diff --git a/examples/general/api-tokens.ts b/examples/general/api-tokens.ts
index 68701a1..f49c6ab 100644
--- a/examples/general/api-tokens.ts
+++ b/examples/general/api-tokens.ts
@@ -19,8 +19,12 @@ async function apiTokensFlow() {
 
     // Create a new API token scoped to specific resources.
     // The full `token` value is returned only in this response — store it securely.
+    // `expires_at` is optional: omit it for the server default (a 1-year default
+    // is being rolled out), pass an ISO 8601 date-time for a custom expiration,
+    // or pass `null` for a token that never expires.
     const created = await apiTokensClient.create({
       name: "My token",
+      expires_at: "2027-06-01T00:00:00Z",
       resources: [
         { resource_type: "account", resource_id: Number(ACCOUNT_ID), access_level: 10 },
       ],
@@ -36,6 +40,8 @@ async function apiTokensFlow() {
 
     // Reset the API token: expires the existing token and returns a new one
     // with the same permissions. The new `token` value is only returned here.
+    // Like create, reset accepts an optional `expires_at` for the new token,
+    // e.g. `reset(tokenId, { expires_at: null })` for a token that never expires.
     const reset = await apiTokensClient.reset(tokenId);
     console.log("Reset API token:", JSON.stringify(reset, null, 2));
     console.log("New token value (store securely):", reset.token);
diff --git a/src/__tests__/lib/api/resources/ApiTokens.test.ts b/src/__tests__/lib/api/resources/ApiTokens.test.ts
index bc127f5..5ee22a0 100644
--- a/src/__tests__/lib/api/resources/ApiTokens.test.ts
+++ b/src/__tests__/lib/api/resources/ApiTokens.test.ts
@@ -130,6 +130,73 @@ describe("lib/api/resources/ApiTokens: ", () => {
       expect(result).toEqual(responseData);
     });
 
+    it("omits expires_at from the request body when not provided.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens`;
+
+      expect.assertions(1);
+
+      mock.onPost(endpoint).reply(200, responseData);
+      await apiTokensAPI.create(params);
+
+      expect("expires_at" in JSON.parse(mock.history.post[0].data)).toEqual(
+        false
+      );
+    });
+
+    it("sends expires_at when provided.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens`;
+      const expiresAt = "2027-06-01T00:00:00Z";
+
+      expect.assertions(1);
+
+      mock
+        .onPost(endpoint)
+        .reply(200, { ...responseData, expires_at: expiresAt });
+      await apiTokensAPI.create({ ...params, expires_at: expiresAt });
+
+      expect(JSON.parse(mock.history.post[0].data).expires_at).toEqual(
+        expiresAt
+      );
+    });
+
+    it("sends explicit null expires_at for a token that never expires.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens`;
+
+      expect.assertions(2);
+
+      mock.onPost(endpoint).reply(200, responseData);
+      await apiTokensAPI.create({ ...params, expires_at: null });
+
+      const body = JSON.parse(mock.history.post[0].data);
+
+      expect("expires_at" in body).toEqual(true);
+      expect(body.expires_at).toBeNull();
+    });
+
+    it("fails with error when the server rejects expires_at.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens`;
+      const expectedErrorMessage = "expires_at: must not be in the past";
+
+      expect.assertions(2);
+
+      mock
+        .onPost(endpoint)
+        .reply(422, { errors: { expires_at: ["must not be in the past"] } });
+
+      try {
+        await apiTokensAPI.create({
+          ...params,
+          expires_at: "2020-01-01T00:00:00Z",
+        });
+      } catch (error) {
+        expect(error).toBeInstanceOf(MailtrapError);
+
+        if (error instanceof MailtrapError) {
+          expect(error.message).toEqual(expectedErrorMessage);
+        }
+      }
+    });
+
     it("fails with error.", async () => {
       const expectedErrorMessage = "Request failed with status code 404";
 
@@ -223,6 +290,70 @@ describe("lib/api/resources/ApiTokens: ", () => {
       expect(result).toEqual(responseData);
     });
 
