diff --git a/packages/jsdoc-core/lib/api.js b/packages/jsdoc-core/lib/api.js
index 0939aa28..c888b445 100644
--- a/packages/jsdoc-core/lib/api.js
+++ b/packages/jsdoc-core/lib/api.js
@@ -20,6 +20,8 @@ import path from 'node:path';
 import { Env } from '@jsdoc/core';
 import glob from 'fast-glob';
 
+const DEFAULT_TEMPLATE = '@jsdoc/template-legacy';
+
 /**
  * The API for programmatically generating documentation with JSDoc.
  *
@@ -38,10 +40,14 @@ export default class Api {
   constructor(opts) {
     /**
      * An event emitter that acts as a message bus for all JSDoc modules.
+     *
+     * @type {node:events.EventEmitter}
      */
     this.emitter = opts?.emitter ?? new EventEmitter();
     /**
      * The JSDoc environment, including configuration settings, for this API instance.
+     *
+     * @type {module:@jsdoc/core.Env}
      */
     this.env = opts?.env ?? new Env();
   }
@@ -97,4 +103,52 @@ export default class Api {
 
     return this.env.sourceFiles?.slice() ?? [];
   }
+
+  /**
+   * Generates documentation with the template specified in the JSDoc environment, or with
+   * `@jsdoc/template-legacy` if no template is specified.
+   *
+   * The template must export a `publish` function that generates output when called and returns a
+   * `Promise`.
+   *
+   * @param {module:@jsdoc/doclet.DocletStore} docletStore - The doclet store obtained by parsing
+   * the source files.
+   * @returns {Promise<*>} A promise that is fulfilled after the template runs.
+   */
+  async generateDocs(docletStore) {
+    let message;
+    const { log, options } = this.env;
+    let template;
+
+    options.template ??= DEFAULT_TEMPLATE;
+
+    try {
+      template = await import(options.template);
+    } catch (e) {
+      if (options.template === DEFAULT_TEMPLATE) {
+        message =
+          `Unable to load the default template, \`${DEFAULT_TEMPLATE}\`. You can install ` +
+          'the default template, or you can install a different template and configure JSDoc to ' +
+          'use that template.';
+      } else {
+        message = `Unable to load the template \`${options.template}\`: ${e.message ?? e}`;
+      }
+
+      log.fatal(message);
+
+      return Promise.reject(new Error(message));
+    }
+
+    // Templates must export a `publish` function.
+    if (template.publish && typeof template.publish === 'function') {
+      log.info('Generating output files...');
+
+      return template.publish(docletStore, this.env);
+    } else {
+      message = `\`${options.template}\` does not export a \`publish\` function.`;
+      log.fatal(message);
+
+      return Promise.reject(new Error(message));
+    }
+  }
 }
diff --git a/packages/jsdoc-core/test/fixtures/templates/bad-publish-template.js b/packages/jsdoc-core/test/fixtures/templates/bad-publish-template.js
new file mode 100644
index 00000000..23f1b4bc
--- /dev/null
+++ b/packages/jsdoc-core/test/fixtures/templates/bad-publish-template.js
@@ -0,0 +1,17 @@
+/*
+  Copyright 2024 the JSDoc Authors.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      https://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+export const publish = 'foo';
diff --git a/packages/jsdoc-core/test/fixtures/templates/fake-template.js b/packages/jsdoc-core/test/fixtures/templates/fake-template.js
new file mode 100644
index 00000000..7ed3dbca
--- /dev/null
+++ b/packages/jsdoc-core/test/fixtures/templates/fake-template.js
@@ -0,0 +1,22 @@
+/*
+  Copyright 2024 the JSDoc Authors.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      https://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+export function publish(docletStore, env) {
+  env.docletStore = docletStore;
+  env.foo = 'bar';
+
+  return Promise.resolve();
+}
diff --git a/packages/jsdoc-core/test/fixtures/templates/no-publish-template.js b/packages/jsdoc-core/test/fixtures/templates/no-publish-template.js
new file mode 100644
index 00000000..a18d0e20
--- /dev/null
+++ b/packages/jsdoc-core/test/fixtures/templates/no-publish-template.js
@@ -0,0 +1,17 @@
+/*
+  Copyright 2024 the JSDoc Authors.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      https://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+export const foo = 'bar';
diff --git a/packages/jsdoc-core/test/specs/lib/api.js b/packages/jsdoc-core/test/specs/lib/api.js
