diff --git a/protobuf/js/src/main/scala/fluence/codec/Uint8ArrayCodecs.scala b/bits/js/src/main/scala/fluence/codec/bits/BitsUint8Codecs.scala
similarity index 79%
rename from protobuf/js/src/main/scala/fluence/codec/Uint8ArrayCodecs.scala
rename to bits/js/src/main/scala/fluence/codec/bits/BitsUint8Codecs.scala
index ed20768..e6873b4 100644
--- a/protobuf/js/src/main/scala/fluence/codec/Uint8ArrayCodecs.scala
+++ b/bits/js/src/main/scala/fluence/codec/bits/BitsUint8Codecs.scala
@@ -15,26 +15,18 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package fluence.codec
+package fluence.codec.bits
 
+import fluence.codec.PureCodec
 import scodec.bits.ByteVector
 
-import scala.language.higherKinds
-
 import scala.scalajs.js.typedarray.Uint8Array
 import scala.scalajs.js.JSConverters._
 
-object Uint8ArrayCodecs {
-
+object BitsUint8Codecs {
   implicit val byteVectorUint8Array: PureCodec[Uint8Array, ByteVector] =
     PureCodec.liftB(
       uint8 ⇒ ByteVector(uint8.toArray.map(_.toByte)),
       vec ⇒ new Uint8Array(vec.toArray.map(_.toShort).toJSArray)
     )
-
-  implicit val byteArrayUint8Array: PureCodec[Uint8Array, Array[Byte]] =
-    PureCodec.liftB(
-      uint8 ⇒ uint8.toArray.map(_.toByte),
-      arr ⇒ new Uint8Array(arr.toJSArray)
-    )
 }
diff --git a/bits/src/main/scala/fluence/codec/bits/BitsCodecs.scala b/bits/src/main/scala/fluence/codec/bits/BitsCodecs.scala
new file mode 100644
index 0000000..ffb6dbb
--- /dev/null
+++ b/bits/src/main/scala/fluence/codec/bits/BitsCodecs.scala
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2017  Fluence Labs Limited
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package fluence.codec.bits
+
+import fluence.codec.{CodecError, PureCodec}
+import scodec.bits.{Bases, ByteVector}
+
+/**
+ * Implicit codecs for scodec data structures.
+ */
+object BitsCodecs {
+  import PureCodec.{liftB, liftEitherB}
+
+  implicit val byteArrayToVector: PureCodec[Array[Byte], ByteVector] =
+    liftB(ByteVector.apply, _.toArray)
+
+  // Notice the use of default Base64 alphabet
+  implicit val base64ToVector: PureCodec[String, ByteVector] =
+    base64AlphabetToVector(Bases.Alphabets.Base64)
+
+  def base64AlphabetToVector(alphabet: Bases.Base64Alphabet): PureCodec[String, ByteVector] =
+    liftEitherB(
+      str ⇒
+        ByteVector
+          .fromBase64Descriptive(str, alphabet)
+          .left
+          .map(CodecError(_)),
+      vec ⇒ Right(vec.toBase64(alphabet))
+    )
+
+}
diff --git a/bits/src/test/scala/fluence/codec/bits/BitsCodecsSpec.scala b/bits/src/test/scala/fluence/codec/bits/BitsCodecsSpec.scala
new file mode 100644
index 0000000..131b369
--- /dev/null
+++ b/bits/src/test/scala/fluence/codec/bits/BitsCodecsSpec.scala
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2017  Fluence Labs Limited
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package fluence.codec.bits
+
+import cats.Id
+import cats.syntax.compose._
+import org.scalatest.prop.Checkers
+import org.scalatest.{Matchers, WordSpec}
+import scodec.bits.ByteVector
+import BitsCodecs._
+import fluence.codec.PureCodec
+
+class BitsCodecsSpec extends WordSpec with Matchers with Checkers {
+  "BitsCodecs" should {
+    "convert base64 strings to byte vectors and vice versa" in {
+
+      val arrCodec = implicitly[PureCodec[Array[Byte], ByteVector]]
+      val b64Codec = implicitly[PureCodec[ByteVector, String]]
+
+      check { (bytes: List[Byte]) ⇒
+        (arrCodec andThen arrCodec.swap).direct.apply[Id](bytes.toArray).value.map(_.toList).contains(bytes) &&
+        (arrCodec andThen b64Codec andThen b64Codec.swap andThen arrCodec.swap).direct
+          .apply[Id](bytes.toArray)
+          .value
+          .map(_.toList)
+          .contains(bytes)
+      }
+
+      b64Codec.inverse[Id]("wrong input!").value.isLeft shouldBe true
+    }
+  }
+}
diff --git a/circe/src/main/scala/fluence/codec/circe/CirceCodecs.scala b/circe/src/main/scala/fluence/codec/circe/CirceCodecs.scala
new file mode 100644
index 0000000..580d8dd
--- /dev/null
+++ b/circe/src/main/scala/fluence/codec/circe/CirceCodecs.scala
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2017  Fluence Labs Limited
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package fluence.codec.circe
+
+import fluence.codec.{CodecError, PureCodec}
+import io.circe._
+
+object CirceCodecs {
+
+  implicit def circeJsonCodec[T](encoder: Encoder[T], decoder: Decoder[T]): PureCodec[T, Json] =
+    PureCodec.liftEitherB[T, Json](
+      t ⇒ Right(encoder.apply(t)),
+      json ⇒ decoder.decodeJson(json).left.map(f ⇒ CodecError("Cannot decode json value", causedBy = Some(f)))
+    )
+
+  implicit val circeJsonParseCodec: PureCodec[Json, String] =
+    PureCodec.liftEitherB(
+      json ⇒ Right(json.noSpaces),
+      str ⇒ parser.parse(str).left.map(f ⇒ CodecError("Cannot parse json string", causedBy = Some(f)))
+    )
+
+}
diff --git a/core/js/src/main/scala/fluence/codec/Uint8Codecs.scala b/core/js/src/main/scala/fluence/codec/Uint8Codecs.scala
new file mode 100644
index 0000000..0325eac
--- /dev/null
+++ b/core/js/src/main/scala/fluence/codec/Uint8Codecs.scala
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2017  Fluence Labs Limited
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package fluence.codec
+
+import scala.scalajs.js.JSConverters._
+import scala.scalajs.js.typedarray.Uint8Array
+
+object Uint8Codecs {
+
+  implicit val byteArrayUint8Array: PureCodec[Uint8Array, Array[Byte]] =
+    PureCodec.liftB(
+      uint8 ⇒ uint8.toArray.map(_.toByte),
+      arr ⇒ new Uint8Array(arr.toJSArray)
+    )
+}
diff --git a/core/src/main/scala/fluence/codec/Codec.scala b/core/src/main/scala/fluence/codec/Codec.scala
index 377892c..04146e5 100644
--- a/core/src/main/scala/fluence/codec/Codec.scala
+++ b/core/src/main/scala/fluence/codec/Codec.scala
@@ -18,9 +18,8 @@
 package fluence.codec
 
