diff --git a/CHANGELOG.md b/CHANGELOG.md
index de85088..5ec1768 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,15 @@ and `latest` stayed on the non-module 1.0.8.
   unversioned CDN URLs get the ES module build. `latest` was moved from 1.0.8 to 1.1.11 on 2026-11-12
   (`npm dist-tag add`). `module` stays on 1.1.11. A page that loads the non-module
   1.0.8 with an unversioned script tag must pin it: https://unpkg.com/convertapi-js@1.0.8/lib/convertapi.js
+- `ConvertApi.auth()` also takes the host as a URL: a leading `https://` or `http://` and trailing slashes
+  are removed, so `ConvertApi.auth('api-token', 'https://eu-v2.convertapi.com/')` sends requests to
+  `https://eu-v2.convertapi.com/convert/...`. Before, that form failed with "fetch failed", because the
+  library requested `https://https://eu-v2.convertapi.com//convert/...`. The README showed it from
+  2023-07-04 until https://github.com/ConvertAPI/convertapi-library-js/pull/34. Requests always use https.
+- The type declarations (`dist/*.d.ts`) keep their JSDoc comments, so editors show them; the build used to
+  remove them. The `auth()` comment describes the API token and the host name instead of the retired
+  `secret` and `apiKey`/`token` object, and `Result.duration` is described as the conversion cost
+  (`ConversionCost`) rather than a duration in seconds.
 
 ## 1.1.11 - 2026-10-20
 
diff --git a/package.json b/package.json
index 4f7fa31..cc13143 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,7 @@
     "dist"
   ],
   "scripts": {
-    "build": "tsc",
+    "build": "tsc && tsc --emitDeclarationOnly --removeComments false",
     "test": "npm run build && node --test test/*.test.js",
     "prepublishOnly": "echo 'convertapi-js is published by a GitHub Release, see RELEASING.md' && exit 1"
   },
diff --git a/src/convertapi.ts b/src/convertapi.ts
index b7c78c5..9117d3e 100644
--- a/src/convertapi.ts
+++ b/src/convertapi.ts
@@ -5,20 +5,28 @@ import Result, {IResultErrorDto} from "./result.js";
 export default class ConvertApi {
 
     /**
-     * Returns ConvertApi object ready to use for conversions
+     * Returns a ConvertApi object ready to use for conversions.
      *
-     * @param credentials - Your ConvertAPI credentials. Should be an `Object` with the `secret` or `apiKey` and `token` properties.
-     * @param host - ConvertApi server domain name
+     * @param credentials - Your API token (https://www.convertapi.com/a/authentication), sent in the `Authorization: Bearer` header.
+     * @param host - API host name, without `https://` or a trailing slash: `v2.convertapi.com` (the default) or a regional host such as `eu-v2.convertapi.com` (https://www.convertapi.com/docs/servers-location). A leading `https://` or `http://` and trailing slashes are removed; requests always use https.
      * @returns - New ConvertApi object
      */
     static auth(credentials: string, host?: string): ConvertApi {
         return new ConvertApi(credentials, host)
     }
 
+    /** API host name that requests go to, such as `v2.convertapi.com`, without `https://` or a trailing slash. */
+    public readonly host: string
+
     constructor(
         public readonly authCredentials: string,
-        public readonly host: string='v2.convertapi.com'
-    ) {}
+        host: string = 'v2.convertapi.com'
+    ) {
+        // Requests go to https://{host}/..., so a host given as a URL, such as 'https://eu-v2.convertapi.com/'
+        // (in the README until https://github.com/ConvertAPI/convertapi-library-js/pull/34), loses its scheme
+        // and trailing slashes instead of breaking every request.
+        this.host = host.replace(/^https?:\/\//i, '').replace(/\/+$/, '')
+    }
 
     /**
      * Returns initialized and ready to use new conversion parameters object.
diff --git a/src/result.ts b/src/result.ts
index 7cb341d..afb63e1 100644
--- a/src/result.ts
+++ b/src/result.ts
@@ -30,7 +30,7 @@ export default class Result {
     ) {}
 
