diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip42RelayAuth/RelayAuthEvent.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip42RelayAuth/RelayAuthEvent.kt
index acd65b79a..9b73c43b0 100644
--- a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip42RelayAuth/RelayAuthEvent.kt
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip42RelayAuth/RelayAuthEvent.kt
@@ -23,8 +23,10 @@ package com.vitorpamplona.quartz.nip42RelayAuth
 import androidx.compose.runtime.Immutable
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip42RelayAuth.tags.ChallengeTag
 import com.vitorpamplona.quartz.nip42RelayAuth.tags.RelayTag
 import com.vitorpamplona.quartz.utils.TimeUtils
@@ -45,6 +47,17 @@ class RelayAuthEvent(
     companion object {
         const val KIND = 22242
 
+        fun build(
+            relay: NormalizedRelayUrl,
+            challenge: String,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<RelayAuthEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, "", createdAt) {
+            relay(relay)
+            challenge(challenge)
+            initializer()
+        }
+
         suspend fun create(
             relay: NormalizedRelayUrl,
             challenge: String,
diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip42RelayAuth/TagArrayBuilderExt.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip42RelayAuth/TagArrayBuilderExt.kt
new file mode 100644
index 000000000..608b65fa5
--- /dev/null
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip42RelayAuth/TagArrayBuilderExt.kt
@@ -0,0 +1,30 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip42RelayAuth
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip42RelayAuth.tags.ChallengeTag
+import com.vitorpamplona.quartz.nip42RelayAuth.tags.RelayTag
+
+fun TagArrayBuilder<RelayAuthEvent>.relay(relay: NormalizedRelayUrl) = addUnique(RelayTag.assemble(relay))
+
+fun TagArrayBuilder<RelayAuthEvent>.challenge(challenge: String) = addUnique(ChallengeTag.assemble(challenge))