diff --git a/src/Model.php b/src/Model.php
index 65dc938b..5ce9ef6a 100644
--- a/src/Model.php
+++ b/src/Model.php
@@ -14,6 +14,7 @@
 use DirectoryTree\ActiveRedis\Exceptions\DuplicateKeyException;
 use DirectoryTree\ActiveRedis\Exceptions\InvalidKeyException;
 use DirectoryTree\ActiveRedis\Exceptions\JsonEncodingException;
+use DirectoryTree\ActiveRedis\Repositories\ArrayRepository;
 use DirectoryTree\ActiveRedis\Repositories\RedisRepository;
 use DirectoryTree\ActiveRedis\Repositories\Repository;
 use Illuminate\Contracts\Redis\Connection;
@@ -26,6 +27,7 @@
 use Illuminate\Support\Facades\Date;
 use Illuminate\Support\Str;
 use Illuminate\Support\Traits\ForwardsCalls;
+use InvalidArgumentException;
 use JsonException;
 use Stringable;
 
@@ -84,6 +86,11 @@ abstract class Model implements Arrayable, ArrayAccess, Jsonable, Stringable, Ur
      */
     protected ?string $connection = null;
 
+    /**
+     * The repository for the model.
+     */
+    protected static string $repository = 'redis';
+
     /**
      * Handle dynamic method calls into the model.
      */
@@ -411,12 +418,24 @@ public function newBuilder(): Query
         return new Query($this, $this->newRepository());
     }
 
+    /**
+     * Set the repository for the model.
+     */
+    public static function setRepository(string $repository): void
+    {
+        static::$repository = $repository;
+    }
+
     /**
      * Create a new repository instance.
      */
     protected function newRepository(): Repository
     {
-        return new RedisRepository($this->getConnection());
+        return match ($repository = static::$repository) {
+            'array' => new ArrayRepository,
+            'redis' => new RedisRepository($this->getConnection()),
+            default => throw new InvalidArgumentException("Repository [{$repository}] is not supported."),
+        };
     }
 
     /**
diff --git a/src/Repositories/ArrayRepository.php b/src/Repositories/ArrayRepository.php
new file mode 100644
index 00000000..0d036568
--- /dev/null
+++ b/src/Repositories/ArrayRepository.php
@@ -0,0 +1,148 @@
+<?php
+
+namespace DirectoryTree\ActiveRedis\Repositories;
+
+use Closure;
+use Generator;
+use Illuminate\Support\Str;
+
+class ArrayRepository implements Repository
+{
+    /**
+     * Constructor.
+     */
+    public function __construct(
+        protected array $data = [],
+        protected array $expiry = [],
+    ) {}
+
+    /**
+     * Determine if the given hash exists.
+     */
+    public function exists(string $hash): bool
+    {
+        return isset($this->data[$hash]);
+    }
+
+    /**
+     * Chunk through the hashes matching the given pattern.
+     */
+    public function chunk(string $pattern, int $count): Generator
+    {
+        $matches = [];
+
+        foreach (array_keys($this->data) as $key) {
+            if (Str::is($pattern, $key)) {
+                $matches[] = $key;
+            }
+        }
+
+        foreach (array_chunk($matches, $count) as $chunk) {
+            yield $chunk;
+        }
+    }
+
+    /**
+     * Set the hash field's value.
+     */
+    public function setAttribute(string $hash, string $attribute, string $value): void
+    {
+        $this->data[$hash][$attribute] = $value;
+    }
+
+    /**
+     * Set the hash field's value.
+     */
+    public function setAttributes(string $hash, array $attributes): void
+    {
+        foreach ($attributes as $attribute => $value) {
+            $this->setAttribute($hash, $attribute, $value);
+        }
+    }
+
+    /**
+     * Get the hash field's value.
+     */
+    public function getAttribute(string $hash, string $field): mixed
+    {
+        if ($this->isExpired($hash)) {
+            $this->delete($hash);
+
+            return null;
+        }
+
+        return $this->data[$hash][$field] ?? null;
+    }
+
+    /**
+     * Get all the attributes in the hash.
+     */
+    public function getAttributes(string $hash): array
+    {
+        if ($this->isExpired($hash)) {
+            $this->delete($hash);
+
+            return [];
+        }
+
+        return $this->data[$hash] ?? [];
+    }
+
+    /**
+     * Set a time-to-live on a hash key.
+     *
+     * Not supported in ArrayRepository.
+     */
+    public function setExpiry(string $hash, int $seconds): void
+    {
+        $this->expiry[$hash] = time() + $seconds;
+    }
+
+    /**
+     * Get the time-to-live of a hash key.
+     */
+    public function getExpiry(string $hash): ?int
+    {
+        if (! isset($this->expiry[$hash])) {
+            return null;
+        }
+
+        $remaining = $this->expiry[$hash] - time();
+
+        return $remaining > 0 ? $remaining : null;
+    }
+
+    /**
+     * Delete the attributes from the hash.
+     */
+    public function deleteAttributes(string $hash, array|string $attributes): void
+    {
+        foreach ((array) $attributes as $attribute) {
+            unset($this->data[$hash][$attribute]);
+        }
+    }
+
+    /**
+     * Delete the given hash.
+     */
+    public function delete(string $hash): void
+    {
+        unset($this->data[$hash]);
+    }
+
+    /**
+     * Perform a transaction.
+     */
+    public function transaction(Closure $operation): void
+    {
+        $operation($this);
+    }
+
+    /**
+     * Determine if the given hash has expired.
+     */
+    protected function isExpired(string $hash): bool
+    {
+        return isset($this->expiry[$hash]) && $this->expiry[$hash] <= time();
+    }
+}
diff --git a/src/Repositories/RedisRepository.php b/src/Repositories/RedisRepository.php
index eb635c26..15917bc3 100644
--- a/src/Repositories/RedisRepository.php
+++ b/src/Repositories/RedisRepository.php
@@ -127,7 +127,9 @@ public function getExpiry(string $hash): ?int
     {
         // The number of seconds until the key will expire, or
         // null if the key does not exist or has no timeout.
-        return $this->redis->ttl($hash);
+        $ttl = $this->redis->ttl($hash);
+
+        return $ttl > 0 ? $ttl : null;
     }
 
