diff --git a/eltro.d.ts b/eltro.d.ts
new file mode 100644
index 0000000..92ba843
--- /dev/null
+++ b/eltro.d.ts
@@ -0,0 +1,63 @@
+import NodeAssert from 'assert';
+
+type ExtendedAssert = {
+  notOk(value: unknown, message?: string | Error): void,
+  match(value: string, test: RegExp, message?: string | Error): void,
+  notMatch(value: string, test: RegExp, message?: string | Error): void,
+  throwsAndCatch(fn: () => unknown, message?: string | Error): Error,
+  equalWithMargin(value: number, test: number, margin?: number, message?: string | Error): void,
+  isFulfilled<T>(promise: Promise<T>, message?: string | Error): Promise<T>,
+  isRejected(promise: Promise<unknown>, message?: string | Error): Promise<unknown>,
+}
+
+export const assert: typeof NodeAssert & ExtendedAssert
+
+type Spy = {
+  (): unknown
+  lastCall: null | Array<unknown>
+  called: boolean
+  callCount: number
+  calls: Array<Array<unknown>>
+  findCall(fn: (args: Array<unknown>) => boolean): null | Array<unknown>
+  getCall(index: number): null | Array<unknown>
+  getCallN(index: number): null | Array<unknown>
+  onCall(index: number): Spy
+  onCallN(index: number): Spy
+  reset(): Spy
+  returns(data: unknown): Spy
+  throws(data: unknown): Spy
+  resolves(data: unknown): Spy
+  rejects(data: unknown): Spy
+  returnWith(fn: (...args: unknown[]) => unknown): Spy
+}
+
+export function spy(): Spy
+export function stub(fun?: (...args: unknown[]) => unknown): Spy
+
+type Test = {
+  timeout(timeout: number): void
+  skip(): void
+  only(): void
+}
+
+type TestResult = void | Promise<unknown>
+
+type Callback = {
+  (): void
+  wrap(fn: () => unknown): void
+  finish(fn: () => unknown): void
+}
+
+type Eltro = {
+  before(fn: () => TestResult): Test
+  after(fn: () => TestResult): Test
+  beforeEach(fn: () => TestResult): Test
+  afterEachEach(fn: () => TestResult): Test
+  describe(name: string, fn: () => void)
+  timeout(timeout: number): Eltro
+  skip(): Eltro
+  only(): Eltro
+  test(name: string, func: (cb?: Callback) => TestResult): Test
+}
+
+export const Eltro: Eltro
diff --git a/package.json b/package.json
index 1a1f67e..86c0dc4 100644
--- a/package.json
+++ b/package.json
@@ -1,8 +1,9 @@
 {
   "name": "eltro",
-  "version": "1.5.0",
+  "version": "1.6.0",
   "description": "Eltro is a tiny no-dependancy test framework for node",
   "main": "index.mjs",
+  "types": "eltro.d.ts",
   "scripts": {
     "echo": "echo helloworld",
     "echo:watch": "node cli.mjs --watch test --npm echo",