diff --git a/src/Contracts/SignatureGenerator.php b/src/Contracts/SignatureGenerator.php
new file mode 100644
index 0000000..7f43a2b
--- /dev/null
+++ b/src/Contracts/SignatureGenerator.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Naoray\LaravelGithubMonolog\Contracts;
+
+use Monolog\LogRecord;
+
+interface SignatureGenerator
+{
+    /**
+     * Generate a unique signature for the log record
+     */
+    public function generate(LogRecord $record): string;
+}
diff --git a/src/DefaultSignatureGenerator.php b/src/DefaultSignatureGenerator.php
new file mode 100644
index 0000000..acc0939
--- /dev/null
+++ b/src/DefaultSignatureGenerator.php
@@ -0,0 +1,48 @@
+<?php
+
+namespace Naoray\LaravelGithubMonolog;
+
+use Monolog\LogRecord;
+use Naoray\LaravelGithubMonolog\Contracts\SignatureGenerator;
+use Throwable;
+
+class DefaultSignatureGenerator implements SignatureGenerator
+{
+    /**
+     * Generate a unique signature for the log record
+     */
+    public function generate(LogRecord $record): string
+    {
+        $exception = $record->context['exception'] ?? null;
+
+        if (!$exception instanceof Throwable) {
+            return $this->generateFromMessage($record);
+        }
+
+        return $this->generateFromException($exception);
+    }
+
+    /**
+     * Generate a signature from a message and context
+     */
+    private function generateFromMessage(LogRecord $record): string
+    {
+        return md5($record->message . json_encode($record->context));
+    }
+
+    /**
+     * Generate a signature from an exception
+     */
+    private function generateFromException(Throwable $exception): string
+    {
+        $trace = $exception->getTrace();
+        $firstFrame = !empty($trace) ? $trace[0] : null;
+
+        return md5(implode(':', [
+            $exception::class,
+            $exception->getFile(),
+            $exception->getLine(),
+            $firstFrame ? ($firstFrame['file'] ?? '') . ':' . ($firstFrame['line'] ?? '') : '',
+        ]));
+    }
+}
diff --git a/src/GithubIssueFormatted.php b/src/Formatters/GithubIssueFormatted.php
similarity index 82%
rename from src/GithubIssueFormatted.php
rename to src/Formatters/GithubIssueFormatted.php
index 286aeb3..3b4d6c1 100644
--- a/src/GithubIssueFormatted.php
+++ b/src/Formatters/GithubIssueFormatted.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Naoray\LaravelGithubMonolog;
+namespace Naoray\LaravelGithubMonolog\Formatters;
 
 class GithubIssueFormatted
 {
diff --git a/src/GithubIssueFormatter.php b/src/Formatters/GithubIssueFormatter.php
similarity index 91%
rename from src/GithubIssueFormatter.php
rename to src/Formatters/GithubIssueFormatter.php
index 9facc9d..1f5827f 100644
--- a/src/GithubIssueFormatter.php
+++ b/src/Formatters/GithubIssueFormatter.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Naoray\LaravelGithubMonolog;
+namespace Naoray\LaravelGithubMonolog\Formatters;
 
 use Illuminate\Support\Collection;
 use Illuminate\Support\Str;
@@ -54,7 +54,7 @@ public function formatBatch(array $records): array
     private function generateSignature(LogRecord $record, ?Throwable $exception): string
     {
         if (! $exception) {
-            return md5($record->message.json_encode($record->context));
+            return md5($record->message . json_encode($record->context));
         }
 
         $trace = $exception->getTrace();
@@ -64,7 +64,7 @@ private function generateSignature(LogRecord $record, ?Throwable $exception): st
             $exception::class,
             $exception->getFile(),
             $exception->getLine(),
-            $firstFrame ? ($firstFrame['file'] ?? '').':'.($firstFrame['line'] ?? '') : '',
+            $firstFrame ? ($firstFrame['file'] ?? '') . ':' . ($firstFrame['line'] ?? '') : '',
         ]));
     }
 