 import cats.data.Kleisli
-import cats.{Applicative, ApplicativeError, FlatMap, Traverse}
+import cats.{Applicative, FlatMap, Traverse}
 import cats.syntax.applicative._
-import scodec.bits.ByteVector
 
 import scala.language.{higherKinds, implicitConversions}
 
@@ -31,6 +30,10 @@ import scala.language.{higherKinds, implicitConversions}
  * @tparam B The type of binary representation
  * @tparam F Encoding/decoding effect
  */
+@deprecated(
+  "Codec is planned for removing soon, as it's impure and not properly tested. Use PureCodec instead.",
+  "6.4.2018"
+)
 final case class Codec[F[_], A, B](encode: A ⇒ F[B], decode: B ⇒ F[A]) {
   self ⇒
 
@@ -47,6 +50,10 @@ final case class Codec[F[_], A, B](encode: A ⇒ F[B], decode: B ⇒ F[A]) {
   def swap: Codec[F, B, A] = Codec(decode, encode)
 }
 
+@deprecated(
+  "Codec is planned for removing soon, as it's impure and not properly tested. Use PureCodec instead.",
+  "6.4.2018"
+)
 object Codec {
   implicit def identityCodec[F[_]: Applicative, T]: Codec[F, T, T] =
     Codec(_.pure[F], _.pure[F])
@@ -65,21 +72,10 @@ object Codec {
   implicit def swap[F[_], A, B](implicit cod: Codec[F, A, B]): Codec[F, B, A] =
     Codec[F, B, A](cod.decode, cod.encode)
 
