diff --git a/build.sbt b/build.sbt
index 057c634..fcea9bb 100644
--- a/build.sbt
+++ b/build.sbt
@@ -99,3 +99,15 @@ lazy val magnumZio = project
       "org.postgresql" % "postgresql" % postgresDriverVersion % Test
     )
   )
+
+lazy val magnumCats = project
+  .in(file("magnum-cats-effect"))
+  .dependsOn(magnum % "compile->compile;test->test")
+  .settings(
+    Test / fork := true,
+    publish / skip := false,
+    libraryDependencies ++= Seq(
+      "org.typelevel" %% "cats-effect" % "3.5.7" % Provided,
+      "org.tpolecat" %% "natchez-core" % "0.3.7" % Provided
+    )
+  )
diff --git a/magnum-cats-effect/src/main/scala/com/augustnagro/magnum/magcats/cats-effect.scala b/magnum-cats-effect/src/main/scala/com/augustnagro/magnum/magcats/cats-effect.scala
new file mode 100644
index 0000000..fa60fb9
--- /dev/null
+++ b/magnum-cats-effect/src/main/scala/com/augustnagro/magnum/magcats/cats-effect.scala
@@ -0,0 +1,122 @@
+package com.augustnagro.magnum.magcats
+
+import javax.sql.DataSource
+import com.augustnagro.magnum.DbCon
+import cats.effect.IO
+import com.augustnagro.magnum.Transactor
+import cats.effect.kernel.Resource
+import java.sql.Connection
+import com.augustnagro.magnum.DbTx
+import cats.effect.unsafe.IORuntime
+import scala.util.control.NonFatal
+import natchez.Trace
+
+/** Executes a given query on a given DataSource
+  *
+  * Re-implementation for IO of
+  * [[com.augustnagro.magnum.connect(dataSource: DataSource)]]
+  *
+  * Usage:
+  * {{{
+  *   import com.augustnagro.magnum.magcats.*
+  *
+  *   connect(datasource) { cn ?=> repo.findById(id) }
+  * }}}
+  */
+def connect[A](dataSource: DataSource)(q: DbCon ?=> A)(using
+    trace: Trace[IO]
+): IO[A] =
+  connect(Transactor(dataSource))(q)
+
+/** Executes a given query on a given Transactor
+  *
+  * Re-implementation for IO of
+  * [[com.augustnagro.magnum.connect(dataSource: DataSource)]]
+  *
+  * Usage:
+  * {{{
+  *   import com.augustnagro.magnum.magcats.*
+  *
+  *   connect(transactor) { cn ?=> repo.findById(id) }
+  * }}}
+  */
+def connect[A](
+    transactor: Transactor
+)(q: DbCon ?=> A)(using trace: Trace[IO]): IO[A] =
+  Resource
+    .fromAutoCloseable(IO.interruptible(transactor.dataSource.getConnection()))
+    .use { cn =>
+      IO.interruptible {
+        transactor.connectionConfig(cn)
+        q(using DbCon(cn, transactor.sqlLogger))
+      }
+    }
+
+/** Executes a given transaction on a given DataSource
+  *
+  * Re-implementation for IO of
+  * [[com.augustnagro.magnum.transact(transactor: Transactor)]]
+  *
+  * Usage:
+  * {{{
+  *   import com.augustnagro.magnum.magcats.*
+  *
+  *   transact(dataSource) { tx ?=> repo.insertReturning(creator) }
+  * }}}
+  */
+def transact[A](dataSource: DataSource)(q: DbTx ?=> A)(using
+    trace: Trace[IO]
+): IO[A] =
+  transact(Transactor(dataSource))(q)
+
+/** Executes a given transaction on a given DataSource
+  *
+  * Re-implementation for IO of
+  * [[com.augustnagro.magnum.transact(transactor: Transactor, connectionConfig: Connection => Unit)]]
+  *
+  * Usage:
+  * {{{
+  *   import com.augustnagro.magnum.magcats.*
+  *
+  *   transact(dataSource, ...) { tx ?=> repo.insertReturning(creator) }
+  * }}}
+  */
+def transact[A](dataSource: DataSource, connectionConfig: Connection => Unit)(
+    q: DbTx ?=> A
+)(using trace: Trace[IO]): IO[A] =
+  val transactor =
+    Transactor(dataSource = dataSource, connectionConfig = connectionConfig)
+  transact(transactor)(q)
+
+/** Executes a given transaction on a given Transactor
+  *
+  * Re-implementation for IO of
+  * [[com.augustnagro.magnum.transact(transactor: Transactor)]]
+  *
+  * Usage:
+  * {{{
+  *   import com.augustnagro.magnum.magcats.*
+  *
+  *   transact(transactor) { tx ?=> repo.insertReturning(creator) }
+  * }}}
+  */
+def transact[A](
+    transactor: Transactor
+)(q: DbTx ?=> A)(using trace: Trace[IO]): IO[A] =
+  Resource
+    .fromAutoCloseable(IO.interruptible(transactor.dataSource.getConnection()))
+    .use { cn =>
+      IO.blocking {
+        transactor.connectionConfig(cn)
+        cn.setAutoCommit(false)
