diff --git a/README.md b/README.md
index 48ac0c46..f0bccb0f 100644
--- a/README.md
+++ b/README.md
@@ -95,6 +95,7 @@ ivy"io.github.iltotore::iron:version"
 | iron            | ✔️  | ✔️  | ✔️     |
 | iron-cats       | ✔️  | ✔️  | ✔️     |
 | iron-circe      | ✔️  | ✔️  | ✔️     |
+| iron-ciris      | ✔️  | ✔️  | ✔️     |
 | iron-jsoniter   | ✔️  | ✔️  | ✔️     |
 | iron-scalacheck | ✔️  | ✔️  | ❌      |
 | iron-zio        | ✔️  | ✔️  | ❌      |
diff --git a/build.sc b/build.sc
index 8ca0c5ef..423fcb7a 100644
--- a/build.sc
+++ b/build.sc
@@ -133,6 +133,7 @@ object docs extends BaseModule {
   def externalMappings = Map(
     ".*cats.*" -> ("scaladoc3", "https://javadoc.io/doc/org.typelevel/cats-docs_3/latest/"),
     ".*io.circe.*" -> ("scaladoc2", "https://circe.github.io/circe/api/"),
+    ".*ciris.*" -> ("scaladoc2", "https://cir.is/api/"),
     ".*com.github.plokhotnyuk.jsoniter_scala.core.*" -> ("scaladoc3", "https://www.javadoc.io/doc/com.github.plokhotnyuk.jsoniter-scala/jsoniter-scala-core_3/latest/"),
     ".*zio.json.*" -> ("scaladoc3", "https://javadoc.io/doc/dev.zio/zio-json_3/latest/"),
     ".*zio.prelude.*" -> ("scaladoc3", "https://javadoc.io/doc/dev.zio/zio-prelude-docs_3/latest/"),
diff --git a/ciris/src/io.github.iltotore.iron/ciris.scala b/ciris/src/io.github.iltotore.iron/ciris.scala
index 33ed4db4..25bcbe89 100644
--- a/ciris/src/io.github.iltotore.iron/ciris.scala
+++ b/ciris/src/io.github.iltotore.iron/ciris.scala
@@ -1,11 +1,23 @@
 package io.github.iltotore.iron
 
-import _root_.ciris.ConfigDecoder
-import cats.Show
-
+import _root_.ciris.{ConfigDecoder, ConfigError}
 
 object ciris:
 
-  inline given [T,A,B](using inline decoder: ConfigDecoder[T,A], inline constraint: _root_.io.github.iltotore.iron.Constraint[A, B], inline show: Show[A]): ConfigDecoder[T, A :| B] =
-    decoder.mapOption("")(_.refineOption)
+  /**
+   * A [[ConfigDecoder]] for refined types. Decodes to the underlying type then checks the constraint.
+   *
+   * @param decoder    the [[ConfigDecoder]] of the underlying type
+   * @param constraint the [[Constraint]] implementation to test the decoded value
+   */
+  inline given [In, A, C](using inline decoder: ConfigDecoder[In, A], inline constraint: Constraint[A, C]): ConfigDecoder[In, A :| C] =
+    decoder.mapEither((_, value) => value.refineEither[C].left.map(ConfigError(_)))
 
+  /**
+   * A [[ConfigDecoder]] for new types. Decodes to the underlying type then checks the constraint.
+   *
+   * @param decoder    the [[ConfigDecoder]] of the underlying type.
+   * @param mirror     the mirror of the [[RefinedTypeOps.Mirror]]
+   */
+  inline given [In, T](using mirror: RefinedTypeOps.Mirror[T], decoder: ConfigDecoder[In, mirror.IronType]): ConfigDecoder[In, T] =
+    decoder.asInstanceOf[ConfigDecoder[In, T]]
diff --git a/ciris/test/src/io/github/iltotore/iron/CirisSuite.scala b/ciris/test/src/io/github/iltotore/iron/CirisSuite.scala
index 2c2e8ea4..439fad25 100644
--- a/ciris/test/src/io/github/iltotore/iron/CirisSuite.scala
+++ b/ciris/test/src/io/github/iltotore/iron/CirisSuite.scala
@@ -1,19 +1,22 @@
 package io.github.iltotore.iron
 
