diff --git a/src/Message/Factory/Factory.php b/src/Message/Factory/Factory.php
index f4e75c1..b0b79ad 100644
--- a/src/Message/Factory/Factory.php
+++ b/src/Message/Factory/Factory.php
@@ -182,7 +182,7 @@ public function createUriFromArray(array $server): Uri
         }
 
         if (isset($server['SERVER_PORT'])) {
-            $uri = $uri->withPort($server['SERVER_PORT']);
+            $uri = $uri->withPort((int) $server['SERVER_PORT']);
         }
 
         if (isset($server['REQUEST_URI'])) {
diff --git a/src/Message/MessageTrait.php b/src/Message/MessageTrait.php
index 6094af1..fd1eadb 100644
--- a/src/Message/MessageTrait.php
+++ b/src/Message/MessageTrait.php
@@ -40,7 +40,7 @@ public function getProtocolVersion(): string
      *
      * @return self
      */
-    public function withProtocolVersion($version): self
+    public function withProtocolVersion(string $version): self
     {
         $this->validateProtocolVersion($version);
 
@@ -69,12 +69,8 @@ public function getHeaders(): array
      *
      * @return bool
      */
-    public function hasHeader($name): bool
+    public function hasHeader(string $name): bool
     {
-        if (!\is_string($name)) {
-            throw new \InvalidArgumentException('Header name must be a string');
-        }
-
         return isset($this->headerNames[\mb_strtolower($name)]);
     }
 
@@ -85,12 +81,8 @@ public function hasHeader($name): bool
      *
      * @return array
      */
-    public function getHeader($name): array
+    public function getHeader(string $name): array
     {
-        if (!\is_string($name)) {
-            throw new \InvalidArgumentException('Header name must be a string');
-        }
-
         $name = \mb_strtolower($name);
 
         if (!isset($this->headerNames[$name])) {
@@ -109,7 +101,7 @@ public function getHeader($name): array
      *
      * @return string
      */
-    public function getHeaderLine($name): string
+    public function getHeaderLine(string $name): string
     {
         return \implode(', ', $this->getHeader($name));
     }
@@ -122,9 +114,9 @@ public function getHeaderLine($name): string
      *
      * @return self
      */
-    public function withHeader($name, $value): self
+    public function withHeader(string $name, $value): self
     {
-        if (!\is_string($name) || $name === '') {
+        if ($name === '') {
             throw new \InvalidArgumentException('Header name must be non-empty string');
         }
 
@@ -149,9 +141,9 @@ public function withHeader($name, $value): self
      *
      * @return self
      */
-    public function withAddedHeader($name, $value): self
+    public function withAddedHeader(string $name, $value): self
     {
-        if (!\is_string($name) || $name === '') {
+        if ($name === '') {
             throw new \InvalidArgumentException('Header name must be non-empty string');
         }
 
@@ -168,9 +160,9 @@ public function withAddedHeader($name, $value): self
      *
      * @return self
      */
-    public function withoutHeader($name): self
+    public function withoutHeader(string $name): self
     {
-        if (!\is_string($name) || $name === '') {
+        if ($name === '') {
             throw new \InvalidArgumentException('Header name must be non-empty string');
         }
 
diff --git a/src/Message/RequestTrait.php b/src/Message/RequestTrait.php
index b53db83..cbe1e73 100644
--- a/src/Message/RequestTrait.php
+++ b/src/Message/RequestTrait.php
@@ -129,7 +129,7 @@ public function getMethod(): string
      *
      * @return self
      */
-    public function withMethod($method): self
+    public function withMethod(string $method): self
     {
         $method = $this->filterMethod($method);
 
