diff --git a/README.md b/README.md
index 809de75..e46d88a 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ npm install @cityssm/faster-url-builder
 import { FasterUrlBuilder } from '@cityssm/faster-url-builder'
 
 console.log(new FasterUrlBuilder('test-tenant').loginUrl)
-// => https://test-tenant.fasterwebcloud.com/FASTER
+// => https://test-tenant.fasterwebcloud.com/FASTER/Login
 ```
 
 ## Included URLs
@@ -40,8 +40,8 @@ console.log(new FasterUrlBuilder('test-tenant').loginUrl)
 
 ## Related Projects
 
-[FASTER Web Report Exporter](https://github.com/cityssm/node-faster-report-exporter)<br />
+[**FASTER Web Report Exporter**](https://github.com/cityssm/node-faster-report-exporter)<br />
 On demand exports of selected reports from the FASTER Web Fleet Management System.
 
-[FASTER Web Helper](https://github.com/cityssm/faster-web-helper)<br />
+[**FASTER Web Helper**](https://github.com/cityssm/faster-web-helper)<br />
 A service to support integrations with the FASTER Web fleet management system.
diff --git a/eslint.config.d.ts b/eslint.config.d.ts
index 29528c9..a1905cc 100644
--- a/eslint.config.d.ts
+++ b/eslint.config.d.ts
@@ -1 +1,3 @@
-export { default } from 'eslint-config-cityssm';
+import { type Config } from 'eslint-config-cityssm';
+declare const config: Config;
+export default config;
diff --git a/eslint.config.js b/eslint.config.js
index 29528c9..fa3adae 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -1 +1,14 @@
-export { default } from 'eslint-config-cityssm';
+import eslintConfigCityssm, { cspellWords, tseslint } from 'eslint-config-cityssm';
+const config = tseslint.config(...eslintConfigCityssm, {
+    rules: {
+        '@cspell/spellchecker': [
+            'warn',
+            {
+                cspell: {
+                    words: [...cspellWords, 'fasterwebcloud']
+                }
+            }
+        ]
+    }
+});
+export default config;
diff --git a/eslint.config.ts b/eslint.config.ts
index a6257c1..24890e2 100644
--- a/eslint.config.ts
+++ b/eslint.config.ts
@@ -1 +1,20 @@
-export { default } from 'eslint-config-cityssm'
+import eslintConfigCityssm, {
+  type Config,
+  cspellWords,
+  tseslint
+} from 'eslint-config-cityssm'
+
+const config = tseslint.config(...eslintConfigCityssm, {
+  rules: {
+    '@cspell/spellchecker': [
+      'warn',
+      {
+        cspell: {
+          words: [...cspellWords, 'fasterwebcloud']
+        }
+      }
+    ]
+  }
+}) as Config
+
+export default config
diff --git a/index.d.ts b/index.d.ts
index 03583e8..d515f65 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,4 +1,10 @@
-type FasterBaseUrl = `https://${string}.fasterwebcloud.com/FASTER`;
+export type FasterBaseUrl = `https://${string}.fasterwebcloud.com/FASTER`;
+/**
+ * Tests if a base URL is valid.
+ * @param fasterBaseUrl - A possible FASTER Web base URL.
+ * @returns `true` if the base URL is valid.
+ */
+export declare function isValidBaseUrl(fasterBaseUrl: string): fasterBaseUrl is FasterBaseUrl;
 export declare class FasterUrlBuilder {
     #private;
     /** Base URL */
@@ -9,9 +15,10 @@ export declare class FasterUrlBuilder {
     readonly reportViewerUrl: `${FasterBaseUrl}/Domains/Reports/ReportViewer.aspx`;
     /**
      * Initializes the FasterUrlBuilder
-     * @param fasterTenant - The subdomain of the FASTER Web URL before ".fasterwebcloud.com"
+     * @param fasterTenantOrBaseUrl - The subdomain of the FASTER Web URL before ".fasterwebcloud.com"
+     *                                or the full domain and path including "/FASTER"
      */
-    constructor(fasterTenant: string);
+    constructor(fasterTenantOrBaseUrl: string);
     /**
      * Builds a URL for the inventory search.
