diff --git a/eslint.config.js b/eslint.config.js
index 5212dc93..e66d9015 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -1,3 +1,5 @@
 'use strict'
 
-module.exports = require('neostandard')({})
+module.exports = require('neostandard')({
+  ts: true
+})
diff --git a/index.d.ts b/index.d.ts
index d4aae86f..dde8cb24 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,23 +1,18 @@
-// Type definitions for pino-pretty 7.0
 // Project: https://github.com/pinojs/pino-pretty#readme
 // Definitions by: Adam Vigneaux <https://github.com/AdamVig>
 //                 tearwyx <https://github.com/tearwyx>
-// Minimum TypeScript Version: 3.0
 
 /// <reference types="node" />
 
-import { Transform } from 'node:stream';
-import { OnUnknown } from 'pino-abstract-transport';
+import { Transform } from 'node:stream'
+import { OnUnknown } from 'pino-abstract-transport'
 // @ts-ignore fall back to any if pino is not available, i.e. when running pino tests
-import { DestinationStream, Level } from 'pino';
-import * as Colorette from "colorette";
+import { DestinationStream, Level } from 'pino'
+import * as Colorette from 'colorette'
 
-type LogDescriptor = Record<string, unknown>;
-
-declare function PinoPretty(options?: PinoPretty.PrettyOptions): PinoPretty.PrettyStream;
+declare function PinoPretty (options?: PinoPretty.PrettyOptions): PinoPretty.PrettyStream
 declare namespace PinoPretty {
-
-  function colorizerFactory(
+  export function colorizerFactory (
     useColors?: boolean,
     customColors?: [number, string][],
     useOnlyCustomProps?: boolean,
@@ -33,9 +28,9 @@ declare namespace PinoPretty {
     greyMessage: (input: string | number) => string,
   }
 
-  function prettyFactory(options: PrettyOptions): (inputData: any) => string
+  export function prettyFactory (options: PrettyOptions): (inputData: any) => string
 
-  interface PrettyOptions {
+  export interface PrettyOptions {
     /**
      * Hide objects from output (but not error object).
      * @default false
@@ -197,7 +192,7 @@ declare namespace PinoPretty {
      *
      * Not required when used with pino >= 8.21.0
      */
-    customLevels?: string|object;
+    customLevels?: string | object;
     /**
      * Change the level colors to an user custom preset.
      *
@@ -207,7 +202,7 @@ declare namespace PinoPretty {
      * @example ( CSV ) customColors: 'info:white,some_level:red'
      * @example ( Object ) customColors: { info: 'white', some_level: 'red' }
      */
-    customColors?: string|object;
+    customColors?: string | object;
     /**
      * Only use custom levels and colors (if provided); else fallback to default levels and colors.
      *
@@ -216,19 +211,17 @@ declare namespace PinoPretty {
     useOnlyCustomProps?: boolean;
   }
 
-  function build(options: PrettyOptions): PrettyStream;
+  export function build (options?: PrettyOptions): PrettyStream
 
-  type Prettifier = (inputData: string | object, key: string, log: object, extras: PrettifierExtras) => string;
-  type PrettifierExtras = {colors: Colorette.Colorette, label: string, labelColorized: string};
-  type MessageFormatFunc = (log: LogDescriptor, messageKey: string, levelLabel: string, extras: PrettifierExtras) => string;
-  type PrettyStream = Transform & OnUnknown;
-  type ColorizerFactory = typeof colorizerFactory;
-  type PrettyFactory = typeof prettyFactory;
-  type Build = typeof build;
+  type PrettifierExtras = { colors: Colorette.Colorette, label: string, labelColorized: string }
+  export type Prettifier = (inputData: string | object, key: string, log: object, extras: PrettifierExtras) => string
+  export type MessageFormatFunc = (log: Record<string, unknown>, messageKey: string, levelLabel: string, extras: Pick<PrettifierExtras, 'colors'>) => string
+  export type PrettyStream = Transform & OnUnknown
 