-  implicit def byteVectorArray[F[_]: Applicative]: Codec[F, Array[Byte], ByteVector] =
-    pure(ByteVector.apply, _.toArray)
-
-  // TODO: descriptive error
-  implicit def byteVectorB64[F[_]](implicit F: ApplicativeError[F, Throwable]): Codec[F, String, ByteVector] =
-    Codec(
-      str ⇒
-        ByteVector
-          .fromBase64(str)
-          .fold[F[ByteVector]](
-            F.raiseError(new IllegalArgumentException(s"Given string is not valid b64: $str"))
-          )(_.pure[F]),
-      _.toBase64.pure[F]
-    )
-
+  @deprecated(
+    "Codec is planned for removing soon, as it's impure and not properly tested. Use PureCodec instead.",
+    "6.4.2018"
+  )
   def codec[F[_], O, B](implicit codec: Codec[F, O, B]): Codec[F, O, B] = codec
 
   /**
@@ -92,6 +88,10 @@ object Codec {
    * @tparam B Encoded type
    * @return New codec for O and B
    */
+  @deprecated(
+    "Codec is planned for removing soon, as it's impure and not properly tested. Use PureCodec instead.",
+    "6.4.2018"
+  )
   def pure[F[_]: Applicative, O, B](encodeFn: O ⇒ B, decodeFn: B ⇒ O): Codec[F, O, B] =
     Codec(encodeFn(_).pure[F], decodeFn(_).pure[F])
 }
diff --git a/core/src/main/scala/fluence/codec/CodecError.scala b/core/src/main/scala/fluence/codec/CodecError.scala
index e7a72ce..d26c4c0 100644
--- a/core/src/main/scala/fluence/codec/CodecError.scala
+++ b/core/src/main/scala/fluence/codec/CodecError.scala
@@ -26,6 +26,7 @@ import scala.util.control.NoStackTrace
  * it's returned in the left side of Either(T) by PureCodec transformations.
  *
  * @param message Error message
+ * @param causedBy Error cause for wrapped exceptions
  */
 case class CodecError(message: String, causedBy: Option[Throwable] = None) extends NoStackTrace {
   override def getMessage: String = message
diff --git a/core/src/main/scala/fluence/codec/MonadicalEitherArrow.scala b/core/src/main/scala/fluence/codec/MonadicalEitherArrow.scala
index e786b6f..d3049bc 100644
--- a/core/src/main/scala/fluence/codec/MonadicalEitherArrow.scala
+++ b/core/src/main/scala/fluence/codec/MonadicalEitherArrow.scala
@@ -27,7 +27,7 @@ import scala.language.higherKinds
 import scala.util.Try
 
 /**
- * MonadicalEitherFunc wraps Func and Bijection with a fixed E error type.
+ * MonadicalEitherArrow wraps Func and Bijection with a fixed E error type.
  *
  * @tparam E Error type
  */
@@ -108,6 +108,10 @@ abstract class MonadicalEitherArrow[E <: Throwable] {
      */
     lazy val swap: Bijection[B, A] = Bijection(inverse, direct)
 
+    @deprecated(
+      "You should keep codec Pure until running direct or inverse on it: there's no reason to bind effect into Codec",
+      "6.4.2018"
+    )
     def toCodec[F[_]](implicit F: MonadError[F, Throwable]): Codec[F, A, B] =
       Codec(direct.runF[F], inverse.runF[F])
   }
@@ -144,6 +148,11 @@ abstract class MonadicalEitherArrow[E <: Throwable] {
         Traverse[G].traverse[EitherT[F, E, ?], A, B](input)(f.apply[F](_))
     }
 
+  /**
+   * Bijection Summoner -- useful for making a composition of bijections.
+   */
+  def apply[A, B](implicit bijection: Bijection[A, B]): Bijection[A, B] = bijection
+
   /**
    * Lifts a pure function into Func context.
    *
diff --git a/core/src/main/scala/fluence/codec/PureCodec.scala b/core/src/main/scala/fluence/codec/PureCodec.scala
index 3fd8506..7af6939 100644
--- a/core/src/main/scala/fluence/codec/PureCodec.scala
+++ b/core/src/main/scala/fluence/codec/PureCodec.scala
@@ -17,26 +17,11 @@
 
 package fluence.codec
 
-import scodec.bits.{Bases, ByteVector}
-
 /**
  * PureCodec default values.
  */
 object PureCodec extends MonadicalEitherArrow[CodecError] {
 