 import _root_.ciris.ConfigDecoder
+import io.github.iltotore.iron.ciris.given
+import io.github.iltotore.iron.constraint.numeric.Positive
 import utest.*
-import ciris.given
-
 
 object CirisSuite extends TestSuite:
   val tests: Tests = Tests {
 
-    test("summon String => Int :| Pure") {
-      summon[ ConfigDecoder[String, Int :| Pure]]
-    }
+    test("decoder") {
+      test("ironType") {
+        test("success") - assert(summon[ConfigDecoder[String, Int :| Positive]].decode(None, "5") == Right(5))
+        test("failure") - assert(summon[ConfigDecoder[String, Int :| Positive]].decode(None, "-5").isLeft)
+      }
 
-    test("summon from Int => Int :| Pure") {
-      summon[ConfigDecoder[Int, Int :| Pure]]
+      test("newType") {
+        test("success") - assert(summon[ConfigDecoder[String, Temperature]].decode(None, "5") == Right(Temperature(5)))
+        test("failure") - assert(summon[ConfigDecoder[String, Temperature]].decode(None, "-5").isLeft)
+      }
     }
   }
-
diff --git a/ciris/test/src/io/github/iltotore/iron/RefinedOpsTypes.scala b/ciris/test/src/io/github/iltotore/iron/RefinedOpsTypes.scala
new file mode 100644
index 00000000..4b0c33c5
--- /dev/null
+++ b/ciris/test/src/io/github/iltotore/iron/RefinedOpsTypes.scala
@@ -0,0 +1,6 @@
+package io.github.iltotore.iron
+
+import io.github.iltotore.iron.constraint.numeric.Positive
+
+opaque type Temperature = Int :| Positive
+object Temperature extends RefinedTypeOps[Int, Positive, Temperature]
\ No newline at end of file
diff --git a/docs/_docs/modules/ciris.md b/docs/_docs/modules/ciris.md
new file mode 100644
index 00000000..0dd58f4d
--- /dev/null
+++ b/docs/_docs/modules/ciris.md
@@ -0,0 +1,59 @@
+---
+title: "Ciris Support"
+---
+
+# Ciris Support
+
+This module provides refined types Encoder/Decoder instances for [Ciris](https://circe.github.io/circe/).
+
+## Dependency
+
+SBT:
+
+```scala 
+libraryDependencies += "io.github.iltotore" %% "iron-ciris" % "version"
+```
+
+Mill:
+
+```scala 
+ivy"io.github.iltotore::iron-ciris:version"
+```
+
+### Following examples' dependencies
+
+SBT:
+
+```scala 
+libraryDependencies += "is.cir" %% "ciris" % "3.1.0"
+```
+
+Mill:
+
+```scala 
+ivy"is.cir::ciris::3.1.0"
+```
+
+## ConfigDecoder instances
+
+Iron provides `ConfigDecoder` instances for refined types:
+
+```scala 
+import cats.syntax.all.*
+import ciris.*
+
+import io.github.iltotore.iron.*
+import io.github.iltotore.iron.constraint.all.*
+import io.github.iltotore.iron.cats.given
+import io.github.iltotore.iron.ciris.given
+
+type Username = String :| (Not[Blank] & MaxLength[32])
+type Password = String :| (Not[Blank] & MinLength[9])
+
+case class DatabaseConfig(username: Username, password: Secret[Password])
+
+val databaseConfig: ConfigValue[Effect, DatabaseConfig] = (
+  env("DB_USERNAME").as[Username],
+  env("DB_PASSWORD").as[Password].secret
+).mapN(DatabaseConfig.apply)
+```
\ No newline at end of file
diff --git a/docs/sidebar.yml b/docs/sidebar.yml
index 7c172c0d..6f32d724 100644
--- a/docs/sidebar.yml
+++ b/docs/sidebar.yml
@@ -20,6 +20,7 @@ subsection:
     subsection:
       - page: modules/cats.md
       - page: modules/circe.md
+      - page: modules/ciris.md
       - page: modules/jsoniter.md
       - page: modules/scalacheck.md
       - page: modules/zio.md