diff --git a/data/api/client-server/definitions/request_email_validation.yaml b/data/api/client-server/definitions/request_email_validation.yaml
index d52ea18e..aa47e658 100644
--- a/data/api/client-server/definitions/request_email_validation.yaml
+++ b/data/api/client-server/definitions/request_email_validation.yaml
@@ -18,6 +18,7 @@ allOf:
   properties:
     id_server:
       type: string
+      format: mx-server-name
       description: |-
         The hostname of the identity server to communicate with. May optionally
         include a port. This parameter is ignored when the homeserver handles
diff --git a/data/api/client-server/definitions/request_msisdn_validation.yaml b/data/api/client-server/definitions/request_msisdn_validation.yaml
index fba3a615..8d5d7385 100644
--- a/data/api/client-server/definitions/request_msisdn_validation.yaml
+++ b/data/api/client-server/definitions/request_msisdn_validation.yaml
@@ -18,6 +18,7 @@ allOf:
   properties:
     id_server:
       type: string
+      format: mx-server-name
       description: |-
         The hostname of the identity server to communicate with. May optionally
         include a port. This parameter is ignored when the homeserver handles
diff --git a/data/api/client-server/registration.yaml b/data/api/client-server/registration.yaml
index 1dd314b8..a2d04305 100644
--- a/data/api/client-server/registration.yaml
+++ b/data/api/client-server/registration.yaml
@@ -135,6 +135,8 @@ paths:
                 properties:
                   user_id:
                     type: string
+                    format: mx-user-id
+                    pattern: "^@"
                     description: |-
                       The fully-qualified Matrix user ID (MXID) that has been registered.
 
@@ -169,6 +171,7 @@ paths:
                     x-addedInMatrixVersion: "1.3"
                   home_server:
                     type: string
+                    format: mx-server-name
                     deprecated: true
                     description: |-
                       The server_name of the homeserver on which the account has
@@ -611,6 +614,7 @@ paths:
                     - $ref: definitions/auth_data.yaml
                 id_server:
                   type: string
+                  format: mx-server-name
                   description: |-
                     The identity server to unbind all of the user's 3PIDs from.
                     If not provided, the homeserver MUST use the `id_server`
diff --git a/data/api/identity/definitions/request_email_validation.yaml b/data/api/identity/definitions/request_email_validation.yaml
index a447c871..f165c6ac 100644
--- a/data/api/identity/definitions/request_email_validation.yaml
+++ b/data/api/identity/definitions/request_email_validation.yaml
@@ -23,6 +23,7 @@ properties:
     example: "monkeys_are_GREAT"
   email:
     type: string
+    format: email
     description: The email address to validate.
     example: "alice@example.org"
   send_attempt:
@@ -39,6 +40,7 @@ properties:
     example: 1
   next_link:
     type: string
+    format: uri
     description: |-
       Optional. When the validation is completed, the identity server will
       redirect the user to this URL. This option is ignored when submitting
diff --git a/data/api/identity/definitions/request_msisdn_validation.yaml b/data/api/identity/definitions/request_msisdn_validation.yaml
index 28544580..5900e447 100644
--- a/data/api/identity/definitions/request_msisdn_validation.yaml
+++ b/data/api/identity/definitions/request_msisdn_validation.yaml
@@ -44,6 +44,7 @@ properties:
     example: 1
   next_link:
     type: string
+    format: uri
     description: |-
       Optional. When the validation is completed, the identity server will
       redirect the user to this URL. This option is ignored when submitting