-  implicit val byteArrayToVector: PureCodec[Array[Byte], ByteVector] =
-    liftB(ByteVector.apply, _.toArray)
-
-  implicit val base64ToVector: PureCodec[String, ByteVector] =
-    liftEitherB(
-      str ⇒
-        ByteVector
-          .fromBase64Descriptive(str, Bases.Alphabets.Base64)
-          .left
-          .map(CodecError(_)),
-      vec ⇒ Right(vec.toBase64(Bases.Alphabets.Base64))
-    )
-
   /**
    * Summons an implicit codec.
    */
@@ -45,12 +30,12 @@ object PureCodec extends MonadicalEitherArrow[CodecError] {
   /**
    * Shortcut to build a PureCodec.Bijection with two Func's
    */
-  def apply[A, B](direct: Func[A, B], inverse: Func[B, A]): Bijection[A, B] =
+  def build[A, B](direct: Func[A, B], inverse: Func[B, A]): Bijection[A, B] =
     Bijection(direct, inverse)
 
   /**
    * Shortcut to build a PureCodec.Bijection with two pure functions
    */
-  def apply[A, B](direct: A ⇒ B, inverse: B ⇒ A): Bijection[A, B] =
+  def build[A, B](direct: A ⇒ B, inverse: B ⇒ A): Bijection[A, B] =
     liftB(direct, inverse)
 }
diff --git a/core/src/test/scala/fluence/codec/PureCodecSpec.scala b/core/src/test/scala/fluence/codec/PureCodecSpec.scala
index 47c45a8..f776bef 100644
--- a/core/src/test/scala/fluence/codec/PureCodecSpec.scala
+++ b/core/src/test/scala/fluence/codec/PureCodecSpec.scala
@@ -17,12 +17,9 @@
 
 package fluence.codec
 
-import cats.Id
 import cats.instances.try_._
-import cats.syntax.compose._
 import org.scalatest.prop.Checkers
 import org.scalatest.{Matchers, WordSpec}
-import scodec.bits.ByteVector
 
 import scala.util.Try
 
@@ -37,23 +34,5 @@ class PureCodecSpec extends WordSpec with Matchers with Checkers {
       }
 
     }
-
-    "convert base64 strings to byte vectors and vice versa" in {
-
-      val arrCodec = implicitly[PureCodec[Array[Byte], ByteVector]]
-      val b64Codec = implicitly[PureCodec[ByteVector, String]]
-
-      check { (bytes: List[Byte]) ⇒
-        (arrCodec andThen arrCodec.swap).direct.apply[Id](bytes.toArray).value.map(_.toList).contains(bytes) &&
-        (arrCodec andThen b64Codec andThen b64Codec.swap andThen arrCodec.swap).direct
-          .apply[Id](bytes.toArray)
-          .value
-          .map(_.toList)
-          .contains(bytes)
-      }
-
-      b64Codec.inverse[Id]("wrong input!").value.isLeft shouldBe true
-
-    }
   }
 }
diff --git a/protobuf/src/main/scala/fluence/codec/pb/ProtobufCodecs.scala b/protobuf/src/main/scala/fluence/codec/pb/ProtobufCodecs.scala
index e3ccd2e..865c9e3 100644
--- a/protobuf/src/main/scala/fluence/codec/pb/ProtobufCodecs.scala
+++ b/protobuf/src/main/scala/fluence/codec/pb/ProtobufCodecs.scala
@@ -19,18 +19,11 @@ package fluence.codec.pb
 
 import com.google.protobuf.ByteString
 import fluence.codec.PureCodec
-import scodec.bits.ByteVector
 
 import scala.language.higherKinds
 
 object ProtobufCodecs {
 
-  implicit val byteVectorByteString: PureCodec[ByteString, ByteVector] =
-    PureCodec.liftB(
-      str ⇒ ByteVector(str.toByteArray),
-      vec ⇒ ByteString.copyFrom(vec.toArray)
-    )
-
   implicit val byteArrayByteString: PureCodec[ByteString, Array[Byte]] =
     PureCodec.liftB(
       str ⇒ str.toByteArray,