@@ -110,7 +110,7 @@ private function formatTitle(LogRecord $record, ?Throwable $exception = null): s
     private function formatContent(LogRecord $record, ?Throwable $exception): string
     {
         return Str::of('')
-            ->when($record->message, fn ($str, $message) => $str->append("**Message:**\n{$message}\n\n"))
+            ->when($record->message, fn($str, $message) => $str->append("**Message:**\n{$message}\n\n"))
             ->when(
                 $exception,
                 function (Stringable $str, Throwable $exception) {
@@ -120,8 +120,8 @@ function (Stringable $str, Throwable $exception) {
                     );
                 }
             )
-            ->when(! $exception && ! empty($record->context), fn ($str, $context) => $str->append("**Context:**\n```json\n".json_encode($record->context, JSON_PRETTY_PRINT)."\n```\n\n"))
-            ->when(! empty($record->extra), fn ($str, $extra) => $str->append("**Extra Data:**\n```json\n".json_encode($record->extra, JSON_PRETTY_PRINT)."\n```\n"))
+            ->when(! $exception && ! empty($record->context), fn($str, $context) => $str->append("**Context:**\n```json\n" . json_encode($record->context, JSON_PRETTY_PRINT) . "\n```\n\n"))
+            ->when(! empty($record->extra), fn($str, $extra) => $str->append("**Extra Data:**\n```json\n" . json_encode($record->extra, JSON_PRETTY_PRINT) . "\n```\n"))
             ->toString();
     }
 
@@ -141,7 +141,7 @@ private function formatBody(LogRecord $record, string $signature, ?Throwable $ex
     private function cleanStackTrace(string $stackTrace): string
     {
         return collect(explode("\n", $stackTrace))
-            ->filter(fn ($line) => ! empty(trim($line)))
+            ->filter(fn($line) => ! empty(trim($line)))
             ->map(function ($line) {
                 if (trim($line) === '"}') {
                     return '';
@@ -217,8 +217,8 @@ private function formatExceptionDetails(Throwable $exception): array
 
         return [
             'message' => $exception->getMessage(),
-            'stack_trace' => $header."\n[stacktrace]\n".$this->cleanStackTrace($exception->getTraceAsString()),
-            'full_stack_trace' => $header."\n[stacktrace]\n".$exception->getTraceAsString(),
+            'stack_trace' => $header . "\n[stacktrace]\n" . $this->cleanStackTrace($exception->getTraceAsString()),
+            'full_stack_trace' => $header . "\n[stacktrace]\n" . $exception->getTraceAsString(),
         ];
     }
 
diff --git a/src/GithubIssueHandlerFactory.php b/src/GithubIssueHandlerFactory.php
index 4a47c9a..149e025 100644
--- a/src/GithubIssueHandlerFactory.php
+++ b/src/GithubIssueHandlerFactory.php
@@ -5,9 +5,11 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Facades\File;
 use InvalidArgumentException;
-use Monolog\Handler\DeduplicationHandler;
 use Monolog\Level;
 use Monolog\Logger;
+use Naoray\LaravelGithubMonolog\Formatters\GithubIssueFormatter;
+use Naoray\LaravelGithubMonolog\Handlers\SignatureDeduplicationHandler;
+use Naoray\LaravelGithubMonolog\Handlers\IssueLogHandler;
 
 class GithubIssueHandlerFactory
 {
@@ -32,9 +34,9 @@ protected function validateConfig(array $config): void
         }
     }
 
-    protected function createBaseHandler(array $config): GithubIssueLoggerHandler
+    protected function createBaseHandler(array $config): IssueLogHandler
     {
-        $handler = new GithubIssueLoggerHandler(
+        $handler = new IssueLogHandler(
             repo: $config['repo'],
             token: $config['token'],
             labels: $config['labels'] ?? [],
@@ -47,9 +49,9 @@ protected function createBaseHandler(array $config): GithubIssueLoggerHandler
         return $handler;
     }
 
-    protected function wrapWithDeduplication(GithubIssueLoggerHandler $handler, array $config): DeduplicationHandler
+    protected function wrapWithDeduplication(IssueLogHandler $handler, array $config): SignatureDeduplicationHandler
     {
-        return new DeduplicationHandler(
+        return new SignatureDeduplicationHandler(
             $handler,
             deduplicationStore: $this->getDeduplicationStore($config),
             deduplicationLevel: Arr::get($config, 'level', Level::Error),
diff --git a/src/GithubIssueLoggerHandler.php b/src/Handlers/IssueLogHandler.php
similarity index 90%
rename from src/GithubIssueLoggerHandler.php
rename to src/Handlers/IssueLogHandler.php
index 7b5a5fe..5687ec3 100644
--- a/src/GithubIssueLoggerHandler.php
+++ b/src/Handlers/IssueLogHandler.php
@@ -1,20 +1,18 @@
 <?php
 