+        try {
+          val res = q(using DbTx(cn, transactor.sqlLogger))
+          cn.commit()
+          res
+        } catch {
+          case NonFatal(t) =>
+            cn.rollback()
+            throw t
+        }
+      }
+    }
diff --git a/magnum-cats-effect/src/test/scala/com/augustnagro/magnum/magcats/ImmutableRepoCatsEffectTests.scala b/magnum-cats-effect/src/test/scala/com/augustnagro/magnum/magcats/ImmutableRepoCatsEffectTests.scala
new file mode 100644
index 0000000..014a841
--- /dev/null
+++ b/magnum-cats-effect/src/test/scala/com/augustnagro/magnum/magcats/ImmutableRepoCatsEffectTests.scala
@@ -0,0 +1,198 @@
+package com.augustnagro.magnum.magcats
+
+import com.augustnagro.magnum.*
+import shared.Color
+import munit.FunSuite
+import cats.effect.IO
+import cats.effect.std.Dispatcher
+import cats.effect.unsafe.IORuntime
+
+import java.sql.Connection
+import java.time.OffsetDateTime
+import scala.util.{Success, Using}
+import cats.effect.Trace
+
+def immutableRepoCatsEffectTests(
+    suite: FunSuite,
+    dbType: DbType,
+    xa: () => Transactor
+)(using
+    munit.Location,
+    DbCodec[OffsetDateTime]
+): Unit =
+  import suite.*
+
+  given IORuntime = IORuntime.global
+  given natchez.Trace[IO] = natchez.Trace.Implicits.noop
+
+  def runIO[A](io: IO[A]): A =
+    io.unsafeRunSync()
+
+  @Table(dbType, SqlNameMapper.CamelToSnakeCase)
+  case class Car(
+      model: String,
+      @Id id: Long,
+      topSpeed: Int,
+      @SqlName("vin") vinNumber: Option[Int],
+      color: Color,
+      created: OffsetDateTime
+  ) derives DbCodec
+
+  val carRepo = ImmutableRepo[Car, Long]
+  val car = TableInfo[Car, Car, Long]
+
+  val allCars = Vector(
+    Car(
+      model = "McLaren Senna",
+      id = 1L,
+      topSpeed = 208,
+      vinNumber = Some(123),
+      color = Color.Red,
+      created = OffsetDateTime.parse("2024-11-24T22:17:30.000000000Z")
+    ),
+    Car(
+      model = "Ferrari F8 Tributo",
+      id = 2L,
+      topSpeed = 212,
+      vinNumber = Some(124),
+      color = Color.Green,
+      created = OffsetDateTime.parse("2024-11-24T22:17:31.000000000Z")
+    ),
+    Car(
+      model = "Aston Martin Superleggera",
+      id = 3L,
+      topSpeed = 211,
+      vinNumber = None,
+      color = Color.Blue,
+      created = OffsetDateTime.parse("2024-11-24T22:17:32.000000000Z")
+    )
+  )
+
+  test("count"):
+    val count =
+      runIO:
+        magcats.connect(xa()):
+          carRepo.count
+    assert(count == 3L)
+
+  test("existsById"):
+    val (exists3, exists4) =
+      runIO:
+        magcats.connect(xa()):
+          carRepo.existsById(3L) -> carRepo.existsById(4L)
+    assert(exists3)
+    assert(!exists4)
+
+  test("findAll"):
+    val cars =
+      runIO:
+        magcats.connect(xa()):
+          carRepo.findAll
+    assert(cars == allCars)
+
+  test("findById"):
+    val (exists3, exists4) =
+      runIO:
+        magcats.connect(xa()):
+          carRepo.findById(3L) -> carRepo.findById(4L)
+    assert(exists3.get == allCars.last)
+    assert(exists4 == None)
+
+  test("findAllByIds"):
+    assume(dbType != ClickhouseDbType)
+    assume(dbType != MySqlDbType)
+    assume(dbType != OracleDbType)
+    assume(dbType != SqliteDbType)
+    val ids =
+      runIO:
+        magcats.connect(xa()):
+          carRepo.findAllById(Vector(1L, 3L)).map(_.id)
+    assert(ids == Vector(1L, 3L))
+
+  test("serializable transaction"):
+    val count =
+      runIO:
+        magcats.transact(xa().copy(connectionConfig = withSerializable)):
+          carRepo.count
+    assert(count == 3L)
+
+  def withSerializable(con: Connection): Unit =
+    con.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE)
+
+  test("select query"):
+    val minSpeed: Int = 210
+    val query =
+      sql"select ${car.all} from $car where ${car.topSpeed} > $minSpeed"
+        .query[Car]
+    val result =
+      runIO:
+        magcats.connect(xa()):
+          query.run()
+    assertNoDiff(
+      query.frag.sqlString,
+      "select model, id, top_speed, vin, color, created from car where top_speed > ?"
