diff --git a/js/src/devtools/automation/variants/wasi b/js/src/devtools/automation/variants/wasi
new file mode 100644
index 000000000000..a02dfc0c6bec
--- /dev/null
+++ b/js/src/devtools/automation/variants/wasi
@@ -0,0 +1,14 @@
+{
+    "configure-args": "--enable-application=js --target=wasm32-unknown-wasi --with-sysroot=${MOZ_FETCHES_DIR}/wasi-sysroot/share/wasi-sysroot/ --disable-stdcxx-compat --disable-gold --without-system-zlib --without-intl-api --disable-jit --disable-shared-js --disable-shared-memory --disable-tests --disable-cranelift --disable-clang-plugin",
+    "optimize": true,
+    "debug": false,
+    "nspr": false,
+    "compiler": "clang",
+    "env": {
+        "JITTEST_EXTRA_ARGS": "--jitflags=none"
+    },
+    "skip-tests": {
+        "all": ["jstests", "jittest", "jsapitests"]
+    },
+    "use_minidump": false
+}
diff --git a/taskcluster/ci/spidermonkey/linux.yml b/taskcluster/ci/spidermonkey/linux.yml
index 7467932960ba..5d8d255c928a 100644
--- a/taskcluster/ci/spidermonkey/linux.yml
+++ b/taskcluster/ci/spidermonkey/linux.yml
@@ -305,6 +305,25 @@ sm-compacting-linux64/debug:
             - linux64-llvm-symbolizer
             - linux64-sysroot
 
+sm-linux64-wasi/opt:
+    description: "Spidermonkey WASI opt build"
+    index:
+        job-name: sm-linux64-wasi-opt
+    treeherder:
+        platform: linux64/opt
+        symbol: SM(wasi)
+        tier: 3
+    run:
+        spidermonkey-variant: wasi
+    run-on-projects: ['mozilla-central']
+    fetches:
+        toolchain:
+            - linux64-clang
+            - linux64-rust
+            - linux64-cbindgen
+            - linux64-dump-syms
+            - wasi-sysroot-12
+
 sm-msan-linux64/opt:
     description: "Spidermonkey Memory Sanitizer"
     index:
diff --git a/taskcluster/ci/toolchain/rust.yml b/taskcluster/ci/toolchain/rust.yml
index 1d7a565c271e..679f294ddb6a 100644
--- a/taskcluster/ci/toolchain/rust.yml
+++ b/taskcluster/ci/toolchain/rust.yml
@@ -21,6 +21,7 @@ linux64-rust-1.47:
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'i686-unknown-linux-gnu',
             '--target', 'aarch64-unknown-linux-gnu',
+            '--target', 'wasm32-wasi',
             '--compiler-builtins-hack',
         ]
     fetches:
@@ -53,6 +54,7 @@ linux64-rust-1.53:
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'i686-unknown-linux-gnu',
             '--target', 'aarch64-unknown-linux-gnu',
+            '--target', 'wasm32-wasi',
             '--compiler-builtins-hack',
         ]
         toolchain-alias: linux64-rust