-namespace Naoray\LaravelGithubMonolog;
+namespace Naoray\LaravelGithubMonolog\Handlers;
 
 use Illuminate\Support\Facades\Http;
 use Monolog\Handler\AbstractProcessingHandler;
 use Monolog\Level;
 use Monolog\LogRecord;
+use Naoray\LaravelGithubMonolog\Formatters\GithubIssueFormatted;
 
-class GithubIssueLoggerHandler extends AbstractProcessingHandler
+class IssueLogHandler extends AbstractProcessingHandler
 {
     private string $repo;
-
     private string $token;
-
     private array $labels;
-
     private const DEFAULT_LABEL = 'github-issue-logger';
 
     /**
@@ -66,11 +64,11 @@ private function findExistingIssue(string $signature): ?array
     {
         $response = Http::withToken($this->token)
             ->get('https://api.github.com/search/issues', [
-                'q' => "repo:{$this->repo} is:issue is:open label:".self::DEFAULT_LABEL." \"Signature: {$signature}\"",
+                'q' => "repo:{$this->repo} is:issue is:open label:" . self::DEFAULT_LABEL . " \"Signature: {$signature}\"",
             ]);
 
         if ($response->failed()) {
-            throw new \RuntimeException('Failed to search GitHub issues: '.$response->body());
+            throw new \RuntimeException('Failed to search GitHub issues: ' . $response->body());
         }
 
         return $response->json('items.0', null);
@@ -87,7 +85,7 @@ private function commentOnIssue(int $issueNumber, GithubIssueFormatted $formatte
             ]);
 
         if ($response->failed()) {
-            throw new \RuntimeException('Failed to comment on GitHub issue: '.$response->body());
+            throw new \RuntimeException('Failed to comment on GitHub issue: ' . $response->body());
         }
     }
 
@@ -104,7 +102,7 @@ private function createIssue(GithubIssueFormatted $formatted): void
             ]);
 