     /**
diff --git a/tests/Repositories/ArrayRepositoryTest.php b/tests/Repositories/ArrayRepositoryTest.php
new file mode 100644
index 00000000..bc6816af
--- /dev/null
+++ b/tests/Repositories/ArrayRepositoryTest.php
@@ -0,0 +1,99 @@
+<?php
+
+use DirectoryTree\ActiveRedis\Repositories\ArrayRepository;
+
+it('can check if a hash exists', function () {
+    $repository = new ArrayRepository(['foo' => ['bar' => 'baz']]);
+
+    expect($repository->exists('foo'))->toBeTrue();
+    expect($repository->exists('bar'))->toBeFalse();
+});
+
+it('can chunk through hashes matching a pattern', function () {
+    $repository = new ArrayRepository([
+        'user:1' => [],
+        'user:2' => [],
+        'post:1' => [],
+        'user:3' => [],
+    ]);
+
+    $chunks = iterator_to_array($repository->chunk('user:*', 2));
+
+    expect($chunks)->toHaveCount(2);
+    expect($chunks[0])->toEqual(['user:1', 'user:2']);
+    expect($chunks[1])->toEqual(['user:3']);
+});
+
+it('can set and get a single attribute', function () {
+    $repository = new ArrayRepository;
+
+    $repository->setAttribute('foo', 'bar', 'baz');
+
+    expect($repository->getAttribute('foo', 'bar'))->toBe('baz');
+});
+
+it('can set and get multiple attributes', function () {
+    $repository = new ArrayRepository;
+
+    $repository->setAttributes('foo', ['bar' => 'baz', 'qux' => 'quux']);
+
+    expect($repository->getAttributes('foo'))->toEqual(['bar' => 'baz', 'qux' => 'quux']);
+});
+
+it('can delete attributes', function () {
+    $repository = new ArrayRepository(['foo' => ['bar' => 'baz', 'qux' => 'quux']]);
+
+    $repository->deleteAttributes('foo', 'bar');
+
+    expect($repository->getAttributes('foo'))->toEqual(['qux' => 'quux']);
+
+    $repository->deleteAttributes('foo', ['qux']);
+
+    expect($repository->getAttributes('foo'))->toEqual([]);
+});
+
+it('can delete a hash', function () {
+    $repository = new ArrayRepository(['foo' => ['bar' => 'baz']]);
+
+    $repository->delete('foo');
+
+    expect($repository->exists('foo'))->toBeFalse();
+});
+
+it('can set and get expiry', function () {
+    $repository = new ArrayRepository;
+
+    $repository->setExpiry('foo', 10);
+
+    expect($repository->getExpiry('foo'))->toBeGreaterThanOrEqual(9);
+});
+
+it('returns null for expiry of non-existent key', function () {
+    $repository = new ArrayRepository;
+
+    expect($repository->getExpiry('foo'))->toBeNull();
+});
+
+it('deletes expired hashes', function () {
+    $repository = new ArrayRepository;
+
+    $repository->setAttributes('foo', ['bar' => 'baz']);
+
+    $repository->setExpiry('foo', 1);
+
+    sleep(2);
+
+    expect($repository->getAttributes('foo'))->toEqual([]);
+});
+
+it('handles getting attributes from expired hash', function () {
+    $repository = new ArrayRepository;
+
+    $repository->setAttributes('foo', ['bar' => 'baz']);
+
+    $repository->setExpiry('foo', 1);
+
+    sleep(2);
+
+    expect($repository->getAttribute('foo', 'bar'))->toBeNull();
+});
diff --git a/tests/Repositories/RedisRepositoryTest.php b/tests/Repositories/RedisRepositoryTest.php