      * @param searchString - Item number search string
diff --git a/index.js b/index.js
index 97c855f..8b813f7 100644
--- a/index.js
+++ b/index.js
@@ -1,23 +1,39 @@
+/**
+ * Tests if a base URL is valid.
+ * @param fasterBaseUrl - A possible FASTER Web base URL.
+ * @returns `true` if the base URL is valid.
+ */
+export function isValidBaseUrl(fasterBaseUrl) {
+    return (fasterBaseUrl.startsWith('https://') && fasterBaseUrl.endsWith('/FASTER'));
+}
 export class FasterUrlBuilder {
     /** Base URL */
     baseUrl;
     /** Login URL */
     loginUrl;
     #inventorySearchUrl;
+    // eslint-disable-next-line no-secrets/no-secrets
     #workOrderSearchUrl;
     #workOrderUrl;
     /** Report Viewer URL - Parameters required */
     reportViewerUrl;
     /**
      * Initializes the FasterUrlBuilder
-     * @param fasterTenant - The subdomain of the FASTER Web URL before ".fasterwebcloud.com"
+     * @param fasterTenantOrBaseUrl - The subdomain of the FASTER Web URL before ".fasterwebcloud.com"
+     *                                or the full domain and path including "/FASTER"
      */
-    constructor(fasterTenant) {
-        this.baseUrl = `https://${fasterTenant}.fasterwebcloud.com/FASTER`;
+    constructor(fasterTenantOrBaseUrl) {
+        this.baseUrl = fasterTenantOrBaseUrl.startsWith('https')
+            ? fasterTenantOrBaseUrl
+            : `https://${fasterTenantOrBaseUrl}.fasterwebcloud.com/FASTER`;
+        if (!isValidBaseUrl(this.baseUrl)) {
+            throw new Error(`Invalid base URL: ${this.baseUrl}`);
+        }
         this.loginUrl = `${this.baseUrl}/Login`;
         /* Inventory */
         this.#inventorySearchUrl = `${this.baseUrl}/Domains/Parts/Search/Default.aspx?xact=False&type=False&str=`;
         /* Maintenance */
+        // eslint-disable-next-line no-secrets/no-secrets
         this.#workOrderSearchUrl = `${this.baseUrl}/Domains/Maintenance/WorkOrder/Search/Default.aspx?xact=False&type=False&str=`;
         this.#workOrderUrl = `${this.baseUrl}/Domains/Maintenance/WorkOrder/WorkOrderMaster.aspx?workOrderID=`;
         /* Reports */
diff --git a/index.ts b/index.ts
index c0c33e0..bb8f220 100644
--- a/index.ts
+++ b/index.ts
@@ -1,4 +1,17 @@
-type FasterBaseUrl = `https://${string}.fasterwebcloud.com/FASTER`
+export type FasterBaseUrl = `https://${string}.fasterwebcloud.com/FASTER`
+
+/**
+ * Tests if a base URL is valid.
+ * @param fasterBaseUrl - A possible FASTER Web base URL.
+ * @returns `true` if the base URL is valid.
