diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c41463e..fb71caa 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [2.12, 2.13, 3]
+        scala: [2.13, 3]
         java: [temurin@8]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
@@ -67,11 +67,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v'))
-        run: mkdir -p target project/target
+        run: mkdir -p target jvm/target js/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v'))
-        run: tar cf targets.tar target project/target
+        run: tar cf targets.tar target jvm/target js/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v'))
@@ -108,16 +108,6 @@ jobs:
         if: matrix.java == 'temurin@8' && steps.setup-java-temurin-8.outputs.cache-hit == 'false'
         run: sbt +update
 
-      - name: Download target directories (2.12)
-        uses: actions/download-artifact@v4
-        with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12
-
-      - name: Inflate target directories (2.12)
-        run: |
-          tar xf targets.tar
-          rm targets.tar
-
       - name: Download target directories (2.13)
         uses: actions/download-artifact@v4
         with:
diff --git a/.mergify.yml b/.mergify.yml
index c10a885..53e0fbd 100644
--- a/.mergify.yml
+++ b/.mergify.yml
@@ -12,7 +12,6 @@ pull_request_rules:
   - or:
     - body~=labels:.*early-semver-patch
     - body~=labels:.*early-semver-minor
-  - status-success=Build and Test (ubuntu-latest, 2.12, temurin@8)
   - status-success=Build and Test (ubuntu-latest, 2.13, temurin@8)
   - status-success=Build and Test (ubuntu-latest, 3, temurin@8)
   actions:
diff --git a/build.sbt b/build.sbt
index c25535e..fb43586 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,8 +1,8 @@
 ThisBuild / organization := "com.dwolla"
 ThisBuild / homepage := Option(url("https://github.com/Dwolla/natchez-smithy4s"))
 ThisBuild / tlBaseVersion := "0.1"
-ThisBuild / crossScalaVersions := Seq("2.12.19", "2.13.14", "3.3.3")
-ThisBuild / githubWorkflowScalaVersions := Seq("2.12", "2.13", "3")
+ThisBuild / crossScalaVersions := Seq("2.13.14", "3.3.3")
+ThisBuild / githubWorkflowScalaVersions := Seq("2.13", "3")
 ThisBuild / tlJdkRelease := Option(8)
 ThisBuild / tlFatalWarnings := githubIsWorkflowBuild.value
 ThisBuild / startYear := Option(2024)
@@ -22,17 +22,23 @@ ThisBuild / mergifyStewardConfig ~= { _.map {
     .withMergeMinors(true)
 }}
 
-lazy val `natchez-smithy4s` = project
-  .in(file("."))
-  .enablePlugins(Smithy4sCodegenPlugin)
+lazy val `natchez-smithy4s` = crossProject(JVMPlatform, JSPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("core"))
   .settings(
+    Compile / smithy4sInputDirs := List(
+      baseDirectory.value.getParentFile / "src" / "main" / "smithy",
+    ),
     libraryDependencies ++= {
       Seq(
-        "com.disneystreaming.smithy4s" %% "smithy4s-core" % smithy4sVersion.value,
-        "com.disneystreaming.smithy4s" %% "smithy4s-http4s" % smithy4sVersion.value,
-        "com.disneystreaming.smithy4s" %% "smithy4s-cats" % smithy4sVersion.value,
-        "com.disneystreaming.smithy4s" %% "smithy4s-json" % smithy4sVersion.value,
-        "org.tpolecat" %% "natchez-core" % "0.3.5",
+        "com.disneystreaming.smithy4s" %%% "smithy4s-core" % smithy4sVersion.value,
+        "com.disneystreaming.smithy4s" %%% "smithy4s-json" % smithy4sVersion.value,
+        "org.tpolecat" %%% "natchez-core" % "0.3.5",
       )
     },
   )
+  .enablePlugins(Smithy4sCodegenPlugin)
+
+lazy val root = tlCrossRootProject
+  .aggregate(`natchez-smithy4s`)
+  .enablePlugins(NoPublishPlugin)
diff --git a/src/main/scala/com/dwolla/tracing/smithy/SchemaVisitorTraceableValue.scala b/core/src/main/scala/com/dwolla/tracing/smithy/SchemaVisitorTraceableValue.scala
similarity index 100%
rename from src/main/scala/com/dwolla/tracing/smithy/SchemaVisitorTraceableValue.scala
rename to core/src/main/scala/com/dwolla/tracing/smithy/SchemaVisitorTraceableValue.scala
diff --git a/src/main/smithy/natchez.smithy b/core/src/main/smithy/natchez.smithy
similarity index 100%
rename from src/main/smithy/natchez.smithy
rename to core/src/main/smithy/natchez.smithy
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 97128df..050e6c2 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,4 +1,6 @@
+addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.3.2")
 addSbtPlugin("org.typelevel" % "sbt-typelevel-ci-release" % "0.7.1")
 addSbtPlugin("org.typelevel" % "sbt-typelevel-mergify" % "0.7.1")
 addSbtPlugin("org.typelevel" % "sbt-typelevel-settings" % "0.7.1")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.16.0")
 addSbtPlugin("com.disneystreaming.smithy4s"  % "smithy4s-sbt-codegen" % "0.18.22")