diff --git a/tests/Unit/Service/Nostr/NostrEventBuilderTest.php b/tests/Unit/Service/Nostr/NostrEventBuilderTest.php
new file mode 100644
index 0000000..9194a16
--- /dev/null
+++ b/tests/Unit/Service/Nostr/NostrEventBuilderTest.php
@@ -0,0 +1,203 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Service\Nostr;
+
+use App\Dto\AdvancedMetadata;
+use App\Dto\ZapSplit;
+use App\Entity\Article;
+use App\Enum\KindsEnum;
+use App\Service\Nostr\NostrEventBuilder;
+use PHPUnit\Framework\TestCase;
+
+class NostrEventBuilderTest extends TestCase
+{
+    private NostrEventBuilder $builder;
+
+    protected function setUp(): void
+    {
+        $this->builder = new NostrEventBuilder();
+    }
+
+    public function testBuildBasicTags(): void
+    {
+        $article = new Article();
+        $article->setSlug('test-article');
+        $article->setTitle('Test Article');
+        $article->setSummary('A test summary');
+        $article->setImage('https://example.com/image.jpg');
+        $article->setTopics(['nostr', 'testing']);
+        $article->setPublishedAt(new \DateTimeImmutable('@1609459200')); // 2021-01-01
+
+        $tags = $this->builder->buildTags($article, null);
+
+        $this->assertContains(['d', 'test-article'], $tags);
+        $this->assertContains(['title', 'Test Article'], $tags);
+        $this->assertContains(['summary', 'A test summary'], $tags);
+        $this->assertContains(['image', 'https://example.com/image.jpg'], $tags);
+        $this->assertContains(['t', 'nostr'], $tags);
+        $this->assertContains(['t', 'testing'], $tags);
+        $this->assertContains(['published_at', '1609459200'], $tags);
+    }
+
+    public function testBuildDoNotRepublishTag(): void
+    {
+        $article = new Article();
+        $article->setSlug('test');
+        $article->setTitle('Test');
+
+        $metadata = new AdvancedMetadata();
+        $metadata->doNotRepublish = true;
+
+        $tags = $this->builder->buildTags($article, $metadata);
+
+        $this->assertContains(['L', 'rights.decent.newsroom'], $tags);
+        $this->assertContains(['l', 'no-republish', 'rights.decent.newsroom'], $tags);
+    }
+
+    public function testBuildLicenseTags(): void
+    {
+        $article = new Article();
+        $article->setSlug('test');
+        $article->setTitle('Test');
+
+        $metadata = new AdvancedMetadata();
+        $metadata->license = 'CC-BY-4.0';
+
+        $tags = $this->builder->buildTags($article, $metadata);
+
+        $this->assertContains(['L', 'spdx.org/licenses'], $tags);
+        $this->assertContains(['l', 'CC-BY-4.0', 'spdx.org/licenses'], $tags);
+    }
+
+    public function testBuildAllRightsReservedTag(): void
+    {
+        $article = new Article();
+        $article->setSlug('test');
+        $article->setTitle('Test');
+
+        $metadata = new AdvancedMetadata();
+        $metadata->license = 'All rights reserved';
+
+        $tags = $this->builder->buildTags($article, $metadata);
+
+        $this->assertContains(['L', 'rights.decent.newsroom'], $tags);
+        $this->assertContains(['l', 'all-rights-reserved', 'rights.decent.newsroom'], $tags);
+    }
+
+    public function testBuildZapSplitTags(): void
+    {
+        $article = new Article();
+        $article->setSlug('test');
+        $article->setTitle('Test');
+
+        $metadata = new AdvancedMetadata();
+        $metadata->zapSplits = [
+            new ZapSplit('82341f882b6eabcd2ba7f1ef90aad961cf074af15b9ef44a09f9d2a8fbfbe6a2', 'wss://relay.damus.io', 2),
+            new ZapSplit('3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d', 'wss://relay.nostr.band', 1),
+        ];
+
+        $tags = $this->builder->buildTags($article, $metadata);
+
+        $this->assertContains(
+            ['zap', '82341f882b6eabcd2ba7f1ef90aad961cf074af15b9ef44a09f9d2a8fbfbe6a2', 'wss://relay.damus.io', '2'],
+            $tags
+        );
+        $this->assertContains(
+            ['zap', '3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d', 'wss://relay.nostr.band', '1'],
+            $tags
+        );
+    }
+
