diff --git a/src/index.d.ts b/src/index.d.ts
new file mode 100755
index 0000000..53e861c
--- /dev/null
+++ b/src/index.d.ts
@@ -0,0 +1,48 @@
+type notUndefined = boolean | number | string | object | null | notUndefined[]
+export type Resolver<Schema> = (
+  values: Schema[],
+  path: string[],
+  mergeSchemas: (schemas: Schema[]) => Schema,
+  options: MergerOptions
+) => notUndefined
+
+type PropertiesMerger<Schema> = {
+  properties: Resolver<Schema>
+  patternProperties: Resolver<Schema>
+  additionalProperties: Resolver<Schema>
+}
+type ItemsMerger<Schema> = {
+  items: Resolver<Schema>
+  additionalItems: Resolver<Schema>
+}
+export type CombinedResolver<Schema, Mergers> = (
+  values: Schema[],
+  path: string[],
+  mergers: Mergers,
+  options: MergerOptions
+) => notUndefined
+export interface Resolvers<Schema> {
+  [key: string]: Resolver<Schema>
+  properties?: CombinedResolver<Schema, PropertiesMerger>
+  items?: CombinedResolver<Schema, ItemsMerger>
+  defaultResolver?: Resolver<Schema>
+}
+
+export interface MergerOptions<Schema> {
+  /**
+   * @default false
+   */
+  ignoreAdditionalProperties?: boolean
+  resolvers?: Resolvers<Schema>
+  /**
+   * @default true
+   */
+  deep?: boolean
+}
+
+declare function merger<Schema> (
+  rootSchema: Schema,
+  options?: MergerOptions<Schema>
+): Schema
+
+export = merger