diff --git a/.cirrus.yaml b/.cirrus.yaml
new file mode 100644
index 0000000..a430812
--- /dev/null
+++ b/.cirrus.yaml
@@ -0,0 +1,11 @@
+freebsd_instance:
+  image_family: freebsd-13-1
+
+task:
+  install_script: pkg install -y ghc hs-cabal-install git
+  script:
+    - ghc --version
+    - cabal --version
+    - cabal update
+    - cabal test --test-show-details=direct --enable-tests
+    - cabal test -f-simd --test-show-details=direct --enable-tests
diff --git a/.cirrus.yml b/.cirrus.yml
deleted file mode 100644
index b984c60..0000000
--- a/.cirrus.yml
+++ /dev/null
@@ -1,11 +0,0 @@
-freebsd_instance:
-  image_family: freebsd-13-1
-
-task:
-  install_script: pkg install -y ghc hs-cabal-install git
-  script:
-    - ghc --version
-    - cabal --version
-    - cabal update
-    - cabal test --test-show-details=direct -c 'quickcheck-classes -semigroupoids -aeson -semirings' --enable-tests
-    - cabal test -f-simd --test-show-details=direct -c 'quickcheck-classes -semigroupoids -aeson -semirings' --enable-tests
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yaml
similarity index 54%
rename from .github/workflows/ci.yml
rename to .github/workflows/ci.yaml
index 0ba092e..dd32e22 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yaml
@@ -19,7 +19,7 @@ jobs:
         ghc: ['9.6', '9.4', '9.2', '9.0', '8.10', '8.8.4', '8.8.2', '8.8.1', '8.6', '8.4']
     steps:
     - uses: actions/checkout@v3
-    - uses: haskell/actions/setup@v2
+    - uses: haskell-actions/setup@v2
       id: setup-haskell-cabal
       with:
         ghc-version: ${{ matrix.ghc }}
@@ -31,20 +31,15 @@ jobs:
           ${{ steps.setup-haskell-cabal.outputs.cabal-store }}
           dist-newstyle
         key: ${{ runner.os }}-${{ matrix.ghc }}
-        restore-keys: |
-          ${{ runner.os }}-${{ matrix.ghc }}-
     - name: Build
       run: |
-        echo packages:. > cabal.project
-        echo tests:True >> cabal.project
-        echo "constraints:quickcheck-classes -semigroupoids -aeson -semirings" >> cabal.project
-        cabal test --test-show-details=direct
+        cabal test --enable-tests --test-show-details=direct
         cabal bench --benchmark-option=-l
         cabal sdist
         cabal check
     - name: Build without SIMD
       run: |
-        cabal test -f-simd --test-show-details=direct
+        cabal test -f-simd --enable-tests --test-show-details=direct
     - name: Haddock
       if: ${{ matrix.ghc != '8.0' && matrix.ghc != '8.2' && matrix.ghc != '8.4' }}
       run: cabal haddock
@@ -96,12 +91,78 @@ jobs:
           ghc --make -Isrc:test -isrc:test -DUseSIMD -o Tests cbits/bitvec_simd.c test/Main.hs +RTS -s
           ./Tests +RTS -s
 