         if ($response->failed()) {
-            throw new \RuntimeException('Failed to create GitHub issue: '.$response->body());
+            throw new \RuntimeException('Failed to create GitHub issue: ' . $response->body());
         }
     }
 }
diff --git a/src/Handlers/SignatureDeduplicationHandler.php b/src/Handlers/SignatureDeduplicationHandler.php
new file mode 100644
index 0000000..1cea8e0
--- /dev/null
+++ b/src/Handlers/SignatureDeduplicationHandler.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace Naoray\LaravelGithubMonolog\Handlers;
+
+use Monolog\Handler\DeduplicationHandler;
+use Monolog\Handler\HandlerInterface;
+use Monolog\Level;
+use Monolog\LogRecord;
+use Naoray\LaravelGithubMonolog\Contracts\SignatureGenerator;
+use Naoray\LaravelGithubMonolog\DefaultSignatureGenerator;
+
+class SignatureDeduplicationHandler extends DeduplicationHandler
+{
+    private SignatureGenerator $signatureGenerator;
+
+    public function __construct(
+        HandlerInterface $handler,
+        ?string $deduplicationStore = null,
+        int|string|Level $deduplicationLevel = Level::Error,
+        int $time = 60,
+        bool $bubble = true,
+        ?SignatureGenerator $signatureGenerator = null,
+    ) {
+        parent::__construct($handler, $deduplicationStore, $deduplicationLevel, $time, $bubble);
+        $this->signatureGenerator = $signatureGenerator ?? new DefaultSignatureGenerator();
+    }
+
+    /**
+     * Override isDuplicate to use our signature-based deduplication
+     */
+    protected function isDuplicate(array $store, LogRecord $record): bool
+    {
+        $timestampValidity = $record->datetime->getTimestamp() - $this->time;
+        $signature = $this->signatureGenerator->generate($record);
+
+        foreach ($store as $entry) {
+            [$timestamp, $storedSignature] = explode(':', $entry, 2);
+
+            if ($storedSignature === $signature && $timestamp > $timestampValidity) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Override store entry format to use our signature
+     */
+    protected function buildDeduplicationStoreEntry(LogRecord $record): string
+    {
+        return $record->datetime->getTimestamp() . ':' . $this->signatureGenerator->generate($record);
+    }
+}
diff --git a/tests/DefaultSignatureGeneratorTest.php b/tests/DefaultSignatureGeneratorTest.php
new file mode 100644
index 0000000..1f9851c
--- /dev/null
+++ b/tests/DefaultSignatureGeneratorTest.php
@@ -0,0 +1,87 @@
+<?php
+
+use Monolog\Level;
+use Monolog\LogRecord;
+use Naoray\LaravelGithubMonolog\DefaultSignatureGenerator;
+
+beforeEach(function () {
+    $this->generator = new DefaultSignatureGenerator();
+});
+
+test('generates signature from message', function () {
+    $record = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'test',
+        level: Level::Error,
+        message: 'Test message',
+        context: ['foo' => 'bar'],
+        extra: [],
+    );
+
+    $signature1 = $this->generator->generate($record);
+    expect($signature1)->toBeString();
+
+    // Same message and context should generate same signature
+    $record2 = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'different-channel',
+        level: Level::Warning,
+        message: 'Test message',
+        context: ['foo' => 'bar'],
+        extra: ['something' => 'else'],
+    );
+    $signature2 = $this->generator->generate($record2);
+    expect($signature2)->toBe($signature1);
+
+    // Different message should generate different signature
+    $record3 = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'test',
+        level: Level::Error,
+        message: 'Different message',
+        context: ['foo' => 'bar'],
+        extra: [],
+    );
+    $signature3 = $this->generator->generate($record3);
+    expect($signature3)->not->toBe($signature1);
+});
+
+test('generates signature from exception', function () {
+    $exception = new \Exception('Test exception');
+    $record = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'test',
+        level: Level::Error,
+        message: 'Test message',
+        context: ['exception' => $exception],
+        extra: [],
+    );
+
+    $signature1 = $this->generator->generate($record);
+    expect($signature1)->toBeString();
+
+    // Same exception should generate same signature
+    $record2 = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'different-channel',
+        level: Level::Warning,
+        message: 'Different message',
+        context: ['exception' => $exception],
+        extra: ['something' => 'else'],
+    );
+    $signature2 = $this->generator->generate($record2);
+    expect($signature2)->toBe($signature1);
+
+    // Different exception should generate different signature
+    $differentException = new \Exception('Different exception');
+    $record3 = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'test',
+        level: Level::Error,
+        message: 'Test message',
+        context: ['exception' => $differentException],
+        extra: [],
+    );
+    $signature3 = $this->generator->generate($record3);
+    expect($signature3)->not->toBe($signature1);
+});
diff --git a/tests/GithubIssueFormatterTest.php b/tests/Formatters/GithubIssueFormatterTest.php
similarity index 97%
rename from tests/GithubIssueFormatterTest.php
rename to tests/Formatters/GithubIssueFormatterTest.php
index 45c0a6b..e9b7483 100644
--- a/tests/GithubIssueFormatterTest.php
+++ b/tests/Formatters/GithubIssueFormatterTest.php
@@ -2,8 +2,8 @@
 
 use Monolog\Level;
 use Monolog\LogRecord;
-use Naoray\LaravelGithubMonolog\GithubIssueFormatted;
-use Naoray\LaravelGithubMonolog\GithubIssueFormatter;
+use Naoray\LaravelGithubMonolog\Formatters\GithubIssueFormatted;
+use Naoray\LaravelGithubMonolog\Formatters\GithubIssueFormatter;
 
 test('it formats basic log records', function () {
     $formatter = new GithubIssueFormatter;
diff --git a/tests/GithubIssueHandlerFactoryTest.php b/tests/GithubIssueHandlerFactoryTest.php
index 2dc4679..3e5fbb6 100644
--- a/tests/GithubIssueHandlerFactoryTest.php
+++ b/tests/GithubIssueHandlerFactoryTest.php
@@ -3,12 +3,11 @@
 use Monolog\Handler\DeduplicationHandler;
 use Monolog\Level;
 use Monolog\Logger;
-use Naoray\LaravelGithubMonolog\GithubIssueFormatter;
+use Naoray\LaravelGithubMonolog\Formatters\GithubIssueFormatter;
 use Naoray\LaravelGithubMonolog\GithubIssueHandlerFactory;
-use Naoray\LaravelGithubMonolog\GithubIssueLoggerHandler;
-use ReflectionProperty;
+use Naoray\LaravelGithubMonolog\Handlers\IssueLogHandler;
 
