diff --git a/README.md b/README.md
index 1b9d53c..fd67086 100644
--- a/README.md
+++ b/README.md
@@ -9,4 +9,6 @@ server readiness, health, errors, and the transport-neutral realtime event
 envelope so the client and server can be developed and tested together before
 Twitch integration. It also defines the first administrator authentication
 request and response envelopes; bearer values in fixtures are synthetic only.
+Twitch OAuth link and completion response envelopes are also versioned here;
+fixtures contain no real credentials or tokens.
 
diff --git a/contracts/v1/twitch-oauth-link-response.json b/contracts/v1/twitch-oauth-link-response.json
new file mode 100644
index 0000000..6e621e5
--- /dev/null
+++ b/contracts/v1/twitch-oauth-link-response.json
@@ -0,0 +1,23 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://trixie.reaperofveriod.nl/contracts/v1/twitch-oauth-link-response.json",
+  "title": "Twitch OAuth authorization link response",
+  "type": "object",
+  "additionalProperties": false,
+  "required": ["identity", "scopes", "authorization_url", "expires_in_seconds"],
+  "properties": {
+    "identity": { "enum": ["streamer", "bot", "moderator"] },
+    "scopes": {
+      "type": "array",
+      "items": { "type": "string", "minLength": 1 },
+      "minItems": 1,
+      "uniqueItems": true
+    },
+    "authorization_url": {
+      "type": "string",
+      "format": "uri",
+      "pattern": "^https://id\\.twitch\\.tv/oauth2/authorize\\?"
+    },
+    "expires_in_seconds": { "type": "integer", "const": 600 }
+  }
+}
diff --git a/contracts/v1/twitch-oauth-result.json b/contracts/v1/twitch-oauth-result.json
new file mode 100644
index 0000000..21ea0d2
--- /dev/null
+++ b/contracts/v1/twitch-oauth-result.json
@@ -0,0 +1,13 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://trixie.reaperofveriod.nl/contracts/v1/twitch-oauth-result.json",
+  "title": "Twitch OAuth completion response",
+  "type": "object",
+  "additionalProperties": false,
+  "required": ["identity", "twitch_user_id", "display_name"],
+  "properties": {
+    "identity": { "enum": ["streamer", "bot", "moderator"] },
+    "twitch_user_id": { "type": "string", "minLength": 1 },
+    "display_name": { "type": "string", "minLength": 1 }
+  }
+}
diff --git a/fixtures/v1/twitch-oauth-link.response.json b/fixtures/v1/twitch-oauth-link.response.json
new file mode 100644
index 0000000..13205f5
--- /dev/null
+++ b/fixtures/v1/twitch-oauth-link.response.json
@@ -0,0 +1,6 @@
+{
+  "identity": "bot",
+  "scopes": ["channel:bot", "user:read:chat", "user:write:chat"],
+  "authorization_url": "https://id.twitch.tv/oauth2/authorize?client_id=public-example-client&redirect_uri=http%3A%2F%2Flocalhost%3A8787%2Fapi%2Fv1%2Ftwitch%2Foauth%2Fcallback&response_type=code&scope=channel%3Abot+user%3Aread%3Achat+user%3Awrite%3Achat&state=synthetic-state",
+  "expires_in_seconds": 600
+}
diff --git a/fixtures/v1/twitch-oauth-result.response.json b/fixtures/v1/twitch-oauth-result.response.json
new file mode 100644
index 0000000..a3f67e7
--- /dev/null
+++ b/fixtures/v1/twitch-oauth-result.response.json
@@ -0,0 +1,5 @@
+{
+  "identity": "streamer",
+  "twitch_user_id": "synthetic-twitch-user-id",
+  "display_name": "SyntheticStreamer"
+}