diff --git a/README.md b/README.md
index 10fb412..272ae0f 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ A simple library to generate URLs for various Taskcluster resources across our v
 This serves as both a simple shim for projects that use JavaScript but also is the reference implementation for
 how we define these paths.
 
-URLs are defined in the 'Taskcluster URL Format' document.
+URLs are defined in the '[Taskcluster URL Format](https://github.com/taskcluster/taskcluster-lib-urls/tree/master/docs/urls-spec.md)' document.
 
 Changelog
 ---------
@@ -40,6 +40,7 @@ root URL:
 * `apiManifest(rootUrl)` -> `String`
 * `testRootUrl()` -> `String`
 * `withRootUrl(rootUrl)` -> `Class` instance for above methods
+* `normalizeRootUrl(rootUrl)` -> `String` (the "normalized" form of the given rootUrl)
 
 When the `rootUrl` is `https://taskcluster.net`, the generated URLs will be to the Heroku cluster. Otherwise they will follow the
 [spec defined in this project](https://github.com/taskcluster/taskcluster-lib-urls/tree/master/docs/urls-spec.md).
@@ -113,6 +114,7 @@ func ExchangesReferenceSchema(rootURL string, version string) string
 func MetadataMetaschema(rootURL string) string
 func UI(rootURL string, path string) string
 func APIManifest(rootURL string) string
+func NormalizedRootURL(rootURL string) string
 ```
 
 Install with:
@@ -146,6 +148,7 @@ taskcluster_urls.exchange_reference(root_url, 'auth', 'v1')
 taskcluster_urls.ui(root_url, 'foo/bar')
 taskcluster_urls.apiManifest(root_url)
 taskcluster_urls.docs(root_url, 'foo/bar')
+taskcluster_urls.normalized_root_url(root_url)
 
 And for testing,
 ```python
diff --git a/docs/urls-spec.md b/docs/urls-spec.md
index 149bf16..6dbb387 100644
--- a/docs/urls-spec.md
+++ b/docs/urls-spec.md
@@ -13,6 +13,10 @@ Example:
 https://taskcluster.example.com
 ```
 
+Normally, a rootUrl has no trailing `/` characters.
+We suggest that libraries and tools be lenient and accept rootUrls containing a trailing `/`, but produce rootUrls without a trailing `/`.
+The `normalizeRootUrl` function supports this practice.
+
 # URLs
 
 Taskcluster uses URLs with the following pattern:
diff --git a/src/index.js b/src/index.js
index 1c6a3a1..deec34f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -290,4 +290,11 @@ module.exports = {
   testRootUrl() {
     return 'https://tc-tests.example.com';
   },
+
+  /**
+   * Return the normal form of this rootUrl
+   */
+  normalizeRootUrl(rootUrl) {
+    return cleanRoot(rootUrl);
+  },
 };
diff --git a/taskcluster_urls/__init__.py b/taskcluster_urls/__init__.py
index 687882d..cbd04b0 100644
--- a/taskcluster_urls/__init__.py
+++ b/taskcluster_urls/__init__.py
@@ -88,3 +88,7 @@ def test_root_url():
     """Returns a standardized "testing" rootUrl that does not resolve but
     is easily recognizable in test failures."""
     return 'https://tc-tests.example.com'
+
+def normalize_root_url(root_url):
+    """Return the normal form of the given rootUrl"""
+    return root_url.rstrip('/')
diff --git a/tcurls.go b/tcurls.go
index 53453f9..850181e 100644
--- a/tcurls.go
+++ b/tcurls.go
@@ -106,3 +106,8 @@ func APIManifest(rootURL string) string {
 		return fmt.Sprintf("%s/references/manifest.json", r)
 	}
 }
+
+// NormalizeRootURL returns the normal form of the given rootURL.
+func NormalizeRootURL(rootURL string) string {
+	return strings.TrimRight(rootURL, "/")
+}
diff --git a/tcurls_test.go b/tcurls_test.go
index 18c9c52..ef95337 100644
--- a/tcurls_test.go
+++ b/tcurls_test.go
@@ -19,6 +19,20 @@ type TestsSpecification struct {
 	Tests    []TestCase          `yaml:"tests"`
 }
 
+func getTests() (*TestsSpecification, error) {
+	data, err := ioutil.ReadFile("tests.yml")