+    )
+    assert(query.frag.params == Vector(minSpeed))
+    assert(result == allCars.tail)
+
+  test("select query with aliasing"):
+    val minSpeed = 210
+    val cAlias = car.alias("c")
+    val query =
+      sql"select ${cAlias.all} from $cAlias where ${cAlias.topSpeed} > $minSpeed"
+        .query[Car]
+    val result =
+      runIO:
+        magcats.connect(xa()):
+          query.run()
+    assertNoDiff(
+      query.frag.sqlString,
+      "select c.model, c.id, c.top_speed, c.vin, c.color, c.created from car c where c.top_speed > ?"
+    )
+    assert(query.frag.params == Vector(minSpeed))
+    assert(result == allCars.tail)
+
+  test("select via option"):
+    val vin = Some(124)
+    val cars =
+      runIO:
+        magcats.connect(xa()):
+          sql"select * from car where vin = $vin"
+            .query[Car]
+            .run()
+    assert(cars == allCars.filter(_.vinNumber == vin))
+
+  test("tuple select"):
+    val tuples =
+      runIO:
+        magcats.connect(xa()):
+          sql"select model, color from car where id = 2"
+            .query[(String, Color)]
+            .run()
+    assert(tuples == Vector(allCars(1).model -> allCars(1).color))
+
+  test("reads null int as None and not Some(0)"):
+    val maybeCar =
+      runIO:
+        magcats.connect(xa()):
+          carRepo.findById(3L)
+    assert(maybeCar.get.vinNumber == None)
+
+  test("created timestamps should match"):
+    val allCars =
+      runIO:
+        magcats.connect(xa()):
+          carRepo.findAll
+    assert(allCars.map(_.created) == allCars.map(_.created))
+
+  test(".query iterator"):
+    val carsCount =
+      runIO:
+        magcats.connect(xa()):
+          Using.Manager(implicit use =>
+            val it = sql"SELECT * FROM car".query[Car].iterator()
+            it.map(_.id).size
+          )
+    assert(carsCount == Success(3))
+
+end immutableRepoCatsEffectTests
diff --git a/magnum-cats-effect/src/test/scala/com/augustnagro/magnum/magcats/PgCatsEffectTests.scala b/magnum-cats-effect/src/test/scala/com/augustnagro/magnum/magcats/PgCatsEffectTests.scala
new file mode 100644
index 0000000..42c6ccd
--- /dev/null
+++ b/magnum-cats-effect/src/test/scala/com/augustnagro/magnum/magcats/PgCatsEffectTests.scala
@@ -0,0 +1,49 @@
+package com.augustnagro.magnum.magzio
+
+import com.augustnagro.magnum.*
+import com.dimafeng.testcontainers.PostgreSQLContainer
+import com.dimafeng.testcontainers.munit.fixtures.TestContainersFixtures
+import munit.{AnyFixture, FunSuite, Location}
+import org.postgresql.ds.PGSimpleDataSource
+import org.testcontainers.utility.DockerImageName
+
+import java.nio.file.{Files, Path}
+import scala.util.Using
+import scala.util.Using.Manager
+import com.augustnagro.magnum.magcats.immutableRepoCatsEffectTests
+
+class PgCatsEffectTests extends FunSuite, TestContainersFixtures:
+
+  immutableRepoCatsEffectTests(this, PostgresDbType, xa)
+
+  val pgContainer = ForAllContainerFixture(
+    PostgreSQLContainer
+      .Def(dockerImageName = DockerImageName.parse("postgres:17.0"))
+      .createContainer()
+  )
+
+  override def munitFixtures: Seq[AnyFixture[_]] =
+    super.munitFixtures :+ pgContainer
+
+  def xa(): Transactor =
+    val ds = PGSimpleDataSource()
+    val pg = pgContainer()
+    ds.setUrl(pg.jdbcUrl)
+    ds.setUser(pg.username)
+    ds.setPassword(pg.password)
+    val tableDDLs = Vector(
+      "/pg/car.sql",
+      "/pg/person.sql",
+      "/pg/my-user.sql",
+      "/pg/no-id.sql",
+      "/pg/big-dec.sql"
+    ).map(p => Files.readString(Path.of(getClass.getResource(p).toURI)))
+
+    Manager(use =>
+      val con = use(ds.getConnection)
+      val stmt = use(con.createStatement)
+      for ddl <- tableDDLs do stmt.execute(ddl)
+    ).get
+    Transactor(ds)
+  end xa
+end PgCatsEffectTests