+ */
+export function isValidBaseUrl(
+  fasterBaseUrl: string
+): fasterBaseUrl is FasterBaseUrl {
+  return (
+    fasterBaseUrl.startsWith('https://') && fasterBaseUrl.endsWith('/FASTER')
+  )
+}
 
 export class FasterUrlBuilder {
   /** Base URL */
@@ -9,6 +22,7 @@ export class FasterUrlBuilder {
 
   readonly #inventorySearchUrl: `${FasterBaseUrl}/Domains/Parts/Search/Default.aspx?xact=False&type=False&str=`
 
+  // eslint-disable-next-line no-secrets/no-secrets
   readonly #workOrderSearchUrl: `${FasterBaseUrl}/Domains/Maintenance/WorkOrder/Search/Default.aspx?xact=False&type=False&str=`
   readonly #workOrderUrl: `${FasterBaseUrl}/Domains/Maintenance/WorkOrder/WorkOrderMaster.aspx?workOrderID=`
 
@@ -17,16 +31,25 @@ export class FasterUrlBuilder {
 
   /**
    * Initializes the FasterUrlBuilder
-   * @param fasterTenant - The subdomain of the FASTER Web URL before ".fasterwebcloud.com"
+   * @param fasterTenantOrBaseUrl - The subdomain of the FASTER Web URL before ".fasterwebcloud.com"
+   *                                or the full domain and path including "/FASTER"
    */
-  constructor(fasterTenant: string) {
-    this.baseUrl = `https://${fasterTenant}.fasterwebcloud.com/FASTER`
+  constructor(fasterTenantOrBaseUrl: string) {
+    this.baseUrl = fasterTenantOrBaseUrl.startsWith('https')
+      ? (fasterTenantOrBaseUrl as FasterBaseUrl)
+      : `https://${fasterTenantOrBaseUrl}.fasterwebcloud.com/FASTER`
+
+    if (!isValidBaseUrl(this.baseUrl)) {
+      throw new Error(`Invalid base URL: ${this.baseUrl as string}`)
+    }
+
     this.loginUrl = `${this.baseUrl}/Login`
 
     /* Inventory */
     this.#inventorySearchUrl = `${this.baseUrl}/Domains/Parts/Search/Default.aspx?xact=False&type=False&str=`
 
     /* Maintenance */
+    // eslint-disable-next-line no-secrets/no-secrets
     this.#workOrderSearchUrl = `${this.baseUrl}/Domains/Maintenance/WorkOrder/Search/Default.aspx?xact=False&type=False&str=`
     this.#workOrderUrl = `${this.baseUrl}/Domains/Maintenance/WorkOrder/WorkOrderMaster.aspx?workOrderID=`
 
diff --git a/package-lock.json b/package-lock.json
index f76c543..43c3246 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,15 +1,15 @@
 {
   "name": "@cityssm/faster-url-builder",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@cityssm/faster-url-builder",
-      "version": "0.1.0",
+      "version": "0.2.0",
       "license": "MIT",
       "devDependencies": {
-        "@types/node": "^22.9.0",
+        "@types/node": "^22.9.1",
         "eslint-config-cityssm": "^15.2.0",
         "prettier-config-cityssm": "^1.0.0"
       }
@@ -3092,9 +3092,9 @@
       "license": "MIT"
     },
     "node_modules/@types/node": {
-      "version": "22.9.0",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.9.0.tgz",
-      "integrity": "sha512-vuyHg81vvWA1Z1ELfvLko2c8f34gyA0zaic0+Rllc5lbCnbSyuvb2Oxpm6TAUAC/2xZN3QGqxBNggD1nNR2AfQ==",
+      "version": "22.9.1",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.9.1.tgz",
+      "integrity": "sha512-p8Yy/8sw1caA8CdRIQBG5tiLHmxtQKObCijiAa9Ez+d4+PRffM4054xbju0msf+cvhJpnFEeNjxmVT/0ipktrg==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
diff --git a/package.json b/package.json
index f8ea9e8..22b479d 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@cityssm/faster-url-builder",
   "type": "module",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Builds URLs for the FASTER Web Fleet Management System",
   "exports": "./index.js",
   "scripts": {
@@ -22,7 +22,7 @@
   },
   "homepage": "https://github.com/cityssm/node-faster-url-builder#readme",
   "devDependencies": {
-    "@types/node": "^22.9.0",
+    "@types/node": "^22.9.1",
     "eslint-config-cityssm": "^15.2.0",
     "prettier-config-cityssm": "^1.0.0"
   }