@@ -155,12 +155,8 @@ public function getUri(): UriInterface
      *
      * @return self
      */
-    public function withUri(UriInterface $uri, $preserveHost = false): self
+    public function withUri(UriInterface $uri, bool $preserveHost = false): self
     {
-        if (!\is_bool($preserveHost)) {
-            throw new \InvalidArgumentException('Preserve Host must be a boolean');
-        }
-
         if ($this->uri === $uri) {
             return $this;
         }
@@ -182,12 +178,8 @@ public function withUri(UriInterface $uri, $preserveHost = false): self
      *
      * @return string
      */
-    protected function filterMethod($method): string
+    protected function filterMethod(string $method): string
     {
-        if (!\is_string($method)) {
-            throw new \InvalidArgumentException('Method must be a string');
-        }
-
         if (!\in_array($method, static::$methods, true)) {
             throw new \InvalidArgumentException(\sprintf('Method %s is invalid', $method));
         }
diff --git a/src/Message/Response.php b/src/Message/Response.php
index 6d11e20..8fc5067 100644
--- a/src/Message/Response.php
+++ b/src/Message/Response.php
@@ -233,12 +233,8 @@ public function getStatusCode(): int
      *
      * @return Response
      */
-    public function withStatus($code, $reasonPhrase = ''): self
+    public function withStatus(int $code, string $reasonPhrase = ''): self
     {
-        if (!\is_int($code)) {
-            throw new \InvalidArgumentException('Status code has to be an integer');
-        }
-
         if (!isset(static::PHRASES[$code])) {
             throw new \InvalidArgumentException('Status code has to be an integer between 100 and 799');
         }
diff --git a/src/Message/ServerRequest.php b/src/Message/ServerRequest.php
index dcdbaad..fcc81d9 100644
--- a/src/Message/ServerRequest.php
+++ b/src/Message/ServerRequest.php
@@ -182,12 +182,8 @@ public function getAttributes(): array
      *
      * @return mixed|null
      */
-    public function getAttribute($name, $default = null)
+    public function getAttribute(string $name, $default = null)
     {
-        if (!\is_string($name)) {
-            throw new \InvalidArgumentException('Name must be a string');
-        }
-
         if (!\array_key_exists($name, $this->attributes)) {
             return $default;
         }
@@ -203,12 +199,8 @@ public function getAttribute($name, $default = null)
      *
      * @return self
      */
-    public function withAttribute($name, $value): self
+    public function withAttribute(string $name, $value): self
     {
-        if (!\is_string($name)) {
-            throw new \InvalidArgumentException('Name must be a string');
-        }
-
         $new = clone $this;
         $new->attributes[$name] = $value;
 
@@ -222,12 +214,8 @@ public function withAttribute($name, $value): self
      *
      * @return self
      */
-    public function withoutAttribute($name): self
+    public function withoutAttribute(string $name): self
     {
-        if (!\is_string($name)) {
-            throw new \InvalidArgumentException('Name must be a string');
-        }
-
         if (!\array_key_exists($name, $this->attributes)) {
             return $this;
         }
diff --git a/src/Message/Stream.php b/src/Message/Stream.php
index bcdf355..d0008de 100644
--- a/src/Message/Stream.php
+++ b/src/Message/Stream.php
@@ -208,12 +208,8 @@ public function isWritable(): bool
      *
      * @return int
      */
-    public function write($string)
+    public function write(string $string): int
     {
-        if (!\is_string($string)) {
-            throw new \InvalidArgumentException('Data must be a string');
-        }
-
         if (!$this->writable) {
             throw new \RuntimeException('Cannot write to a non-writable stream');
         }
diff --git a/src/Message/UploadedFile.php b/src/Message/UploadedFile.php
index dd5be84..d930dfa 100644
--- a/src/Message/UploadedFile.php
+++ b/src/Message/UploadedFile.php
@@ -90,7 +90,7 @@ public function getStream(): StreamInterface
      * @throws \InvalidArgumentException
      * @throws \RuntimeException
      */
-    public function moveTo($targetPath): void
+    public function moveTo(string $targetPath): void
     {
         $this->validateActive();
 
diff --git a/src/Message/Uri.php b/src/Message/Uri.php
index 422e06e..d87d6ef 100644
--- a/src/Message/Uri.php
+++ b/src/Message/Uri.php
@@ -139,7 +139,7 @@ public function getFragment(): string
      *
      * @return self
      */
-    public function withScheme($scheme): self
+    public function withScheme(string $scheme): self
     {
         $scheme = $this->filterScheme($scheme);
 