-function getWrappedHandler(DeduplicationHandler $handler): GithubIssueLoggerHandler
+function getWrappedHandler(DeduplicationHandler $handler): IssueLogHandler
 {
     $reflection = new ReflectionProperty($handler, 'handler');
     $reflection->setAccessible(true);
@@ -45,16 +44,16 @@ function getDeduplicationStore(DeduplicationHandler $handler): string
     $deduplicationHandler = $logger->getHandlers()[0];
     $handler = getWrappedHandler($deduplicationHandler);
 
-    expect($handler)->toBeInstanceOf(GithubIssueLoggerHandler::class);
+    expect($handler)->toBeInstanceOf(IssueLogHandler::class);
 });
 
 test('it throws exception for missing required config', function () {
     $factory = new GithubIssueHandlerFactory;
 
-    expect(fn () => $factory([]))
+    expect(fn() => $factory([]))
         ->toThrow(InvalidArgumentException::class, 'GitHub repository is required');
 
-    expect(fn () => $factory(['repo' => 'test/repo']))
+    expect(fn() => $factory(['repo' => 'test/repo']))
         ->toThrow(InvalidArgumentException::class, 'GitHub token is required');
 });
 
@@ -72,7 +71,7 @@ function getDeduplicationStore(DeduplicationHandler $handler): string
     $handler = getWrappedHandler($deduplicationHandler);
 
     expect($handler)
-        ->toBeInstanceOf(GithubIssueLoggerHandler::class)
+        ->toBeInstanceOf(IssueLogHandler::class)
         ->and($handler->getLevel())->toBe(Level::Error)
         ->and($handler->getBubble())->toBeTrue()
         ->and($handler->getFormatter())->toBeInstanceOf(GithubIssueFormatter::class);
diff --git a/tests/GithubIssueLoggerHandlerTest.php b/tests/Handlers/IssueLogHandlerTest.php
similarity index 94%
rename from tests/GithubIssueLoggerHandlerTest.php
rename to tests/Handlers/IssueLogHandlerTest.php
index d195bc5..114e576 100644
--- a/tests/GithubIssueLoggerHandlerTest.php
+++ b/tests/Handlers/IssueLogHandlerTest.php
@@ -4,11 +4,11 @@
 use Illuminate\Support\Facades\Http;
 use Monolog\Level;
 use Monolog\LogRecord;
-use Naoray\LaravelGithubMonolog\GithubIssueFormatter;
-use Naoray\LaravelGithubMonolog\GithubIssueLoggerHandler;
+use Naoray\LaravelGithubMonolog\Formatters\GithubIssueFormatter;
+use Naoray\LaravelGithubMonolog\Handlers\IssueLogHandler;
 
 beforeEach(function () {
-    $this->handler = (new GithubIssueLoggerHandler(
+    $this->handler = (new IssueLogHandler(
         repo: 'test/repo',
         token: 'fake-token',
         labels: ['bug'],
@@ -28,7 +28,7 @@ function createLogRecord(string $message = 'Test error', array $context = [], Le
     );
 }
 
-function createFormattedRecord(GithubIssueLoggerHandler $handler, string $message = 'Test error', array $context = [], Level $level = Level::Error): LogRecord
+function createFormattedRecord(IssueLogHandler $handler, string $message = 'Test error', array $context = [], Level $level = Level::Error): LogRecord
 {
     $baseRecord = createLogRecord($message, $context, $level);
 
@@ -81,7 +81,7 @@ function createFormattedRecord(GithubIssueLoggerHandler $handler, string $messag
         'github.com/search/issues*' => Http::response(['message' => 'Bad credentials'], 401),
     ]);
 
-    expect(fn () => $this->handler->handle(createFormattedRecord($this->handler)))
+    expect(fn() => $this->handler->handle(createFormattedRecord($this->handler)))
         ->toThrow(\RuntimeException::class, 'Failed to search GitHub issues');
 });
 
@@ -91,7 +91,7 @@ function createFormattedRecord(GithubIssueLoggerHandler $handler, string $messag
         'github.com/repos/test/repo/issues' => Http::response(['number' => 1], 201),
     ]);
 
