diff --git a/templates/zerver/api/arguments.json b/templates/zerver/api/arguments.json
index 29c4e8468d..b3c492c5cf 100644
--- a/templates/zerver/api/arguments.json
+++ b/templates/zerver/api/arguments.json
@@ -1,12 +1,4 @@
 {
-    "get-stream-id.md": [
-        {
-            "argument": "stream",
-            "description": "The name of the stream to retrieve the ID for.",
-            "required": true,
-            "example": "Denmark"
-        }
-    ],
     "render-message.md": [
         {
             "argument": "content",
diff --git a/templates/zerver/api/fixtures.json b/templates/zerver/api/fixtures.json
index a8a54dc252..b4f17796bb 100644
--- a/templates/zerver/api/fixtures.json
+++ b/templates/zerver/api/fixtures.json
@@ -115,11 +115,6 @@
         "short_name": "iago",
         "user_id": 5
     },
-    "get-stream-id": {
-        "msg": "",
-        "result": "success",
-        "stream_id": 15
-    },
     "get-subscribed-streams": {
         "msg": "",
         "result": "success",
@@ -207,11 +202,6 @@
         "msg": "Invalid API key",
         "result": "error"
     },
-    "invalid-stream-error": {
-        "code": "BAD_REQUEST",
-        "msg": "Invalid stream name 'nonexistent'",
-        "result": "error"
-    },
     "missing-request-argument-error": {
         "code": "REQUEST_VARIABLE_MISSING",
         "msg": "Missing 'content' argument",
diff --git a/templates/zerver/api/get-stream-id.md b/templates/zerver/api/get-stream-id.md
index 6a94e35d27..69c0e50add 100644
--- a/templates/zerver/api/get-stream-id.md
+++ b/templates/zerver/api/get-stream-id.md
@@ -24,7 +24,7 @@ curl {{ api_url }}/v1/get_stream_id?stream=Denmark \
 
 <div data-language="python" markdown="1">
 
-{generate_code_example(python)|get-stream-id|example}
+{generate_code_example(python)|/get_stream_id:get|example}
 
 </div>
 
@@ -53,7 +53,7 @@ zulip(config).then((client) => {
 
 **Note**: The following arguments are all URL query parameters.
 
-{generate_api_arguments_table|arguments.json|get-stream-id.md}
+{generate_api_arguments_table|zulip.yaml|/get_stream_id:get}
 
 ## Response
 
@@ -65,8 +65,8 @@ zulip(config).then((client) => {
 
 A typical successful JSON response may look like:
 
-{generate_code_example|get-stream-id|fixture}
+{generate_code_example|/get_stream_id:get|fixture(200)}
 
 An example JSON response for when the supplied stream does not exist:
 
-{generate_code_example|invalid-stream-error|fixture}
+{generate_code_example|/get_stream_id:get|fixture(400)}
diff --git a/zerver/lib/api_test_helpers.py b/zerver/lib/api_test_helpers.py
index 07637afa5b..b580c68ee2 100644
--- a/zerver/lib/api_test_helpers.py
+++ b/zerver/lib/api_test_helpers.py
@@ -188,9 +188,7 @@ def get_stream_id(client):
     result = client.get_stream_id(stream_name)
     # {code_example|end}
 
-    fixture = FIXTURES['get-stream-id']
-    test_against_fixture(result, fixture, check_if_equal=['msg', 'result'],
-                         check_if_exists=['stream_id'])
+    validate_against_openapi_schema(result, '/get_stream_id', 'get', '200')
 
 def get_streams(client):
     # type: (Client) -> None
@@ -491,14 +489,13 @@ def test_invalid_stream_error(client):
     # type: (Client) -> None
     result = client.get_stream_id('nonexistent')
 
-    fixture = FIXTURES['invalid-stream-error']
-    test_against_fixture(result, fixture)
+    validate_against_openapi_schema(result, '/get_stream_id', 'get', '400')
 
 TEST_FUNCTIONS = {
     'render-message': render_message,
     '/messages:post': send_message,
     '/messages/{message_id}:patch': update_message,
-    'get-stream-id': get_stream_id,
+    '/get_stream_id:get': get_stream_id,
     'get-subscribed-streams': list_subscriptions,
     '/streams:get': get_streams,
     'create-user': create_user,
diff --git a/zerver/openapi/zulip.yaml b/zerver/openapi/zulip.yaml
index da76d0049f..25fdb91d0d 100644
--- a/zerver/openapi/zulip.yaml
+++ b/zerver/openapi/zulip.yaml
@@ -24,6 +24,50 @@ servers:
 # Endpoint definitions
 #######################
 paths:
+  /get_stream_id:
+    get:
+      description: Get the unique ID of a given stream.
+      parameters:
+      - name: stream
+        in: query
+        description: The name of the stream to retrieve the ID for.
+        schema:
+           type: string
+        example: Denmark
+        required: true
+      security:
+      - basicAuth: []
+      responses:
+        '200':
+          description: Success
+          content:
+            application/json:
+              schema:
+                allOf:
+                - $ref: '#/components/schemas/JsonSuccess'
+                - properties:
+                    stream_id:
+                      type: integer
+                      description: The ID of the given stream.
+                - example:
+                    {
+                        "msg": "",
+                        "result": "success",
+                        "stream_id": 15
+                    }
+        '400':
+          description: Bad request
+          content:
+            application/json:
+              schema:
+                allOf:
+                - $ref: '#/components/schemas/CodedError'
+                - example:
+                    {
+                        "code": "BAD_REQUEST",
+                        "msg": "Invalid stream name 'nonexistent'",
+                        "result": "error"
+                    }
   /messages:
     post:
       description: Send a message.