diff --git a/client/src/common/types/entities.ts b/client/src/common/types/entities.ts
index fabef218..ccd33449 100644
--- a/client/src/common/types/entities.ts
+++ b/client/src/common/types/entities.ts
@@ -1,3 +1,73 @@
 // If a globally shared type or interface doesn't have a clear owner, put it here
 
 export {};
+
+export interface AnnotationColumn {
+  categories?: Category[];
+  name: string;
+  type: "string" | "float32" | "int32" | "categorical" | "boolean";
+  writable: boolean;
+}
+
+interface DataFrame {
+  nObs: number;
+  nVar: number;
+  // TODO(thuang): Not sure what other types are available
+  type: "float32";
+}
+
+export interface LayoutColumn {
+  dims: string[];
+  name: string;
+  // TODO(thuang): Not sure what other types are available
+  type: "float32";
+}
+interface RawLayout {
+  obs: LayoutColumn[];
+  var?: LayoutColumn[];
+}
+
+interface RawAnnotations {
+  obs: {
+    columns: AnnotationColumn[];
+    index: string;
+  };
+  var: {
+    columns: AnnotationColumn[];
+    index: string;
+  };
+}
+
+export interface RawSchema {
+  annotations: RawAnnotations;
+  dataframe: DataFrame;
+  layout: RawLayout;
+}
+
+interface Annotations extends RawAnnotations {
+  obsByName: { [name: string]: AnnotationColumn };
+  varByName: { [name: string]: AnnotationColumn };
+}
+
+interface Layout extends RawLayout {
+  obsByName: { [name: string]: LayoutColumn };
+  varByName: { [name: string]: LayoutColumn };
+}
+
+export interface Schema extends RawSchema {
+  annotations: Annotations;
+  layout: Layout;
+}
+
+export type TypedArray =
+  | Uint8Array
+  | Uint8ClampedArray
+  | Uint16Array
+  | Uint32Array
+  | Int8Array
+  | Int16Array
+  | Int32Array
+  | Float32Array
+  | Float64Array;
+
+export type NumericArray = TypedArray | Array<number>;