+    public function testBuildContentWarningTag(): void
+    {
+        $article = new Article();
+        $article->setSlug('test');
+        $article->setTitle('Test');
+
+        $metadata = new AdvancedMetadata();
+        $metadata->contentWarning = 'graphic content';
+
+        $tags = $this->builder->buildTags($article, $metadata);
+
+        $this->assertContains(['content-warning', 'graphic content'], $tags);
+    }
+
+    public function testBuildExpirationTag(): void
+    {
+        $article = new Article();
+        $article->setSlug('test');
+        $article->setTitle('Test');
+
+        $metadata = new AdvancedMetadata();
+        $metadata->expirationTimestamp = 1735689600; // 2025-01-01
+
+        $tags = $this->builder->buildTags($article, $metadata);
+
+        $this->assertContains(['expiration', '1735689600'], $tags);
+    }
+
+    public function testBuildProtectedTag(): void
+    {
+        $article = new Article();
+        $article->setSlug('test');
+        $article->setTitle('Test');
+
+        $metadata = new AdvancedMetadata();
+        $metadata->isProtected = true;
+
+        $tags = $this->builder->buildTags($article, $metadata);
+
+        $this->assertContains(['-'], $tags);
+    }
+
+    public function testCalculateSharesEqualDistribution(): void
+    {
+        $splits = [
+            new ZapSplit('pubkey1'),
+            new ZapSplit('pubkey2'),
+            new ZapSplit('pubkey3'),
+        ];
+
+        $shares = $this->builder->calculateShares($splits);
+
+        $this->assertCount(3, $shares);
+        $this->assertEquals(33.333333333333, $shares[0], '', 0.01);
+        $this->assertEquals(33.333333333333, $shares[1], '', 0.01);
+        $this->assertEquals(33.333333333333, $shares[2], '', 0.01);
+    }
+
+    public function testCalculateSharesWeightedDistribution(): void
+    {
+        $splits = [
+            new ZapSplit('pubkey1', null, 2),
+            new ZapSplit('pubkey2', null, 1),
+            new ZapSplit('pubkey3', null, 1),
+        ];
+
+        $shares = $this->builder->calculateShares($splits);
+
+        $this->assertCount(3, $shares);
+        $this->assertEquals(50.0, $shares[0]);
+        $this->assertEquals(25.0, $shares[1]);
+        $this->assertEquals(25.0, $shares[2]);
+    }
+
+    public function testConvertNpubToHex(): void
+    {
+        // This is a test npub (you may need to adjust based on actual implementation)
+        $hex = '82341f882b6eabcd2ba7f1ef90aad961cf074af15b9ef44a09f9d2a8fbfbe6a2';
+
+        // Test hex passthrough
+        $result = $this->builder->convertToHex($hex);
+        $this->assertEquals($hex, $result);
+    }
+
+    public function testConvertInvalidPubkeyThrowsException(): void
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->builder->convertToHex('invalid-pubkey');
+    }
+}
+
diff --git a/tests/Unit/Service/Nostr/NostrEventParserTest.php b/tests/Unit/Service/Nostr/NostrEventParserTest.php
new file mode 100644
index 0000000..9227307
--- /dev/null
+++ b/tests/Unit/Service/Nostr/NostrEventParserTest.php
@@ -0,0 +1,168 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Service\Nostr;
+
+use App\Service\Nostr\NostrEventParser;
+use PHPUnit\Framework\TestCase;
+
+class NostrEventParserTest extends TestCase
+{
+    private NostrEventParser $parser;
+
+    protected function setUp(): void
+    {
+        $this->parser = new NostrEventParser();
+    }
+
+    public function testParseDoNotRepublishTag(): void
+    {
+        $tags = [
+            ['L', 'rights.decent.newsroom'],
+            ['l', 'no-republish', 'rights.decent.newsroom'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertTrue($metadata->doNotRepublish);
+    }
+
+    public function testParseLicenseTag(): void
+    {
+        $tags = [
+            ['L', 'spdx.org/licenses'],
+            ['l', 'CC-BY-4.0', 'spdx.org/licenses'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertEquals('CC-BY-4.0', $metadata->license);
+    }
+
+    public function testParseAllRightsReservedTag(): void
+    {
+        $tags = [
+            ['L', 'rights.decent.newsroom'],
