diff --git a/SQL.test-d.ts b/SQL.test-d.ts
deleted file mode 100644
index 356f66b..0000000
--- a/SQL.test-d.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-import SQL from '.'
-import { glue, map, SqlStatement } from '.'
-import { expectType, expectError } from 'tsd'
-
-expectType<SqlStatement>(SQL`SELECT 1`)
-expectType<SQL.SqlStatement>(SQL`SELECT 1`)
-expectType<SqlStatement>(SQL`SELECT `.append(SQL`1`))
-expectType<SQL.SqlStatement>(SQL`SELECT `.append(SQL`1`))
-expectType<SqlStatement>(glue([SQL`SELECT`, SQL`1`], ' '))
-expectType<SQL.SqlStatement>(SQL.glue([SQL`SELECT`, SQL`1`], ' '))
-expectType<SQL.SqlStatement>(SQL.map([1,2,3]))
-expectType<SQL.SqlStatement>(SQL.map([1,2,3], x => x**2))
-expectType<SQL.SqlStatement>(map([1,2,3]))
-expectType<SQL.SqlStatement>(map([1,2,3], x => x**2))
-expectType<string>(SQL`SELECT 1`.debug)
-expectType<string>(SQL`SELECT 1`.sql)
-expectType<string>(SQL`SELECT 1`.text)
-expectType<{ value: string }>(SQL.unsafe('string'))
-expectType<{ value: number }>(SQL.unsafe(1))
-expectType<{ value: string }>(SQL.quoteIdent('string'))
-expectError(SQL`SELECT `.append(`1`))
diff --git a/SQL.tst.ts b/SQL.tst.ts
new file mode 100644
index 0000000..fa5e474
--- /dev/null
+++ b/SQL.tst.ts
@@ -0,0 +1,21 @@
+import SQL from '.'
+import { glue, map, SqlStatement } from '.'
+import { expect } from 'tstyche'
+
+expect(SQL`SELECT 1`).type.toBe<SqlStatement>()
+expect(SQL`SELECT 1`).type.toBe<SQL.SqlStatement>()
+expect(SQL`SELECT `.append(SQL`1`)).type.toBe<SqlStatement>()
+expect(SQL`SELECT `.append(SQL`1`)).type.toBe<SQL.SqlStatement>()
+expect(glue([SQL`SELECT`, SQL`1`], ' ')).type.toBe<SqlStatement>()
+expect(SQL.glue([SQL`SELECT`, SQL`1`], ' ')).type.toBe<SQL.SqlStatement>()
+expect(SQL.map([1, 2, 3])).type.toBe<SQL.SqlStatement>()
+expect(SQL.map([1, 2, 3], x => x ** 2)).type.toBe<SQL.SqlStatement>()
+expect(map([1, 2, 3])).type.toBe<SQL.SqlStatement>()
+expect(map([1, 2, 3], x => x ** 2)).type.toBe<SQL.SqlStatement>()
+expect(SQL`SELECT 1`.debug).type.toBe<string>()
+expect(SQL`SELECT 1`.sql).type.toBe<string>()
+expect(SQL`SELECT 1`.text).type.toBe<string>()
+expect(SQL.unsafe('string')).type.toBe<{ value: string }>()
+expect(SQL.unsafe(1)).type.toBe<{ value: number }>()
+expect(SQL.quoteIdent('string')).type.toBe<{ value: string }>()
+expect(SQL`SELECT `.append).type.not.toBeCallableWith(`1`)
diff --git a/package.json b/package.json
index a087e8f..7ab1dd7 100644
--- a/package.json
+++ b/package.json
@@ -6,9 +6,9 @@
   "types": "./SQL.d.ts",
   "scripts": {
     "test": "node --test *.test.js",
-    "posttest": "tsd",
+    "posttest": "tstyche",
     "test:security": "node ./sqlmap/sqlmap.js",
-    "test:typescript": "tsd",
+    "test:typescript": "tstyche",
     "pretest:security": "git clone --depth=1 https://github.com/sqlmapproject/sqlmap node_modules/sqlmap && node ./sqlmap/db-init.js",
     "lint": "standard",
     "benchmark": "node benchmark/index.js"
@@ -32,7 +32,7 @@
     "pg": "^8.20.0",
     "sql-template-strings": "^2.2.2",
     "standard": "^17.1.2",
-    "tsd": "^0.33.0"
+    "tstyche": "^7.1.0"
   },
   "standard": {
     "ignore": [