diff --git a/src/Format/Format.php b/src/Format/Format.php
index 6250b1fb..da089d2b 100644
--- a/src/Format/Format.php
+++ b/src/Format/Format.php
@@ -15,6 +15,11 @@
 
 final class Format implements FormatInterface
 {
+    /**
+     * Constant for a regular expression matching valid indents.
+     */
+    private const INDENT_PATTERN = '/^[ \t]+$/';
+
     /**
      * @var int
      */
@@ -46,7 +51,7 @@ public function __construct(int $jsonEncodeOptions, string $indent, bool $hasFin
             ));
         }
 
-        if (1 !== \preg_match('/^[ \t]+$/', $indent)) {
+        if (1 !== \preg_match(self::INDENT_PATTERN, $indent)) {
             throw new \InvalidArgumentException(\sprintf(
                 '"%s" is not a valid indent.',
                 $indent
@@ -72,4 +77,45 @@ public function hasFinalNewLine(): bool
     {
         return $this->hasFinalNewLine;
     }
+
+    public function withJsonEncodeOptions(int $jsonEncodeOptions): FormatInterface
+    {
+        if (0 > $jsonEncodeOptions) {
+            throw new \InvalidArgumentException(\sprintf(
+                '"%s" is not valid options for json_encode().',
+                $jsonEncodeOptions
+            ));
+        }
+
+        $mutated = clone $this;
+
+        $mutated->jsonEncodeOptions = $jsonEncodeOptions;
+
+        return $mutated;
+    }
+
+    public function withIndent(string $indent): FormatInterface
+    {
+        if (1 !== \preg_match(self::INDENT_PATTERN, $indent)) {
+            throw new \InvalidArgumentException(\sprintf(
+                '"%s" is not a valid indent.',
+                $indent
+            ));
+        }
+
+        $mutated = clone $this;
+
+        $mutated->indent = $indent;
+
+        return $mutated;
+    }
+
+    public function withHasFinalNewLine(bool $hasFinalNewLine): FormatInterface
+    {
+        $mutated = clone $this;
+
+        $mutated->hasFinalNewLine = $hasFinalNewLine;
+
+        return $mutated;
+    }
 }
diff --git a/src/Format/FormatInterface.php b/src/Format/FormatInterface.php
index 3351fefc..0815074a 100644
--- a/src/Format/FormatInterface.php
+++ b/src/Format/FormatInterface.php
@@ -20,4 +20,24 @@ public function jsonEncodeOptions(): int;
     public function indent(): string;
 
     public function hasFinalNewLine(): bool;
+
+    /**
+     * @param string $indent
+     *
+     * @throws \InvalidArgumentException
+     *
+     * @return FormatInterface
+     */
+    public function withIndent(string $indent): self;
+
+    /**
+     * @param int $jsonEncodeOptions
+     *
+     * @throws \InvalidArgumentException
+     *
+     * @return FormatInterface
+     */
+    public function withJsonEncodeOptions(int $jsonEncodeOptions): self;
+
+    public function withHasFinalNewLine(bool $hasFinalNewLine): self;
 }
diff --git a/test/Unit/Format/FormatTest.php b/test/Unit/Format/FormatTest.php
index a5f18a86..43ce79be 100644
--- a/test/Unit/Format/FormatTest.php
+++ b/test/Unit/Format/FormatTest.php
@@ -106,18 +106,8 @@ public function testConstructorSetsValues(string $indent, bool $hasFinalNewLine)
 
     public function providerJsonIndentAndFinalNewLine(): \Generator
     {
-        $indents = [
-            '  ',
-            "\t",
-        ];
-
-        $hasFinalNewLines = [
-            true,
-            false,
-        ];
-
-        foreach ($indents as $indent) {
-            foreach ($hasFinalNewLines as $hasFinalNewLine) {
+        foreach ($this->indents() as $indent) {
+            foreach ($this->hasFinalNewLines() as $hasFinalNewLine) {
                 yield [
                     $indent,
                     $hasFinalNewLine,
@@ -125,4 +115,142 @@ public function providerJsonIndentAndFinalNewLine(): \Generator
             }
         }
     }
+
+    public function testWithJsonEncodeOptionsRejectsInvalidJsonEncodeOptions(): void
+    {
+        $jsonEncodeOptions = -1;
+
+        $format = new Format(
+            JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES,
+            '    ',
+            true
+        );
+
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage(\sprintf(
+            '"%s" is not valid options for json_encode().',
+            $jsonEncodeOptions
+        ));
+
+        $format->withJsonEncodeOptions($jsonEncodeOptions);
+    }
+
+    public function testWithIndentClonesFormatAndSetsJsonEncodeOptions(): void
+    {
+        $format = new Format(
+            JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES,
+            '    ',
+            true
+        );
+
+        $jsonEncodeOptions = 9000;
+
+        $mutated = $format->withJsonEncodeOptions($jsonEncodeOptions);
+
+        $this->assertInstanceOf(FormatInterface::class, $mutated);
+        $this->assertNotSame($format, $mutated);
+        $this->assertSame($jsonEncodeOptions, $mutated->jsonEncodeOptions());
+    }
+
+    /**
+     * @dataProvider providerInvalidIndent
+     *
+     * @param string $indent
+     */
+    public function testWithIndentRejectsInvalidIndent(string $indent): void
+    {
+        $format = new Format(
+            JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES,
+            '    ',
+            true
+        );
+
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage(\sprintf(
+            '"%s" is not a valid indent.',
+            $indent
+        ));
+
+        $format->withIndent($indent);
+    }
+
+    /**
+     * @dataProvider providerIndent
+     *
+     * @param string $indent
+     */
+    public function testWithIndentClonesFormatAndSetsIndent(string $indent): void
+    {
+        $format = new Format(
+            JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES,
+            '    ',
+            true
+        );
+
+        $mutated = $format->withIndent($indent);
+
+        $this->assertInstanceOf(FormatInterface::class, $mutated);
+        $this->assertNotSame($format, $mutated);
+        $this->assertSame($indent, $mutated->indent());
+    }
+
+    public function providerIndent(): \Generator
+    {
+        foreach ($this->indents() as $key => $indent) {
+            yield $key => [
+                $indent,
+            ];
+        }
+    }
+
+    /**
+     * @dataProvider providerHasFinalNewLine
+     *
+     * @param bool $hasFinalNewLine
+     */
+    public function testWithHasFinalNewLineClonesFormatAndSetsFinalNewLine(bool $hasFinalNewLine): void
+    {
+        $format = new Format(
+            JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES,
+            '    ',
+            false
+        );
+
+        $mutated = $format->withHasFinalNewLine($hasFinalNewLine);
+
+        $this->assertInstanceOf(FormatInterface::class, $mutated);
+        $this->assertNotSame($format, $mutated);
+        $this->assertSame($hasFinalNewLine, $mutated->hasFinalNewLine());
+    }
+
+    public function providerHasFinalNewLine(): \Generator
+    {
+        foreach ($this->hasFinalNewLines() as $key => $hasFinalNewLine) {
+            yield $key => [
+                $hasFinalNewLine,
+            ];
+        }
+    }
+
+    /**
+     * @return string[]
+     */
+    private function indents(): array
+    {
+        return [
+            'space' => '  ',
+            'tab' => "\t",
+        ];
+    }
+
+    /**
+     * @return bool[]
+     */
+    private function hasFinalNewLines(): array
+    {
+        return [
+            'yes' => true,
+            'no' => false,
+        ];
+    }
 }