+    it("sends no request body when params are omitted.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens/${tokenId}/reset`;
+
+      expect.assertions(1);
+
+      mock.onPost(endpoint).reply(200, responseData);
+      await apiTokensAPI.reset(tokenId);
+
+      expect(mock.history.post[0].data).toBeUndefined();
+    });
+
+    it("sends expires_at in the request body when provided.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens/${tokenId}/reset`;
+      const expiresAt = "2027-06-01T00:00:00Z";
+
+      expect.assertions(1);
+
+      mock
+        .onPost(endpoint)
+        .reply(200, { ...responseData, expires_at: expiresAt });
+      await apiTokensAPI.reset(tokenId, { expires_at: expiresAt });
+
+      expect(JSON.parse(mock.history.post[0].data)).toEqual({
+        expires_at: expiresAt,
+      });
+    });
+
+    it("sends explicit null expires_at for a token that never expires.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens/${tokenId}/reset`;
+
+      expect.assertions(2);
+
+      mock.onPost(endpoint).reply(200, responseData);
+      await apiTokensAPI.reset(tokenId, { expires_at: null });
+
+      const body = JSON.parse(mock.history.post[0].data);
+
+      expect("expires_at" in body).toEqual(true);
+      expect(body.expires_at).toBeNull();
+    });
+
+    it("fails with error when the server rejects expires_at.", async () => {
+      const endpoint = `${GENERAL_ENDPOINT}/api/accounts/${accountId}/api_tokens/${tokenId}/reset`;
+      const expectedErrorMessage = "expires_at: must not be in the past";
+
+      expect.assertions(2);
+
+      mock
+        .onPost(endpoint)
+        .reply(422, { errors: { expires_at: ["must not be in the past"] } });
+
+      try {
+        await apiTokensAPI.reset(tokenId, {
+          expires_at: "2020-01-01T00:00:00Z",
+        });
+      } catch (error) {
+        expect(error).toBeInstanceOf(MailtrapError);
+
+        if (error instanceof MailtrapError) {
+          expect(error.message).toEqual(expectedErrorMessage);
+        }
+      }
+    });
+
     it("fails with error.", async () => {
       const expectedErrorMessage = "Request failed with status code 404";
 
diff --git a/src/lib/api/resources/ApiTokens.ts b/src/lib/api/resources/ApiTokens.ts
index 205c30e..049618f 100644
--- a/src/lib/api/resources/ApiTokens.ts
+++ b/src/lib/api/resources/ApiTokens.ts
@@ -5,6 +5,7 @@ import {
   ApiToken,
   ApiTokenWithToken,
   CreateApiTokenRequest,
+  ResetApiTokenRequest,
 } from "../../../types/api/api-tokens";
 
 const { CLIENT_SETTINGS } = CONFIG;
@@ -33,6 +34,9 @@ export default class ApiTokensApi {
   /**
    * Create a new API token for the account with the given name and resource permissions.
    * The full token value is returned only in the response of this call — store it securely.
+   * Unless `expires_at` is provided, the token expiration falls back to the server
+   * default (a 1-year default is being rolled out); pass `expires_at: null` for a
+   * token that never expires.
    */
   public async create(params: CreateApiTokenRequest) {
     const url = this.apiTokensURL;
@@ -54,10 +58,20 @@ export default class ApiTokensApi {
    * Reset an API token: expires the existing token and returns a new one with
    * the same permissions. The new token value is returned only in this response —
    * store it securely. Only tokens that have not already been reset can be reset.
+   * Unless `expires_at` is provided, the new token expiration falls back to the
+   * server default (a 1-year default is being rolled out); pass `expires_at: null`
+   * for a token that never expires.
    */
-  public async reset(id: number) {
+  public async reset(id: number, params?: ResetApiTokenRequest) {
     const url = `${this.apiTokensURL}/${id}/reset`;
 
+    if (params && "expires_at" in params) {
+      return this.client.post<ApiTokenWithToken, ApiTokenWithToken>(
+        url,
+        params
+      );
+    }
+
     return this.client.post<ApiTokenWithToken, ApiTokenWithToken>(url);
   }
 
diff --git a/src/types/api/api-tokens.ts b/src/types/api/api-tokens.ts
index 472b0f2..1651898 100644
--- a/src/types/api/api-tokens.ts
+++ b/src/types/api/api-tokens.ts
@@ -16,6 +16,13 @@ export type ResourcePermission = {
 
 export type CreateApiTokenRequest = {
   name: string;
+  /**
+   * Optional token expiration as an ISO 8601 date-time.
+   * Omit for the server default (a 1-year default is being rolled out).
+   * Pass explicit `null` for a token that never expires.
+   * Past or more-than-5-years-ahead values are rejected with 422.
+   */
+  expires_at?: string | null;
   resources?: ResourcePermissionInput[];
 };
 
@@ -31,3 +38,13 @@ export type ApiToken = {
 export type ApiTokenWithToken = ApiToken & {
   token: string;
 };
+
+export type ResetApiTokenRequest = {
+  /**
+   * Optional expiration for the new token as an ISO 8601 date-time.
+   * Omit for the server default (a 1-year default is being rolled out).
+   * Pass explicit `null` for a token that never expires.
+   * Past or more-than-5-years-ahead values are rejected with 422.
+   */
+  expires_at?: string | null;
+};