   // @ts-ignore
-  export const isColorSupported = Colorette.isColorSupported;
-  export { build, PinoPretty, PrettyOptions, PrettyStream, colorizerFactory, prettyFactory };
+  export const isColorSupported = Colorette.isColorSupported
+
+  export { PinoPretty }
 }
 
-export = PinoPretty;
+export = PinoPretty
diff --git a/package.json b/package.json
index e2020271..af8d2763 100644
--- a/package.json
+++ b/package.json
@@ -9,11 +9,11 @@
     "pino-pretty": "./bin.js"
   },
   "scripts": {
-    "ci": "eslint && borp --check-coverage && npm run test-types",
+    "ci": "eslint && borp --check-coverage && npm run test:types",
     "lint": "eslint",
     "lint:fix": "eslint --fix",
     "test": "borp",
-    "test-types": "tsc && tsd && attw --pack .",
+    "test:types": "tstyche && attw --pack .",
     "test:watch": "borp -w --reporter gh",
     "test:report": "c8 --reporter html borp"
   },
@@ -53,14 +53,12 @@
     "borp": "^1.0.0",
     "eslint": "^9.39.1",
     "fastbench": "^1.0.1",
+    "fastify-tsconfig": "^3.0.0",
     "neostandard": "^0.12.2",
     "pino": "^10.1.0",
     "rimraf": "^6.1.2",
     "semver": "^7.6.0",
-    "tsd": "^0.33.0",
+    "tstyche": "^6.2.0",
     "typescript": "^5.9.3"
-  },
-  "tsd": {
-    "directory": "./test/types"
   }
 }
diff --git a/test/types/exports.tst.ts b/test/types/exports.tst.ts
new file mode 100644
index 00000000..14073501
--- /dev/null
+++ b/test/types/exports.tst.ts
@@ -0,0 +1,15 @@
+import { expect, test } from 'tstyche'
+
+import type PinoPretty from '../../index.js'
+import PinoPrettyDefault, { PinoPretty as PinoPrettyNamed } from '../../index.js'
+import * as PinoPrettyStar from '../../index.js'
+import PinoPrettyCjsImport = require('../../index.js')
+
+declare const options: PinoPretty.PrettyOptions
+
+test('exports', () => {
+  expect(PinoPrettyDefault(options)).type.toBe<PinoPretty.PrettyStream>()
+  expect(PinoPrettyNamed(options)).type.toBe<PinoPretty.PrettyStream>()
+  expect(PinoPrettyStar.PinoPretty(options)).type.toBe<PinoPretty.PrettyStream>()
+  expect(PinoPrettyCjsImport.PinoPretty(options)).type.toBe<PinoPretty.PrettyStream>()
+})
diff --git a/test/types/pino-pretty.test-d.ts b/test/types/pino-pretty.test-d.ts
deleted file mode 100644
index 8649edc3..00000000
--- a/test/types/pino-pretty.test-d.ts
+++ /dev/null
@@ -1,58 +0,0 @@
-import { expectType } from "tsd";
-
-import pretty from "../../";
-import PinoPretty, {
-  PinoPretty as PinoPrettyNamed,
-  PrettyOptions,
-  colorizerFactory,
-  prettyFactory
-} from "../../";
-import PinoPrettyDefault from "../../";
-import * as PinoPrettyStar from "../../";
-import PinoPrettyCjsImport = require("../../");
-import PrettyStream = PinoPretty.PrettyStream;
-const PinoPrettyCjs = require("../../");
-
-const options: PinoPretty.PrettyOptions = {
-  colorize: true,
-  crlf: false,
-  errorLikeObjectKeys: ["err", "error"],
-  errorProps: "",
-  hideObject: true,
-  levelKey: "level",
-  levelLabel: "foo",
-  messageFormat: false,
-  ignore: "",
-  levelFirst: false,
-  messageKey: "msg",
-  timestampKey: "timestamp",
-  minimumLevel: "trace",
-  translateTime: "UTC:h:MM:ss TT Z",
-  singleLine: false,
-  customPrettifiers: {
-    key: (value) => {
-      return value.toString().toUpperCase();
-    },
-    level: (level, levelKey, log, { label, labelColorized, colors }) => {
-      return level.toString();
-    },
-    foo: (value, key, log, { colors }) => {
-      return value.toString();
-    }
-  },
-  customLevels: 'verbose:5',
-  customColors: 'default:white,verbose:gray',
-  sync: false,
-  destination: 2,
-  append: true,
-  mkdir: true,
