diff --git a/projects/fal/src/fal/api.py b/projects/fal/src/fal/api.py
index 9dba7c61..5005bd4b 100644
--- a/projects/fal/src/fal/api.py
+++ b/projects/fal/src/fal/api.py
@@ -142,6 +142,8 @@ def parse_key(cls, key: str, value: Any) -> tuple[Any, Any]:
             # Conda environment definition should be parsed before sending to serverless
             with open(value) as f:
                 return "env_dict", yaml.safe_load(f)
+        elif key == "image" and isinstance(value, ContainerImage):
+            return "image", value.to_dict()
         else:
             return key, value
 
diff --git a/projects/fal/src/fal/container.py b/projects/fal/src/fal/container.py
index 2f98f6c1..d97c8255 100644
--- a/projects/fal/src/fal/container.py
+++ b/projects/fal/src/fal/container.py
@@ -1,19 +1,49 @@
+from dataclasses import dataclass, field
+from typing import Dict, Literal
+
+Builder = Literal["depot", "service", "worker"]
+BUILDERS = {"depot", "service", "worker"}
+DEFAULT_BUILDER: Builder = "depot"
+
+
+@dataclass
 class ContainerImage:
     """ContainerImage represents a Docker image that can be built
     from a Dockerfile.
     """
 
-    _known_keys = {"dockerfile_str", "build_args", "registries", "builder"}
+    dockerfile_str: str
+    build_args: Dict[str, str] = field(default_factory=dict)
+    registries: Dict[str, Dict[str, str]] = field(default_factory=dict)
+    builder: Builder = field(default=DEFAULT_BUILDER)
+
+    def __post_init__(self) -> None:
+        if self.registries:
+            for registry in self.registries.values():
+                keys = registry.keys()
+                if "username" not in keys or "password" not in keys:
+                    raise ValueError(
+                        "Username and password are required for each registry"
+                    )
+
+        if self.builder not in BUILDERS:
+            raise ValueError(
+                f"Invalid builder: {self.builder}, must be one of {BUILDERS}"
+            )
 
     @classmethod
-    def from_dockerfile_str(cls, text: str, **kwargs):
-        # Check for unknown keys and return them as a dict.
-        return dict(
-            dockerfile_str=text,
-            **{k: v for k, v in kwargs.items() if k in cls._known_keys},
-        )
+    def from_dockerfile_str(cls, text: str, **kwargs) -> "ContainerImage":
+        return cls(dockerfile_str=text, **kwargs)
 
     @classmethod
-    def from_dockerfile(cls, path: str, **kwargs):
+    def from_dockerfile(cls, path: str, **kwargs) -> "ContainerImage":
         with open(path) as fobj:
             return cls.from_dockerfile_str(fobj.read(), **kwargs)
+
+    def to_dict(self) -> dict:
+        return {
+            "dockerfile_str": self.dockerfile_str,
+            "build_args": self.build_args,
+            "registries": self.registries,
+            "builder": self.builder,
+        }