+            ['l', 'all-rights-reserved', 'rights.decent.newsroom'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertEquals('All rights reserved', $metadata->license);
+    }
+
+    public function testParseZapSplitTags(): void
+    {
+        $tags = [
+            ['zap', '82341f882b6eabcd2ba7f1ef90aad961cf074af15b9ef44a09f9d2a8fbfbe6a2', 'wss://relay.damus.io', '2'],
+            ['zap', '3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d', 'wss://relay.nostr.band', '1'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertCount(2, $metadata->zapSplits);
+        $this->assertEquals('wss://relay.damus.io', $metadata->zapSplits[0]->relay);
+        $this->assertEquals(2, $metadata->zapSplits[0]->weight);
+        $this->assertEquals('wss://relay.nostr.band', $metadata->zapSplits[1]->relay);
+        $this->assertEquals(1, $metadata->zapSplits[1]->weight);
+    }
+
+    public function testParseContentWarningTag(): void
+    {
+        $tags = [
+            ['content-warning', 'graphic content'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertEquals('graphic content', $metadata->contentWarning);
+    }
+
+    public function testParseExpirationTag(): void
+    {
+        $tags = [
+            ['expiration', '1735689600'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertEquals(1735689600, $metadata->expirationTimestamp);
+    }
+
+    public function testParseProtectedTag(): void
+    {
+        $tags = [
+            ['-'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertTrue($metadata->isProtected);
+    }
+
+    public function testParseMultipleAdvancedTags(): void
+    {
+        $tags = [
+            ['d', 'test-article'],
+            ['title', 'Test Article'],
+            ['L', 'rights.decent.newsroom'],
+            ['l', 'no-republish', 'rights.decent.newsroom'],
+            ['L', 'spdx.org/licenses'],
+            ['l', 'CC-BY-NC-ND-4.0', 'spdx.org/licenses'],
+            ['zap', '82341f882b6eabcd2ba7f1ef90aad961cf074af15b9ef44a09f9d2a8fbfbe6a2', 'wss://relay.damus.io', '2'],
+            ['zap', '3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d', '', '1'],
+            ['content-warning', 'spoilers'],
+            ['expiration', '1735689600'],
+            ['-'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        $this->assertTrue($metadata->doNotRepublish);
+        $this->assertEquals('CC-BY-NC-ND-4.0', $metadata->license);
+        $this->assertCount(2, $metadata->zapSplits);
+        $this->assertEquals('spoilers', $metadata->contentWarning);
+        $this->assertEquals(1735689600, $metadata->expirationTimestamp);
+        $this->assertTrue($metadata->isProtected);
+    }
+
+    public function testExtractArticleData(): void
+    {
+        $tags = [
+            ['d', 'my-article-slug'],
+            ['title', 'My Article Title'],
+            ['summary', 'A brief summary'],
+            ['image', 'https://example.com/image.jpg'],
+            ['published_at', '1609459200'],
+            ['t', 'nostr'],
+            ['t', 'testing'],
+        ];
+
+        $data = $this->parser->extractArticleData($tags);
+
+        $this->assertEquals('my-article-slug', $data['slug']);
+        $this->assertEquals('My Article Title', $data['title']);
+        $this->assertEquals('A brief summary', $data['summary']);
+        $this->assertEquals('https://example.com/image.jpg', $data['image']);
+        $this->assertCount(2, $data['topics']);
+        $this->assertContains('nostr', $data['topics']);
+        $this->assertContains('testing', $data['topics']);
+        $this->assertInstanceOf(\DateTimeImmutable::class, $data['publishedAt']);
+    }
+
+    public function testPreserveUnknownTags(): void
+    {
+        $tags = [
+            ['d', 'test'],
+            ['custom-tag', 'custom-value'],
+            ['another-unknown', 'value1', 'value2'],
+        ];
+
+        $metadata = $this->parser->parseAdvancedMetadata($tags);
+
+        // Unknown tags should be preserved in extraTags
+        $this->assertCount(2, $metadata->extraTags);
+    }
+}
+