+  js:
+    needs: build
+    runs-on: ubuntu-latest
+    env:
+      version: javascript-unknown-ghcjs-9.6.2
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions/cache@v3
+      name: Cache cabal stuff
+      with:
+        path: |
+          ~/.cabal/store
+          dist-newstyle
+        key: ${{ env.version }}
+    - name: Setup
+      run: |
+        ghcup config add-release-channel https://raw.githubusercontent.com/haskell/ghcup-metadata/develop/ghcup-cross-0.0.8.yaml
+        cabal update
+    - name: Install JS toolchain
+      run: |
+        git clone https://github.com/emscripten-core/emsdk.git
+        cd emsdk
+        ./emsdk install latest
+        ./emsdk activate latest
+        source ./emsdk_env.sh
+        cd ..
+        emconfigure ghcup install ghc --set ${{ env.version }}
+    - name: Build
+      run: |
+        cabal --with-compiler=javascript-unknown-ghcjs-ghc --with-hc-pkg=javascript-unknown-ghcjs-ghc-pkg build
+
+  wasm:
+    needs: build
+    runs-on: ubuntu-latest
+    env:
+      version: wasm32-wasi-9.8.0.20230927
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions/cache@v3
+      name: Cache cabal stuff
+      with:
+        path: |
+          ~/.cabal/store
+          dist-newstyle
+        key: ${{ env.version }}
+    - name: Setup
+      run: |
+        ghcup config add-release-channel https://raw.githubusercontent.com/haskell/ghcup-metadata/develop/ghcup-cross-0.0.8.yaml
+        cabal update
+    - name: Install WASM toolchain
+      run: |
+        git clone https://gitlab.haskell.org/ghc/ghc-wasm-meta.git
+        cd ghc-wasm-meta/
+        export SKIP_GHC=yes
+        ./setup.sh
+        source ~/.ghc-wasm/env
+        ~/.ghc-wasm/add_to_github_path.sh
+        cd ..
+        ghcup install ghc --set ${{ env.version }} -- --host=x86_64-linux --with-intree-gmp --with-system-libffi
+    - name: Build
+      run: |
+        mv cabal.project.wasi cabal.project.local
+        cabal --with-compiler=wasm32-wasi-ghc --with-hc-pkg=wasm32-wasi-ghc-pkg build --enable-tests
+        cabal --with-compiler=wasm32-wasi-ghc --with-hc-pkg=wasm32-wasi-ghc-pkg list-bin test:bitvec-tests --enable-tests
+        wasmtime $(cabal --with-compiler=wasm32-wasi-ghc --with-hc-pkg=wasm32-wasi-ghc-pkg list-bin test:bitvec-tests --enable-tests)
+
   bounds-checking:
     needs: build
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - uses: haskell/actions/setup@v2
+    - uses: haskell-actions/setup@v2
       id: setup-haskell-cabal
       with:
         ghc-version: 'latest'
@@ -116,11 +177,8 @@ jobs:
         key: ${{ runner.os }}-latest
     - name: Test
       run: |
-        echo packages:. > cabal.project
-        echo tests:True >> cabal.project
-        echo "constraints:quickcheck-classes -semigroupoids -aeson -semirings" >> cabal.project
         echo "constraints:vector +unsafechecks +internalchecks" >> cabal.project
         # Some tests are filtered out because of
         # https://gitlab.haskell.org/ghc/ghc/-/issues/23132
-        cabal run tests --test-show-details=direct --ghc-options='-fcheck-prim-bounds -fno-ignore-asserts' -- -p '$NF!~/cloneFromWords8/&&$NF!~/cloneToByteString/'
-        cabal run tests -f-simd --test-show-details=direct --ghc-options='-fcheck-prim-bounds -fno-ignore-asserts' -- -p '$NF!~/cloneFromWords8/&&$NF!~/cloneToByteString/'
+        cabal run tests --enable-tests --test-show-details=direct --ghc-options='-fcheck-prim-bounds -fno-ignore-asserts' -- -p '$NF!~/cloneFromWords8/&&$NF!~/cloneToByteString/'
+        cabal run tests -f-simd --enable-tests --test-show-details=direct --ghc-options='-fcheck-prim-bounds -fno-ignore-asserts' -- -p '$NF!~/cloneFromWords8/&&$NF!~/cloneToByteString/'
diff --git a/.gitignore b/.gitignore
index 80e2db4..334f427 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,3 +27,9 @@ dist-newstyle
 
 cabal.sandbox.config
 .cabal-sandbox
+
+########
+# IDEs #
+########
+
+.vscode
diff --git a/bitvec.cabal b/bitvec.cabal
index 858596d..43e9191 100644
--- a/bitvec.cabal
+++ b/bitvec.cabal
@@ -128,7 +128,9 @@ test-suite bitvec-tests
     Tests.SetOps
     Tests.SetOpsTS
     Tests.Vector
-  ghc-options: -Wall -threaded -rtsopts -Wcompat
+  ghc-options: -Wall -Wcompat
+  if !arch(wasm32)
+    ghc-options: -threaded -rtsopts
   include-dirs: test
 
   if impl(ghc <9.0)
diff --git a/cabal.project b/cabal.project
new file mode 100644
index 0000000..868d232
--- /dev/null
+++ b/cabal.project
@@ -0,0 +1,4 @@
+packages: .
+
+package quickcheck-classes
+    flags: -aeson -semigroupoids -semirings
diff --git a/cabal.project.wasi b/cabal.project.wasi
new file mode 100644
index 0000000..386cf71
--- /dev/null
+++ b/cabal.project.wasi
@@ -0,0 +1,5 @@
+-- https://github.com/haskellari/splitmix/pull/73
+source-repository-package
+  type: git
+  location: https://github.com/amesgen/splitmix.git
+  tag: 83b906c4bcdc2720546f1779a16eb65e8e12ecba