+	if err != nil {
+		return nil, err
+	}
+	var spec TestsSpecification
+	err = yaml.Unmarshal([]byte(data), &spec)
+	if err != nil {
+		return nil, err
+	}
+
+	return &spec, nil
+}
+
 func testFunc(t *testing.T, function string, expectedURL string, root string, args ...string) {
 	var actualURL string
 	switch function {
@@ -56,16 +70,10 @@ func testFunc(t *testing.T, function string, expectedURL string, root string, ar
 }
 
 func TestURLs(t *testing.T) {
-	data, err := ioutil.ReadFile("tests.yml")
+	spec, err := getTests()
 	if err != nil {
 		t.Error(err)
 	}
-	var spec TestsSpecification
-	err = yaml.Unmarshal([]byte(data), &spec)
-	if err != nil {
-		t.Error(err)
-	}
-
 	for _, test := range spec.Tests {
 		for _, argSet := range test.ArgSets {
 			for cluster, rootURLs := range spec.RootURLs {
@@ -77,6 +85,22 @@ func TestURLs(t *testing.T) {
 	}
 }
 
+func TestNormalize(t *testing.T) {
+	spec, err := getTests()
+	if err != nil {
+		t.Error(err)
+	}
+
+	expected := spec.RootURLs["new"][0]
+	for _, rootURL := range spec.RootURLs["new"] {
+		actual := NormalizeRootURL(rootURL)
+		if expected != actual {
+			t.Errorf("%v NormalizeRootURL(%v) = `%v` but should be `%v`", redCross(), rootURL, actual, expected)
+		}
+		t.Logf("%v NormalizeRootURL(%v) = `%v`", greenTick(), rootURL, actual)
+	}
+}
+
 // quotedList returns a backtick-quoted list of the arguments passed in
 func quotedList(url string, args []string) string {
 	all := append([]string{url}, args...)
diff --git a/test/basic_test.js b/test/basic_test.js
index e65f284..c2d6aa8 100644
--- a/test/basic_test.js
+++ b/test/basic_test.js
@@ -5,14 +5,13 @@ const yaml = require('js-yaml');
 const libUrls = require('../');
 
 const SPEC_FILE = path.join(__dirname, '../tests.yml');
+const TESTS = yaml.safeLoad(fs.readFileSync(SPEC_FILE, {encoding: 'utf8'}));
 
 suite('basic test', function() {
-
-  var doc = yaml.safeLoad(fs.readFileSync(SPEC_FILE, {encoding: 'utf8'}));
-  for (let t of doc['tests']) {
+  for (let t of TESTS['tests']) {
     for (let argSet of t['argSets']) {
-      for (let cluster of Object.keys(doc['rootURLs'])) {
-        for (let rootURL of doc['rootURLs'][cluster]) {
+      for (let cluster of Object.keys(TESTS['rootURLs'])) {
+        for (let rootURL of TESTS['rootURLs'][cluster]) {
           test(`${t['function']} - ${argSet}`, function() {
             assert.equal(t['expected'][cluster], libUrls.withRootUrl(rootURL)[t['function']](...argSet));
             assert.equal(t['expected'][cluster], libUrls[t['function']](rootURL, ...argSet));  
@@ -22,3 +21,12 @@ suite('basic test', function() {
     }
   }
 });
+
+suite('normalization', function() {
+  const correct = TESTS.rootURLs['new'][0];
+  for (let rootUrl of TESTS.rootURLs['new']) {
+    test(`normalize ${rootUrl}`, function() {
+      assert.equal(libUrls.normalizeRootUrl(rootUrl), correct);
+    });
+  }
+});
diff --git a/test/normalize_test.py b/test/normalize_test.py
new file mode 100644
index 0000000..35ba863
--- /dev/null
+++ b/test/normalize_test.py
@@ -0,0 +1,24 @@
+import os
+import yaml
+import taskcluster_urls as tcurls
+
+
+SPEC_FILE = os.path.join(os.path.dirname(__file__), '..', 'tests.yml')
+
+
+def pytest_generate_tests(metafunc):
+    with open(SPEC_FILE) as testsFile:
+        spec = yaml.load(testsFile)
+        root_urls = spec['rootURLs']['new']
+        expected_url = root_urls[0]
+        metafunc.parametrize(
+            ['expected_url', 'root_url'],
+            [
+                (expected_url, root_url)
+                for root_url in root_urls
+            ]
+        )
+
+
+def test_normalize(expected_url, root_url):
+    assert tcurls.normalize_root_url(root_url) == expected_url