index fe00eb78..a0894867 100644
--- a/packages/jsdoc-core/test/specs/lib/api.js
+++ b/packages/jsdoc-core/test/specs/lib/api.js
@@ -173,4 +173,100 @@ describe('Api', () => {
       });
     });
   });
+
+  describe('generateDocs', () => {
+    let env;
+    let options;
+
+    beforeEach(() => {
+      env = instance.env;
+      options = env.options;
+      options.template = path.resolve(
+        path.join(__dirname, '../../fixtures/templates/fake-template.js')
+      );
+    });
+
+    it('calls the `publish` function from the specified template', async () => {
+      await instance.generateDocs();
+
+      expect(env.foo).toBe('bar');
+    });
+
+    it('passes the `DocletStore` and `Env` to the template', async () => {
+      const fakeDocletStore = {};
+
+      await instance.generateDocs(fakeDocletStore);
+
+      expect(env.docletStore).toBe(fakeDocletStore);
+    });
+
+    it('uses the legacy template by default', async () => {
+      options.template = null;
+
+      try {
+        await instance.generateDocs();
+
+        // We shouldn't get here.
+        expect(false).toBeTrue();
+      } catch (e) {
+        expect(e.message).toContain('default template');
+        expect(e.message).toContain('@jsdoc/template-legacy');
+      }
+    });
+
+    it('rejects the promise and logs a fatal error if the template cannot be found', async () => {
+      spyOn(env.log, 'fatal');
+      options.template = 'fleeble';
+
+      try {
+        await instance.generateDocs();
+
+        // We shouldn't get here.
+        expect(false).toBeTrue();
+      } catch (e) {
+        expect(e.message).toContain('fleeble');
+      }
+
+      expect(env.log.fatal).toHaveBeenCalled();
+      expect(env.log.fatal.calls.first().args[0]).toContain('fleeble');
+    });
+
+    it('rejects the promise and logs a fatal error if `publish` is undefined', async () => {
+      spyOn(env.log, 'fatal');
+      options.template = path.resolve(
+        path.join(__dirname, '../../fixtures/templates/no-publish-template.js')
+      );
+
+      try {
+        await instance.generateDocs();
+
+        // We shouldn't get here.
+        expect(false).toBeTrue();
+      } catch (e) {
+        expect(e.message).toContain('no-publish-template.js');
+      }
+
+      expect(env.log.fatal).toHaveBeenCalled();
+      expect(env.log.fatal.calls.first().args[0]).toContain('no-publish-template.js');
+    });
+
+    it('rejects the promise and logs a fatal error if `publish` is not a function', async () => {
+      spyOn(env.log, 'fatal');
+      options.template = path.resolve(
+        path.join(__dirname, '../../fixtures/templates/bad-publish-template.js')
+      );
+
+      try {
+        await instance.generateDocs();
+
+        // We shouldn't get here.
+        expect(false).toBeTrue();
+      } catch (e) {
+        expect(e.message).toContain('bad-publish-template.js');
+      }
+
+      expect(env.log.fatal).toHaveBeenCalled();
+      expect(env.log.fatal.calls.first().args[0]).toContain('bad-publish-template.js');
+    });
+  });
 });
diff --git a/packages/jsdoc/cli.js b/packages/jsdoc/cli.js
index aa338ba3..cac2a0c2 100644
--- a/packages/jsdoc/cli.js
+++ b/packages/jsdoc/cli.js
@@ -260,36 +260,7 @@ export default (() => {
     return cli;
   };
 
-  cli.generateDocs = async () => {
-    let message;
-    const { options } = env;
-    let template;
-
-    options.template ??= '@jsdoc/template-legacy';
-
-    try {
-      template = await import(options.template);
-    } catch (e) {
-      log.fatal(`Unable to load template: ${e.message ?? e}`);
-    }
-
-    // templates should export a "publish" function
-    if (template.publish && typeof template.publish === 'function') {
-      let publishPromise;
-
-      log.info('Generating output files...');
-      publishPromise = template.publish(props.docs, env);
-
-      return Promise.resolve(publishPromise);
-    } else {
-      message =
-        `${options.template} does not export a "publish" function. ` +
-        'Global "publish" functions are no longer supported.';
-      log.fatal(message);
-
-      return Promise.reject(new Error(message));
-    }
-  };
+  cli.generateDocs = () => api.generateDocs(props.docs);
 
   return cli;
 })();