@@ -162,7 +162,7 @@ public function withScheme($scheme): self
      *
      * @return self
      */
-    public function withUserInfo($user, $password = null): self
+    public function withUserInfo(string $user, ?string $password = null): self
     {
         $info = $this->filterUser($user);
         $password = $this->filterPass($password);
@@ -188,7 +188,7 @@ public function withUserInfo($user, $password = null): self
      *
      * @return self
      */
-    public function withHost($host): self
+    public function withHost(string $host): self
     {
         $host = $this->filterHost($host);
 
@@ -209,7 +209,7 @@ public function withHost($host): self
      *
      * @return self
      */
-    public function withPort($port): self
+    public function withPort(?int $port): self
     {
         $port = $this->filterPort($port);
 
@@ -230,7 +230,7 @@ public function withPort($port): self
      *
      * @return self
      */
-    public function withPath($path): self
+    public function withPath(string $path): self
     {
         $path = $this->filterPath($path);
 
@@ -251,7 +251,7 @@ public function withPath($path): self
      *
      * @return self
      */
-    public function withQuery($query): self
+    public function withQuery(string $query): self
     {
         $query = $this->filterQueryAndFragment($query);
 
@@ -272,7 +272,7 @@ public function withQuery($query): self
      *
      * @return self
      */
-    public function withFragment($fragment): self
+    public function withFragment(string $fragment): self
     {
         $fragment = $this->filterQueryAndFragment($fragment);
 
@@ -436,12 +436,8 @@ protected static function isNonStandardPort(string $scheme, int $port): bool
      *
      * @return string
      */
-    protected function filterScheme($scheme): string
+    protected function filterScheme(string $scheme): string
     {
-        if (!\is_string($scheme)) {
-            throw new \InvalidArgumentException('Scheme must be a string');
-        }
-
         return \mb_strtolower($scheme);
     }
 
@@ -452,12 +448,8 @@ protected function filterScheme($scheme): string
      *
      * @return string
      */
-    protected function filterUser($user): string
+    protected function filterUser(string $user): string
     {
-        if (!\is_string($user)) {
-            throw new \InvalidArgumentException('User must be a string');
-        }
-
         return $user;
     }
 
@@ -468,12 +460,8 @@ protected function filterUser($user): string
      *
      * @return string
      */
-    protected function filterPass($pass): ?string
+    protected function filterPass(?string $pass): ?string
     {
-        if ($pass !== null && !\is_string($pass)) {
-            throw new \InvalidArgumentException('Password must be a string or NULL');
-        }
-
         return $pass;
     }
 
@@ -484,12 +472,8 @@ protected function filterPass($pass): ?string
      *
      * @return string
      */
-    protected function filterHost($host): string
+    protected function filterHost(string $host): string
     {
-        if (!\is_string($host)) {
-            throw new \InvalidArgumentException('Host must be a string');
-        }
-
         return \mb_strtolower($host);
     }
 
@@ -500,13 +484,12 @@ protected function filterHost($host): string
      *
      * @return int|null
      */
-    protected function filterPort($port): ?int
+    protected function filterPort(?int $port): ?int
     {
         if ($port === null) {
             return null;
         }
 