new file mode 100644
index 00000000..b7d3508a
--- /dev/null
+++ b/tests/Repositories/RedisRepositoryTest.php
@@ -0,0 +1,118 @@
+<?php
+
+use DirectoryTree\ActiveRedis\Repositories\RedisRepository;
+use Illuminate\Support\Facades\Redis;
+
+beforeEach(fn () => Redis::flushdb());
+
+it('can check if a hash exists', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('foo', ['bar' => 'baz']);
+
+    expect($repository->exists('foo'))->toBeTrue();
+    expect($repository->exists('bar'))->toBeFalse();
+
+    $repository->delete('foo');
+});
+
+it('can chunk through hashes matching a pattern', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('user:1', ['foo']);
+    $repository->setAttributes('user:2', ['foo']);
+    $repository->setAttributes('post:1', ['foo']);
+    $repository->setAttributes('user:3', ['foo']);
+
+    $chunks = iterator_to_array($repository->chunk('user:*', 2));
+
+    expect($chunks)->toBeGreaterThanOrEqual(1);
+});
+
+it('can set and get a single attribute', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttribute('foo', 'bar', 'baz');
+
+    expect($repository->getAttribute('foo', 'bar'))->toBe('baz');
+
+    $repository->delete('foo');
+});
+
+it('can set and get multiple attributes', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('foo', ['bar' => 'baz', 'qux' => 'quux']);
+
+    expect($repository->getAttributes('foo'))->toEqual(['bar' => 'baz', 'qux' => 'quux']);
+
+    $repository->delete('foo');
+});
+
+it('can delete attributes', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('foo', ['bar' => 'baz', 'qux' => 'quux']);
+
+    $repository->deleteAttributes('foo', 'bar');
+
+    expect($repository->getAttributes('foo'))->toEqual(['qux' => 'quux']);
+
+    $repository->deleteAttributes('foo', ['qux']);
+
+    expect($repository->getAttributes('foo'))->toEqual([]);
+
+    $repository->delete('foo');
+});
+
+it('can delete a hash', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('foo', ['bar' => 'baz']);
+
+    $repository->delete('foo');
+
+    expect($repository->exists('foo'))->toBeFalse();
+});
+
+it('can set and get expiry', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('foo', ['bar' => 'baz']);
+
+    $repository->setExpiry('foo', 10);
+
+    expect($repository->getExpiry('foo'))->toBeGreaterThanOrEqual(9);
+
+    $repository->delete('foo');
+});
+
+it('returns null for expiry of non-existent key', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    expect($repository->getExpiry('foo'))->toBeNull();
+});
+
+it('deletes expired hashes', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('foo', ['bar' => 'baz']);
+
+    $repository->setExpiry('foo', 1);
+
+    sleep(2);
+
+    expect($repository->getAttributes('foo'))->toEqual([]);
+});
+
+it('handles getting attributes from expired hash', function () {
+    $repository = new RedisRepository(Redis::connection());
+
+    $repository->setAttributes('foo', ['bar' => 'baz']);
+
+    $repository->setExpiry('foo', 1);
+
+    sleep(2);
+
+    expect($repository->getAttribute('foo', 'bar'))->toBeFalsy();
+});