diff --git a/test/test.js b/test/test.js
index 9f97bd6..1d67b5e 100644
--- a/test/test.js
+++ b/test/test.js
@@ -1,10 +1,15 @@
 import assert from 'node:assert';
 import { describe, it } from 'node:test';
-import { FasterUrlBuilder } from '../index.js';
+import { FasterUrlBuilder, isValidBaseUrl } from '../index.js';
 await describe('faster-url-builder', async () => {
     const tenant = 'faster-tenant';
     const fasterUrlBuilder = new FasterUrlBuilder(tenant);
-    await it('Constructs a proper base URL', () => {
+    await it('Initializes with a full base URL', () => {
+        const testBaseUrl = 'https://test.example.com/FASTER';
+        const fasterUrlBuilderFromUrl = new FasterUrlBuilder(testBaseUrl);
+        assert.strictEqual(fasterUrlBuilderFromUrl.baseUrl, testBaseUrl);
+    });
+    await it('Constructs a proper base URL from a tenant', () => {
         assert(fasterUrlBuilder.baseUrl.includes(tenant));
     });
     await it('Constructs a proper login URL', () => {
@@ -32,3 +37,22 @@ await describe('faster-url-builder', async () => {
         assert(workOrderUrl.endsWith(workOrderNumber.toString()));
     });
 });
+await describe('faster-url-builder/errors', async () => {
+    await it('Rejects invalid base URLs', () => {
+        // http link
+        assert.strictEqual(isValidBaseUrl('http://test.example.com/FASTER'), false);
+        // missing "/FASTER"
+        assert.strictEqual(isValidBaseUrl('https://test.example.com'), false);
+        let declaredSuccessfully = false;
+        // eslint-disable-next-line @typescript-eslint/init-declarations
+        let builder;
+        try {
+            builder = new FasterUrlBuilder('https://test.example.com/FASTE');
+            declaredSuccessfully = true;
+        }
+        catch { }
+        if (declaredSuccessfully) {
+            assert.fail(`URL builder declared successfully with invalid URL: ${builder.baseUrl}`);
+        }
+    });
+});
diff --git a/test/test.ts b/test/test.ts
index bd6b7de..15371bf 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -1,13 +1,19 @@
 import assert from 'node:assert'
 import { describe, it } from 'node:test'
 
-import { FasterUrlBuilder } from '../index.js'
+import { FasterUrlBuilder, isValidBaseUrl } from '../index.js'
 
 await describe('faster-url-builder', async () => {
   const tenant = 'faster-tenant'
   const fasterUrlBuilder = new FasterUrlBuilder(tenant)
 
-  await it('Constructs a proper base URL', () => {
+  await it('Initializes with a full base URL', () => {
+    const testBaseUrl = 'https://test.example.com/FASTER'
+    const fasterUrlBuilderFromUrl = new FasterUrlBuilder(testBaseUrl)
+    assert.strictEqual(fasterUrlBuilderFromUrl.baseUrl, testBaseUrl)
+  })
+
+  await it('Constructs a proper base URL from a tenant', () => {
     assert(fasterUrlBuilder.baseUrl.includes(tenant))
   })
 
@@ -51,3 +57,28 @@ await describe('faster-url-builder', async () => {
     assert(workOrderUrl.endsWith(workOrderNumber.toString()))
   })
 })
+
+await describe('faster-url-builder/errors', async () => {
+  await it('Rejects invalid base URLs', () => {
+    // http link
+    assert.strictEqual(isValidBaseUrl('http://test.example.com/FASTER'), false)
+
+    // missing "/FASTER"
+    assert.strictEqual(isValidBaseUrl('https://test.example.com'), false)
+
+    let declaredSuccessfully = false
+
+    // eslint-disable-next-line @typescript-eslint/init-declarations
+    let builder: FasterUrlBuilder | undefined
+
+    try {
+      builder = new FasterUrlBuilder('https://test.example.com/FASTE')
+      declaredSuccessfully = true
+    } catch {}
+    if (declaredSuccessfully) {
+      assert.fail(
+        `URL builder declared successfully with invalid URL: ${(builder as FasterUrlBuilder).baseUrl}`
+      )
+    }
+  })
+})