-        $port = (int) $port;
         if ($port < 1 || $port > 65535) {
             throw new \InvalidArgumentException(\sprintf('Invalid port: %d. Must be between 1 and 65535', $port));
         }
@@ -525,12 +508,8 @@ protected function filterPort($port): ?int
      *
      * @return string
      */
-    protected function filterPath($path): string
+    protected function filterPath(string $path): string
     {
-        if (!\is_string($path)) {
-            throw new \InvalidArgumentException('Path must be a string');
-        }
-
         return \preg_replace_callback(
             static::getPatternForFilteringPath(),
             [__CLASS__, 'rawurlencodeMatchZero'],
@@ -545,12 +524,8 @@ protected function filterPath($path): string
      *
      * @return string
      */
-    protected function filterQueryAndFragment($str): string
+    protected function filterQueryAndFragment(string $str): string
     {
-        if (!\is_string($str)) {
-            throw new \InvalidArgumentException('Query and fragment must be a string');
-        }
-
         return \preg_replace_callback(
             static::getPatternForFilteringQueryAndFragment(),
             [__CLASS__, 'rawurlencodeMatchZero'],
diff --git a/tests/RequestTest.php b/tests/RequestTest.php
index 7b0a844..ba18548 100644
--- a/tests/RequestTest.php
+++ b/tests/RequestTest.php
@@ -189,24 +189,6 @@ public function testWithMethod(): void
         static::assertSame('PATCH', $r->getMethod());
     }
 
-    public function testWithUriPreserveHostMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Preserve Host must be a boolean');
-
-        $r = new Request('GET', 'https://foo.com:8124/bar');
-        $r->withUri(new Uri(), null);
-    }
-
-    public function testWithMethodMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Method must be a string');
-
-        $r = new Request('GET', 'https://foo.com:8124/bar');
-        $r->withMethod(null);
-    }
-
     public function testWithMethodMustBeValidMethod(): void
     {
         $this->expectException(\InvalidArgumentException::class);
diff --git a/tests/ResponseTest.php b/tests/ResponseTest.php
index 899cfb3..03a322d 100644
--- a/tests/ResponseTest.php
+++ b/tests/ResponseTest.php
@@ -46,17 +46,6 @@ public function testConstructStatusCantBeNumericString(): void
         new Response('-404.4');
     }
 
-    public function testWithStatusCantBeNumericString(): void
-    {
-        $r = new Response(404);
-        static::assertSame(404, $r->getStatusCode());
-        static::assertSame('Not Found', $r->getReasonPhrase());
-
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Status code has to be an integer');
-        $r->withStatus('201');
-    }
-
     public function testCanConstructWithHeaders(): void
     {
         $r = new Response(200, ['Foo' => 'Bar']);
@@ -269,33 +258,6 @@ public function trimmedHeaderValues(): array
         ];
     }
 
-    public function testHasHeaderMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Header name must be a string');
-
-        $r = new Response();
-        static::assertSame($r, $r->hasHeader(null));
-    }
-
-    public function testGetHeaderMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Header name must be a string');
-
-        $r = new Response();
-        static::assertSame($r, $r->getHeader(null));
-    }
-
-    public function testGetHeaderLineMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Header name must be a string');
-
-        $r = new Response();
-        static::assertSame($r, $r->getHeaderLine(null));
-    }
-
     public function testWithHeaderNameMustHaveCorrectType(): void
     {
         $this->expectException(\InvalidArgumentException::class);
@@ -389,24 +351,6 @@ public function testHeaderValuesAreTrimmed(Response $r): void
         static::assertSame(['Foo'], $r->getHeader('OWS'));
     }
 
-    public function testWithStatusCodeMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Status code has to be an integer');
-
-        $r = new Response();
-        $r->withStatus([]);
-    }
-
-    public function testWithStatusReasonPhraseMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Status code has to be an integer between 100 and 799');
-
-        $r = new Response();
-        $r->withStatus(9, []);
-    }
-
     /**
      * @runInSeparateProcess
      */
diff --git a/tests/ServerRequestTest.php b/tests/ServerRequestTest.php
index 4ef0aac..ea987bf 100644
--- a/tests/ServerRequestTest.php
+++ b/tests/ServerRequestTest.php
@@ -546,30 +546,6 @@ public function testNullAttribute(): void
         static::assertSame('different-default', $requestWithoutAttribute->getAttribute('name', 'different-default'));
     }
 