-  useOnlyCustomProps: false,
-};
-
-expectType<PrettyStream>(pretty()); // #326
-expectType<PrettyStream>(pretty(options));
-expectType<PrettyStream>(PinoPrettyNamed(options));
-expectType<PrettyStream>(PinoPrettyDefault(options));
-expectType<PrettyStream>(PinoPrettyStar.PinoPretty(options));
-expectType<PrettyStream>(PinoPrettyCjsImport.PinoPretty(options));
-expectType<any>(PinoPrettyCjs(options));
diff --git a/test/types/pino-pretty.tst.ts b/test/types/pino-pretty.tst.ts
new file mode 100644
index 00000000..8f1e591f
--- /dev/null
+++ b/test/types/pino-pretty.tst.ts
@@ -0,0 +1,140 @@
+import { expect, test } from 'tstyche'
+
+import colorette from 'colorette'
+import pino from 'pino'
+import pretty, {
+  build,
+  colorizerFactory,
+  isColorSupported,
+  MessageFormatFunc,
+  PinoPretty,
+  Prettifier,
+  prettyFactory,
+  PrettyOptions,
+  PrettyStream
+} from '../../index.js'
+
+declare const options: PrettyOptions
+
+test('default export', () => {
+  expect(pretty()).type.toBe<PrettyStream>()
+  expect(pretty(options)).type.toBe<PrettyStream>()
+})
+
+test('build', () => {
+  expect(build()).type.toBe<PrettyStream>()
+  expect(build(options)).type.toBe<PrettyStream>()
+})
+
+test('PinoPretty', () => {
+  expect(PinoPretty()).type.toBe<PrettyStream>()
+  expect(PinoPretty(options)).type.toBe<PrettyStream>()
+})
+
+test('PrettyStream', () => {
+  const stream = pretty()
+  pino(stream)
+
+  expect<PrettyStream>().type.toBeAssignableTo<pino.DestinationStream>()
+})
+
+test('prettyFactory', () => {
+  expect(prettyFactory(options)).type.toBe<(inputData: any) => string>()
+  expect(prettyFactory).type.not.toBeCallableWith()
+})
+
+test('colorizerFactory', () => {
+  const colorizer = colorizerFactory()
+
+  let useColors: boolean | undefined
+  expect(colorizerFactory(useColors)).type.toBe(colorizer)
+
+  let customColors: [number, string][] | undefined
+  expect(colorizerFactory(undefined, customColors)).type.toBe(colorizer)
+
+  let useOnlyCustomProps: boolean | undefined
+  expect(colorizerFactory(undefined, undefined, useOnlyCustomProps)).type.toBe(colorizer)
+
+  const input: string | number = ''
+  expect(colorizer.message(input)).type.toBe<string>()
+  expect(colorizer.greyMessage(input)).type.toBe<string>()
+
+  let level: string | number | undefined
+  expect(colorizer(level)).type.toBe<string>()
+
+  let customLevels: { [level: number]: string } | undefined
+  expect(colorizer(undefined, { customLevels })).type.toBe<string>()
+
+  let customLevelNames: { [name: string]: number } | undefined
+  expect(colorizer(undefined, { customLevelNames })).type.toBe<string>()
+})
+
+test('isColorSupported', () => {
+  expect(isColorSupported).type.toBe<boolean>()
+})
+
+test('PrettyOptions', () => {
+  expect<PrettyOptions>().type.toBeAssignableFrom({ colorize: true })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ colorizeObjects: true })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ crlf: false })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ errorLikeObjectKeys: ['err', 'error'] })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ errorProps: '' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ levelFirst: false })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ messageKey: 'msg' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ levelKey: 'level' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ messageFormat: false as const })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ messageFormat: '{levelLabel} - {pid} - url:{req.url}' })
+
+  const messageFormat: MessageFormatFunc = (log, messageKey, levelLabel, { colors }) => {
