diff --git a/src/models.py b/src/models.py
new file mode 100644
index 0000000..cc25303
--- /dev/null
+++ b/src/models.py
@@ -0,0 +1,24 @@
+"""Pydantic models for API events."""
+from __future__ import annotations
+
+from typing import Literal, Union
+
+from pydantic import BaseModel, Field, Annotated
+
+class HttpOkEvent(BaseModel):
+    """Successful HTTP event with status 200."""
+    kind: Literal["ok"] = Field("ok", description="Event kind: ok")
+    status: Literal[200] = Field(200, description="HTTP status code")
+    path: str = Field(..., description="Request path")
+    duration_ms: int = Field(..., description="Duration in milliseconds")
+
+class HttpErrorEvent(BaseModel):
+    """Failed HTTP event with 4xx or 5xx status."""
+    kind: Literal["error"] = Field("error", description="Event kind: error")
+    status: int = Field(..., description="HTTP status code (4xx/5xx)")
+    path: str = Field(..., description="Request path")
+    error_message: str = Field(..., description="Error message")
+
+ApiEvent = Annotated[Union[HttpOkEvent, HttpErrorEvent], Field(discriminator="kind")]
+
+__all__ = ["HttpOkEvent", "HttpErrorEvent", "ApiEvent"]
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