     /**
-     * Returns conversion duration seconds
+     * Returns the conversion cost (`ConversionCost`), the amount deducted from your balance for this conversion.
      */
     public get duration(): number {
         return this.dto.ConversionCost
diff --git a/test/convertapi.test.js b/test/convertapi.test.js
index 533821c..1a402ce 100644
--- a/test/convertapi.test.js
+++ b/test/convertapi.test.js
@@ -1,5 +1,6 @@
 import { test } from 'node:test'
 import assert from 'node:assert/strict'
+import { readFile } from 'node:fs/promises'
 import { stubFetch } from './setup.js'
 import ConvertApi from '../dist/convertapi.js'
 import { FileValue } from '../dist/file-param.js'
@@ -16,6 +17,44 @@ test('auth() keeps the token and defaults to v2.convertapi.com', () => {
     assert.equal(ConvertApi.auth('token-1', 'example.test').host, 'example.test')
 })
 
+test('auth() takes the host as a URL too: https://, http:// and trailing slashes are removed', () => {
+    const cases = [
+        ['https://eu-v2.convertapi.com/', 'eu-v2.convertapi.com'],
+        ['https://eu-v2.convertapi.com', 'eu-v2.convertapi.com'],
+        ['HTTPS://eu-v2.convertapi.com/', 'eu-v2.convertapi.com'],
+        ['http://eu-v2.convertapi.com/', 'eu-v2.convertapi.com'],
+        ['eu-v2.convertapi.com//', 'eu-v2.convertapi.com'],
+        ['eu-v2.convertapi.com', 'eu-v2.convertapi.com'],
+        ['http://localhost:8080/', 'localhost:8080']
+    ]
+    for (const [host, expected] of cases) {
+        assert.equal(ConvertApi.auth('token-1', host).host, expected, host)
+    }
+    assert.equal(new ConvertApi('token-1', 'https://example.test/').host, 'example.test')
+})
+
+test('a host given as a URL is used for uploads and conversions', async t => {
+    const calls = stubFetch(t, { body: { FileId: 'up-1' } }, { body: { FileId: 'up-2' } }, { body: result })
+    // The form the README showed until https://github.com/ConvertAPI/convertapi-library-js/pull/34
+    const api = ConvertApi.auth('token-1', 'https://example.test/')
+    const params = api.createParams()
+    params.add('File', new File(['%PDF'], 'a.pdf'))
+    params.add('OverlayFile', new URL('https://cdn.example.test/overlay.pdf'))
+
+    await api.convert('pdf', 'pdf-watermark', params)
+
+    assert.deepEqual(calls.map(c => c.url), [
+        'https://example.test/upload?filename=a.pdf',
+        'https://example.test/upload?url=https%3A%2F%2Fcdn.example.test%2Foverlay.pdf',
+        'https://example.test/convert/pdf/to/pdf-watermark?storefile=true'
+    ])
+})
+
+test('the type declarations keep the JSDoc that editors show', async () => {
+    const dts = await readFile(new URL('../dist/convertapi.d.ts', import.meta.url), 'utf8')
+    assert.match(dts, /@param host - API host name, without `https:\/\/`/)
+})
+
 test('convert() posts the parameters with a Bearer token and returns the result', async t => {
     const calls = stubFetch(t, { body: result })
     const api = ConvertApi.auth('token-1', 'example.test')
diff --git a/tsconfig.json b/tsconfig.json
index 5219eb6..cc90518 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -14,6 +14,8 @@
     "noUnusedLocals": true,
     "strictNullChecks": true,
 
+    // The JavaScript ships without comments. `npm run build` then emits the declarations a second time
+    // with --removeComments false, so dist/*.d.ts keep the JSDoc that editors show.
     "removeComments": true,
     "sourceMap": true,
     "declaration": true,