diff --git a/package.json b/package.json
index 2fa6683..e1a2762 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "lint:fix": "eslint --fix",
     "test": "nyc npm run test:unit && npm run test:typescript",
     "test:unit": "tape \"test/*.test.js\"",
-    "test:typescript": "tsd",
+    "test:typescript": "tstyche",
     "test:browser": "airtap test/*.test.js"
   },
   "repository": {
@@ -69,6 +69,6 @@
     "nyc": "^18.0.0",
     "playwright": "^1.43.1",
     "tape": "^5.7.5",
-    "tsd": "^0.33.0"
+    "tstyche": "^7.1.0"
   }
 }
diff --git a/types/index.test-d.ts b/types/index.tst.ts
similarity index 52%
rename from types/index.test-d.ts
rename to types/index.tst.ts
index c12e348..3c99893 100644
--- a/types/index.test-d.ts
+++ b/types/index.tst.ts
@@ -1,14 +1,16 @@
-import { expectType, expectError } from 'tsd'
+/// <reference types="node" />
+
+import { expect } from 'tstyche'
 import sjson from '..'
 
-expectError(sjson.parse(null))
-expectType<any>(sjson.parse('{"anything":0}'))
+expect(sjson.parse).type.not.toBeCallableWith(null)
+expect(sjson.parse('{"anything":0}')).type.toBe<any>()
 
 sjson.parse('"test"', null, { protoAction: 'remove' })
-expectError(sjson.parse('"test"', null, { protoAction: 'incorrect' }))
+expect(sjson.parse).type.not.toBeCallableWith('"test"', null, { protoAction: 'incorrect' })
 sjson.parse('"test"', null, { constructorAction: 'ignore' })
-expectError(sjson.parse('"test"', null, { constructorAction: 'incorrect' }))
-expectError(sjson.parse('"test"', { constructorAction: 'incorrect' }))
+expect(sjson.parse).type.not.toBeCallableWith('"test"', null, { constructorAction: 'incorrect' })
+expect(sjson.parse).type.not.toBeCallableWith('"test"', { constructorAction: 'incorrect' })
 sjson.parse('test', { constructorAction: 'remove' })
 sjson.parse('test', { protoAction: 'ignore' })
 sjson.parse('test', () => {}, { protoAction: 'ignore', constructorAction: 'remove' })
@@ -16,11 +18,11 @@ sjson.parse('"test"', null, { safe: true })
 sjson.parse('"test"', { safe: true })
 sjson.parse('test', () => {}, { safe: false })
 sjson.parse('test', { protoAction: 'remove', safe: true })
-expectError(sjson.parse('"test"', null, { safe: 'incorrect' }))
+expect(sjson.parse).type.not.toBeCallableWith('"test"', null, { safe: 'incorrect' })
 
 sjson.safeParse('"test"', null)
 sjson.safeParse('"test"')
-expectError(sjson.safeParse(null))
+expect(sjson.safeParse).type.not.toBeCallableWith(null)
 
 sjson.scan({}, { protoAction: 'remove' })
 sjson.scan({}, { protoAction: 'ignore' })
@@ -29,15 +31,15 @@ sjson.scan({}, { constructorAction: 'ignore' })
 sjson.scan([], {})
 sjson.scan({}, { safe: true })
 sjson.scan({}, { protoAction: 'remove', safe: false })
-expectError(sjson.scan({}, { safe: 'incorrect' }))
+expect(sjson.scan).type.not.toBeCallableWith({}, { safe: 'incorrect' })
 
 declare const input: Buffer
 sjson.parse(input)
 sjson.safeParse(input)
 
-sjson.parse('{"anything":0}', (key, value) => {
-  expectType<string>(key)
+sjson.parse('{"anything":0}', (key, _value) => {
+  expect(key).type.toBe<string>()
 })
-sjson.safeParse('{"anything":0}', (key, value) => {
-  expectType<string>(key)
+sjson.safeParse('{"anything":0}', (key, _value) => {
+  expect(key).type.toBe<string>()
 })