diff --git a/app/models.py b/app/models.py
index 598882e..52e14d7 100644
--- a/app/models.py
+++ b/app/models.py
@@ -2,69 +2,40 @@ from datetime import UTC, datetime
 from enum import StrEnum
 from uuid import UUID, uuid4
 
-from pydantic import BaseModel, ConfigDict, Field, HttpUrl, model_validator
-
-
-def now_utc() -> datetime:
-    return datetime.now(UTC)
+from pydantic import AnyHttpUrl, BaseModel, ConfigDict, Field
 
 
 class State(StrEnum):
-    NEVER_CHECKED = "never_checked"
+    UNKNOWN = "unknown"
     UP = "up"
     DOWN = "down"
     ERROR = "error"
-    BLOCKED = "blocked"
 
 
 class MonitorCreate(BaseModel):
     name: str = Field(min_length=1, max_length=100)
-    url: HttpUrl
-    expected_status: int = Field(default=200, ge=100, le=599)
+    url: AnyHttpUrl
 
 
 class MonitorUpdate(BaseModel):
     name: str | None = Field(default=None, min_length=1, max_length=100)
-    url: HttpUrl | None = None
-    expected_status: int | None = Field(default=None, ge=100, le=599)
-
-    @model_validator(mode="after")
-    def not_empty(self) -> "MonitorUpdate":
-        if not self.model_fields_set:
-            raise ValueError("at least one field is required")
-        return self
+    url: AnyHttpUrl | None = None
 
 
 class CurrentStatus(BaseModel):
-    model_config = ConfigDict(frozen=True)
-
-    state: State = State.NEVER_CHECKED
+    state: State = State.UNKNOWN
     checked_at: datetime | None = None
-    observed_status: int | None = None
-    latency_ms: float | None = None
+    status_code: int | None = None
+    latency_ms: float | None = Field(default=None, ge=0)
     error: str | None = None
 
 
 class Monitor(BaseModel):
-    model_config = ConfigDict(frozen=True)
+    model_config = ConfigDict(from_attributes=True)
 
     id: UUID = Field(default_factory=uuid4)
     name: str
-    url: HttpUrl
-    expected_status: int
-    created_at: datetime = Field(default_factory=now_utc)
-    updated_at: datetime = Field(default_factory=now_utc)
+    url: AnyHttpUrl
+    created_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
+    updated_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
     current_status: CurrentStatus = Field(default_factory=CurrentStatus)
-
-
-class CheckResult(CurrentStatus):
-    monitor_id: UUID
-
-
-class ErrorBody(BaseModel):
-    code: str
-    message: str
-
-
-class ErrorResponse(BaseModel):
-    error: ErrorBody