id);
 
+    //
+
     const code_verifier = generators.codeVerifier();
 
     const code_challenge = generators.codeChallenge(code_verifier);
 
+    //
+
     client.authorizationUrl({
         scope: 'openid email profile',
         response_mode: 'form_post',
@@ -26,14 +35,38 @@ async (req: IncomingMessage) => {
         code_challenge_method: 'S256',
     }).substring(0);
 
+    //
+
     const params = client.callbackParams(req);
-    const tokenSet = await client.callback('https://client.example.com/callback', params, { code_verifier });
-    console.log(tokenSet.id_token, tokenSet.access_token, tokenSet.refresh_token);
-    console.log(tokenSet.expired(), tokenSet.claims()["some claim name"]);
+    const callbackResponse = await client.callback('https://client.example.com/callback', params, { code_verifier });
+    console.log(callbackResponse.id_token, callbackResponse.access_token, callbackResponse.refresh_token);
+    console.log(callbackResponse.expired(), callbackResponse.claims()["some claim name"]);
+
+    //
 
     await client.userinfo("access token");
-    const userinfo = await client.userinfo(tokenSet);
+    const userinfo = await client.userinfo(callbackResponse);
     console.log(userinfo["some user info name"]);
 
+    //
+
+    const grantResponse = await client.grant({
+        grant_type: "client_credentials",
+        acr_values: "acr_values",
+    });
+    console.log(grantResponse.access_token);
+
+    //
+
+    const introspectResponse = await client.introspect("token");
+    console.log(introspectResponse["some claim name"]);
+
+    client.introspect("token", "tokenTypeHint");
+
+    client.introspect("token", "tokenTypeHint", {});
+    client.introspect("token", "tokenTypeHint", { introspectBody: {} });
+
+    //
+
     client.endSessionUrl({ id_token_hint: "id_token_hint" }).substring(0);
 };