-    public function testGetAttributeMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Name must be a string');
-
-        (new ServerRequest('GET', '/'))->getAttribute([]);
-    }
-
-    public function testWithAttributeMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Name must be a string');
-
-        (new ServerRequest('GET', '/'))->withAttribute([], null);
-    }
-
-    public function testWithoutAttributeMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Name must be a string');
-
-        (new ServerRequest('GET', '/'))->withoutAttribute([]);
-    }
-
     public function testWithParsedBodyMustHaveCorrectType(): void
     {
         $this->expectException(\InvalidArgumentException::class);
diff --git a/tests/StreamTest.php b/tests/StreamTest.php
index f40902b..b08f504 100644
--- a/tests/StreamTest.php
+++ b/tests/StreamTest.php
@@ -209,16 +209,6 @@ public function testSeekRaiseExceptionUnableToSeek(): void
         $stream->seek(1, 90909090);
     }
 
-    public function testWriteRaiseExceptionData(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Data must be a string');
-
-        $handle = \fopen('php://temp', 'w+');
-        $stream = Stream::create($handle);
-        $stream->write(0);
-    }
-
     public function testReadRaiseExceptionLength(): void
     {
         $this->expectException(\InvalidArgumentException::class);
diff --git a/tests/UploadedFileTest.php b/tests/UploadedFileTest.php
index 8a7054c..a883d17 100644
--- a/tests/UploadedFileTest.php
+++ b/tests/UploadedFileTest.php
@@ -184,14 +184,7 @@ public function testSuccessful(): void
     public function invalidMovePaths(): array
     {
         return [
-            'null'   => [null],
-            'true'   => [true],
-            'false'  => [false],
-            'int'    => [1],
-            'float'  => [1.1],
             'empty'  => [''],
-            'array'  => [['filename']],
-            'object' => [(object) ['filename']],
         ];
     }
 
diff --git a/tests/UriTest.php b/tests/UriTest.php
index 195933a..3a44278 100644
--- a/tests/UriTest.php
+++ b/tests/UriTest.php
@@ -137,62 +137,6 @@ public function testParseUriPortCannotBeZero(): void
         new Uri('//example.com:-1');
     }
 
-    public function testSchemeMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Scheme must be a string');
-
-        (new Uri())->withScheme([]);
-    }
-
-    public function testUserInfoUserMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('User must be a string');
-
-        (new Uri())->withUserInfo([]);
-    }
-
-    public function testUserInfoPasswordMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Password must be a string or NULL');
-
-        (new Uri())->withUserInfo('', []);
-    }
-
-    public function testHostMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Host must be a string');
-
-        (new Uri())->withHost([]);
-    }
-
-    public function testPathMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Path must be a string');
-
-        (new Uri())->withPath([]);
-    }
-
-    public function testQueryMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Query and fragment must be a string');
-
-        (new Uri())->withQuery([]);
-    }
-
-    public function testFragmentMustHaveCorrectType(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-        $this->expectExceptionMessage('Query and fragment must be a string');
-
-        (new Uri())->withFragment([]);
-    }
-
     public function testCanParseFalseyUriParts(): void
     {
         $uri = new Uri('0://0:0@0/0?0#0');
@@ -353,14 +297,6 @@ public function testStandardPortIsNullIfSchemeChanges(): void
         static::assertNull($uri->getPort());
     }
 
-    public function testPortPassedAsStringIsCastedToInt(): void
-    {
-        $uri = (new Uri('//example.com'))->withPort('8080');
-
-        static::assertSame(8080, $uri->getPort(), 'Port is returned as integer');
-        static::assertSame('example.com:8080', $uri->getAuthority());
-    }
-
     public function testPortCanBeRemoved(): void
     {
         $uri = (new Uri('http://example.com:8080'))->withPort(null);