-    $handler = (new GithubIssueLoggerHandler(
+    $handler = (new IssueLogHandler(
         repo: 'test/repo',
         token: 'fake-token',
         labels: ['custom-label', 'another-label'],
@@ -214,7 +214,7 @@ function createFormattedRecord(GithubIssueLoggerHandler $handler, string $messag
 
     $record = createFormattedRecord($this->handler);
 
-    expect(fn () => $this->handler->handle($record))
+    expect(fn() => $this->handler->handle($record))
         ->toThrow(\RuntimeException::class, 'Failed to create GitHub issue');
 });
 
diff --git a/tests/Handlers/SignatureDeduplicationHandlerTest.php b/tests/Handlers/SignatureDeduplicationHandlerTest.php
new file mode 100644
index 0000000..be0ae6a
--- /dev/null
+++ b/tests/Handlers/SignatureDeduplicationHandlerTest.php
@@ -0,0 +1,109 @@
+<?php
+
+use Monolog\Handler\NullHandler;
+use Monolog\Level;
+use Monolog\LogRecord;
+use Naoray\LaravelGithubMonolog\DefaultSignatureGenerator;
+use Naoray\LaravelGithubMonolog\Handlers\SignatureDeduplicationHandler;
+
+beforeEach(function () {
+    $this->deduplicationStore = sys_get_temp_dir() . '/test-dedup-' . uniqid() . '.log';
+    $this->signatureGenerator = new DefaultSignatureGenerator();
+    $this->handler = new SignatureDeduplicationHandler(
+        new NullHandler(),
+        $this->deduplicationStore,
+        Level::Debug,
+        time: 60,
+        signatureGenerator: $this->signatureGenerator
+    );
+});
+
+afterEach(function () {
+    if (file_exists($this->deduplicationStore)) {
+        unlink($this->deduplicationStore);
+    }
+});
+
+test('deduplicates records with same signature', function () {
+    $record1 = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'test',
+        level: Level::Error,
+        message: 'Test message',
+        context: ['foo' => 'bar'],
+        extra: [],
+    );
+
+    // First record should be handled
+    $this->handler->handle($record1);
+    $this->handler->flush();
+    expect(file_exists($this->deduplicationStore))->toBeTrue();
+
+    // Same signature should be deduplicated
+    $record2 = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'different-channel',
+        level: Level::Error,
+        message: 'Test message',
+        context: ['foo' => 'bar'],
+        extra: ['something' => 'else'],
+    );
+    $this->handler->handle($record2);
+    $this->handler->flush();
+
+    // Different signature should not be deduplicated
+    $record3 = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'test',
+        level: Level::Error,
+        message: 'Different message',
+        context: ['foo' => 'bar'],
+        extra: [],
+    );
+    $this->handler->handle($record3);
+
+    // Verify deduplication store contains both unique signatures
+    $this->handler->close();
+    $contents = file_get_contents($this->deduplicationStore);
+    expect($contents)
+        ->toContain($this->signatureGenerator->generate($record1))
+        ->toContain($this->signatureGenerator->generate($record3));
+});
+
+test('deduplication respects time window', function () {
+    $record = new LogRecord(
+        datetime: new \DateTimeImmutable(),
+        channel: 'test',
+        level: Level::Error,
+        message: 'Test message',
+        context: ['foo' => 'bar'],
+        extra: [],
+    );
+
+    // Create handler with 1 second time window
+    $handler = new SignatureDeduplicationHandler(
+        new NullHandler(),
+        $this->deduplicationStore,
+        Level::Debug,
+        time: 1,
+        signatureGenerator: $this->signatureGenerator
+    );
+
+    // First record should be handled
+    $handler->handle($record);
+    $handler->flush();
+    expect(file_exists($this->deduplicationStore))->toBeTrue();
+
+    // Wait for time window to expire
+    sleep(2);
+
+    // Same record should be handled again after time window
+    $handler->handle($record);
+    $handler->flush();
+    $handler->close();
+
+    // Verify deduplication store contains only the most recent entry
+    $contents = file_get_contents($this->deduplicationStore);
+    $signature = $this->signatureGenerator->generate($record);
+    expect(substr_count($contents, $signature))->toBe(1);
+});