+    expect(log).type.toBe<Record<string, unknown>>()
+    expect(messageKey).type.toBe<string>()
+    expect(levelLabel).type.toBe<string>()
+    expect(colors).type.toBe<colorette.Colorette>()
+
+    return ''
+  }
+
+  expect<PrettyOptions>().type.toBeAssignableFrom({ messageFormat })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ timestampKey: 'time' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ translateTime: false })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ translateTime: 'SYS:standard' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ ignore: 'pid,hostname' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ include: 'level,time' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ hideObject: false })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ singleLine: false })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ customColors: 'err:red,info:blue' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ customColors: { info: 'white', some_level: 'red' } })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ customLevels: 'err:99,info:1' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ customLevels: { info: 10, some_level: 40 } })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ levelLabel: 'levelLabel' })
+  expect<PrettyOptions>().type.toBeAssignableFrom<{ minimumLevel: pino.Level }>()
+  expect<PrettyOptions>().type.toBeAssignableFrom({ useOnlyCustomProps: true })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ destination: '1' })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ destination: 1 })
+  expect<PrettyOptions>().type.toBeAssignableFrom<{ destination: pino.DestinationStream }>()
+  expect<PrettyOptions>().type.toBeAssignableFrom<{ destination: NodeJS.WritableStream }>()
+
+  expect<PrettyOptions>().type.toBeAssignableFrom({ sync: false })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ append: true })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ mkdir: true })
+
+  const levelPrettifier: Prettifier = (input, key, log, { colors, label, labelColorized }) => {
+    expect(input).type.toBe<string | object>()
+    expect(key).type.toBe<string>()
+    expect(log).type.toBe<object>()
+    expect(colors).type.toBe<colorette.Colorette>()
+    expect(label).type.toBe<string>()
+    expect(labelColorized).type.toBe<string>()
+
+    return input.toString()
+  }
+
+  const customPrettifiers: Record<string, Prettifier> = {
+    time: timestamp => `🕰 ${timestamp}`,
+    level: logLevel => `LEVEL: ${logLevel}`,
+    name: (name, _key, _log, { colors }) => `${colors.blue(name.toString())}`,
+  }
+
+  expect<PrettyOptions>().type.toBeAssignableFrom({ customPrettifiers: { level: levelPrettifier } })
+  expect<PrettyOptions>().type.toBeAssignableFrom({ customPrettifiers })
+})
diff --git a/test/types/tsconfig.json b/test/types/tsconfig.json
new file mode 100644
index 00000000..f1f0192b
--- /dev/null
+++ b/test/types/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "extends": "fastify-tsconfig",
+  "compilerOptions": {
+    "noEmit": true,
+    "noUnusedLocals": false,
+    "noUnusedParameters": false,
+    "types": []
+  }
+}
diff --git a/tsconfig.json b/tsconfig.json
deleted file mode 100644
index 8a9ab13b..00000000
--- a/tsconfig.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-  "compilerOptions": {
-    "target": "es6",
-    "lib": [ "es2015" ],
-    "module": "commonjs",
-    "noEmit": true,
-    "strict": true,
-    "esModuleInterop": true
-  },
-  "include": [
-    "./test/types/pino-pretty.test.d.ts",
-    "./index.d.ts"
-  ]
-}